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eHam Forums => Amplifiers => Topic started by: VK3BL on July 01, 2017, 09:40:38 PM



Title: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: VK3BL on July 01, 2017, 09:40:38 PM
Just wondering peoples opinions.

The HL-2.5Kfx runs a pair of ARF1500s but is limited to 10M

The HL-2500Kfx runs 6x THP2933s but will do 6M

What are people's thoughts?



Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KC4ZGP on July 02, 2017, 05:29:56 AM
You won't get opinions here. You'll get bias.

$6,500.00 for a single of piece amateur radio equipment. No longer is
amatuer radio that of the humble hobbyist.

We're now flashy, empty and shallow.

Kraus





Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: VK3BL on July 02, 2017, 07:38:04 AM
You won't get opinions here. You'll get bias.

$6,500.00 for a single of piece amateur radio equipment. No longer is
amatuer radio that of the humble hobbyist.

We're now flashy, empty and shallow.

Kraus

Kraus,

I think you'll find that by being humble and investing slowly over the years in second hand equipment (of the right condition) and then on selling your previously bought second hand gear (kept in good condition) one can build quite a nice shack.

This isn't a 1 year hobby.  This is a lifetime hobby, and good gear lasts a very very long time if treated with respect.

PS. You may need to install an attenuator in your EB-104 when driving it with your new Alinco.  The SR8T only offers 3 power levels, low 5w, medium 30w, high 100w.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KC4ZGP on July 02, 2017, 09:20:10 AM
J.D.,

My Bird show about 100 watts-high, 10 watts-low and the needle barely moves on
S-low, or 'supper low' as the manual says. Actually looks like near two watts.

And that's another project. I have a step attenuator and I attach it to the transceivers' outputs.
I still have my TS-450S;a ship I shall not abandon. But the problem is attenuation occurs
both directions.

If incoming signals are strong to moderately strong no problem. But...

I'm working on the faraday cage for the EB-104. 160 meter filter seems to work well. I see five hundred
watts out and reflected power nil or close to nil. And that's when the Bird is before or after the
filter.

Have fun and be safe my friend. We need you.

Kraus




Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: K6AER on July 02, 2017, 09:34:06 AM
I find it interesting that more and more hams cannot or will not own a price of equipment that requires more work than an On/Off switch.  Tuning a tube amplifier takes about 15 seconds. Once you  write the numbers down it takes 6 seconds.  Last night I checked the hams adds and there were over 100 legal limit tube amplifiers for under $2500.

The extra  money saved on an amplifier would provide a nice used tower and beam.

As for 6 meters do you currently work the band? On 6 meters you need at least a 4 element beam above 30 feet to make any contacts. Most hams work the band a little and never come back.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: K7JQ on July 02, 2017, 09:53:37 AM
How about a "based-opinion"?  ;)

Anything manufactured by Tokyo Hy-Power was pure quality. From what I understand, the collapse of Japan's commercial amplifier market led to their downfall, and the amateur radio division was not enough to sustain profitability. I owned a HL-1.5kfx for seven years with zero problems, even through heavy contest use. Sold it when they went belly-up, for fear that it wouldn't be repairable should something eventually cause it to fail.

The 2500 was an upgrade of the 2.5, and was released just before THP's demise. It used newer SS finals, provided more headroom, and added 6 meters. I've only seen or heard only a few of them actually out there. If you can find one and not afraid of possible unobtainium parts, it's a great, quality amp.

As far as price, $6,500 is about (or less than) on par with other current or soon to be released legal limit SS amps. If you have the financial capability for one of these new amps, and it's what you want, why not? Who says that not being a "humble hobbyist" makes one" "flashy, empty, and hollow"? I never make it a practice to count or comment on other people's money.



Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KT0DD on July 02, 2017, 09:57:10 AM
I understand that N4ATS who is an FL-7000 expert will work on THP stuff. The only thing that may be an issue is parts availability but I'll bet he can find workarounds.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: W8JX on July 02, 2017, 10:14:48 AM
Just wondering peoples opinions.

The HL-2.5Kfx runs a pair of ARF1500s but is limited to 10M

The HL-2500Kfx runs 6x THP2933s but will do 6M

What are people's thoughts?


Given that THP went belly up some time ago I would not invest a lot in it unless you are real good with making your own repairs. It is not that it was a poor quality unit but rather because there is no OEM support for it


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KC4ZGP on July 02, 2017, 11:27:11 AM


K6AER, JX,

I too wonder what's with the automatic-ness of ham radio. All the fun is turning knobs,
flipping switches, cussing.

My EB-104 is quite the manual-op. I have to check voltages, connect the filter, the matcher,
the 'Bird'. By the time it's all connected, I fall asleep. And please don't somebody say, "A factory
built amplifier will make it easier." No it won't! Boy oh boy! I have fun.

Kraus


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: N2SR on July 02, 2017, 12:08:38 PM
Buy them both.



Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: VK3BL on July 02, 2017, 02:36:45 PM
I find it interesting that more and more hams cannot or will not own a price of equipment that requires more work than an On/Off switch.  Tuning a tube amplifier takes about 15 seconds. Once you  write the numbers down it takes 6 seconds.  Last night I checked the hams adds and there were over 100 legal limit tube amplifiers for under $2500.

Its an academic question, as I own a HL-2.5Kfx, and am never likely to own the HL-2500FX.  I also did not spend more than your suggested budget to acquire one in mint condition with box, and will never have to worry about a bad tube again.

You assume too much in your first statement - I love tube amps.  In an ideal world I'd own an Alpha 87A or an OM Power 4000, heck even a Henry 8K.

The simple fact is in VK unless you want an AL-811 or FL-2100B, you take what you can find on the market.  My previous amps were the AL-811 and AL-572.

As for the THP, well its unbelievable; I can leave it on all day every day without worry of tubes going soft, and change bands remotely from work etc to chase DX.  It only uses 2 MOSFETs, which are both still available.



Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: K2GWK on July 02, 2017, 02:41:48 PM
Just wondering peoples opinions.

The HL-2.5Kfx runs a pair of ARF1500s but is limited to 10M

The HL-2500Kfx runs 6x THP2933s but will do 6M

What are people's thoughts?


Why is everyone so afraid of repairing a solid state amplifier? The circuits involved are not very complicated. Basic transistor theory is all that is needed.

Given that THP went belly up some time ago I would not invest a lot in it unless you are real good with making your own repairs. It is not that it was a poor quality unit but rather because there is no OEM support for it


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KC4ZGP on July 05, 2017, 06:28:24 AM

GWK,

We builders are shrinking in numbers.

I just finished my EB-104 foot pedal. I got tired of having to hold down the relay with a wooden stick
to transmit 500 of raw RF power. Actually it's not raw. It goes through my 'homebrewed' low-pass filter.

The foot pedal is made of a windows blinds slat. Hinged with tape and a nut/bolt to keep the halves
from slipping. The spring is a fat sponge leftover when we laid ceramic tiles. A micro switch
installed and a wooden stump to keep me from smashing the switch.

Hokey, tacky and hokey says the wife. That means I created a thing of beauty.

Soon, my copper sheeting arrives. I'll finish the EB-104's faraday cloche.

Kraus


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: W8JX on July 05, 2017, 06:48:07 AM

Why is everyone so afraid of repairing a solid state amplifier? The circuits involved are not very complicated. Basic transistor theory is all that is needed.


It is because the PA output devices themselves may become obsolete and hard to find or very expensive as these devices are still evolving and they drop older designs from production after several years. Aslo unlike a simple pull and replace tube, you have to make sure SS device is properly installed for good thermal transfer to heatsink.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: AC2RY on July 05, 2017, 07:02:43 AM


K6AER, JX,

I too wonder what's with the automatic-ness of ham radio. All the fun is turning knobs,
flipping switches, cussing.

My EB-104 is quite the manual-op. I have to check voltages, connect the filter, the matcher,
the 'Bird'. By the time it's all connected, I fall asleep. And please don't somebody say, "A factory
built amplifier will make it easier." No it won't! Boy oh boy! I have fun.

Kraus


There is still a lot of nobs to turn adjusting DSP filters for best reception or voice compressor for best transmission. Amplifier should be just an extension of your tranceiver, fully self controlled and managed. It does not matter if it uses tubes or transistors in final.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: AD5X on July 05, 2017, 08:41:11 AM
... As for 6 meters do you currently work the band? On 6 meters you need at least a 4 element beam above 30 feet to make any contacts. Most hams work the band a little and never come back.

I beg to differ. I've been playing on 6M since I was in high school (in the 60's) when I used a Lafayette HA-650 1W AM radio and a squalo on Dad's chimney in Maryland. I often worked into the mid-west, and even once into Cuba.  Now I have a K3, but just a dipole on my chimney.  I easily work both coasts from Texas when the band is open. A beam is great if you are a serious 6M operator, but not necessary for casual operators. 6M is one of my favorite bands.

Phil - AD5X


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: W8JX on July 05, 2017, 08:43:02 AM

There is still a lot of nobs to turn adjusting DSP filters for best reception or voice compressor for best transmission. Amplifier should be just an extension of your tranceiver, fully self controlled and managed. It does not matter if it uses tubes or transistors in final.


If you do not need to know how to use a amp without everything being automatic exactly what is "amateur radio" about it? More glorified PnP CB than ham radio. I guess it goes with new lack of real knowledge and skills requirement to get a ticket. Lets hope that they do not reduce requirements for other "trades"


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: K7JQ on July 05, 2017, 09:13:45 AM

There is still a lot of nobs to turn adjusting DSP filters for best reception or voice compressor for best transmission. Amplifier should be just an extension of your tranceiver, fully self controlled and managed. It does not matter if it uses tubes or transistors in final.


If you do not need to know how to use a amp without everything being automatic exactly what is "amateur radio" about it? More glorified PnP CB than ham radio. I guess it goes with new lack of real knowledge and skills requirement to get a ticket. Lets hope that they do not reduce requirements for other "trades"

No different than yesteryear's transceivers and transmitters that used tube PA's, requiring Pi-net tuning. It's called advances in technology. I had a SS amp, and now a manual tune tube amp...changing bands and tune-up requires all of about 10-15 seconds. No big deal. Plenty of "old school" technically capable hams are now using SS amps. Whatever meets your needs.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KC4ZGP on July 05, 2017, 10:59:54 AM

Hey JX,

Been using my Alinco SR8T with my D-104 and EB-104. Hmmm...I must like 104.

Anyway, I had to read the SR8T's instructions...a lot. Many buttons to find and push.

It ain't as simple a transceiver to operate as I thought. Maybe one should display
competence by setting up an SR8T to get a license.

Question Pool:

1. Set power to 10 watts and deactivate the speech compression.

2. Select a frequency.

3. Solder two wires together.

ETC.

Kraus


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: N0YXB on July 05, 2017, 11:15:10 AM

There is still a lot of nobs to turn adjusting DSP filters for best reception or voice compressor for best transmission. Amplifier should be just an extension of your tranceiver, fully self controlled and managed. It does not matter if it uses tubes or transistors in final.


If you do not need to know how to use a amp without everything being automatic exactly what is "amateur radio" about it? More glorified PnP CB than ham radio. I guess it goes with new lack of real knowledge and skills requirement to get a ticket. Lets hope that they do not reduce requirements for other "trades"

It's about a lot more than tuning up an amplifier. Not sure why you paint with such a broad brush. There are lots of appliance operators out there, and that's okay too. But many new hams seem to be doing a lot of things other than keying a mic for SSB contacts. How about satellites, EME, building antennas, and SOTA, to name just a few. Your negative colored glasses are showing again...


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: AC2RY on July 05, 2017, 02:30:25 PM

There is still a lot of nobs to turn adjusting DSP filters for best reception or voice compressor for best transmission. Amplifier should be just an extension of your tranceiver, fully self controlled and managed. It does not matter if it uses tubes or transistors in final.


If you do not need to know how to use a amp without everything being automatic exactly what is "amateur radio" about it? More glorified PnP CB than ham radio. I guess it goes with new lack of real knowledge and skills requirement to get a ticket. Lets hope that they do not reduce requirements for other "trades"

It takes a lot of knowledge and effort to make modem, transceiver, amplifier, antenna coupler and other components in the chain to work smoothly together when they are all from different brands. But when all things are set, amplifier function should be completely transparent for operator, creating an illusion of having 1.5kW output from right from transceiver. At work when I have to repeat any task more than 10 times in a row, I automate it. I change operating band/frequency more than that each time I on the air.  That is why for me all should "magically" happen on its own when I USE my radio. Even 15 seconds (actually more than that) it takes to manually tune tube amplifier it too much when you try to work DX.
 
 


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: K2GWK on July 05, 2017, 02:49:35 PM

Why is everyone so afraid of repairing a solid state amplifier? The circuits involved are not very complicated. Basic transistor theory is all that is needed.


It is because the PA output devices themselves may become obsolete and hard to find or very expensive as these devices are still evolving and they drop older designs from production after several years. Aslo unlike a simple pull and replace tube, you have to make sure SS device is properly installed for good thermal transfer to heatsink.

It still does not make sense to me. I have a HL-1.2Kfx and have a couple of sets of finals on hand. I have had the amp for a pretty long time and it is pretty bullet proof. I may never need them (fingers crossed)


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: AC2RY on July 05, 2017, 03:32:16 PM

Why is everyone so afraid of repairing a solid state amplifier? The circuits involved are not very complicated. Basic transistor theory is all that is needed.


It is because the PA output devices themselves may become obsolete and hard to find or very expensive as these devices are still evolving and they drop older designs from production after several years. Aslo unlike a simple pull and replace tube, you have to make sure SS device is properly installed for good thermal transfer to heatsink.

It still does not make sense to me. I have a HL-1.2Kfx and have a couple of sets of finals on hand. I have had the amp for a pretty long time and it is pretty bullet proof. I may never need them (fingers crossed)

With modern gear main problem is availability of software if/when processor chips need replacement. Transistors used as finals are commonly available even 10 years after day they were discontinued. And unlike tubes, their shelf life measures in decades.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: K6AER on July 05, 2017, 04:33:58 PM
My tetrode amplifiers typically run 30 + years on ceramic tuses. Not so on glass envelope tubes.  Although the commerical broadcast  Industry has gone solid state most hams don'the have that kind of budget.
 






Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: W8JX on July 06, 2017, 04:25:52 AM
Even 15 seconds (actually more than that) it takes to manually tune tube amplifier it too much when you try to work DX.

This is lame. Even if I jump bands I can use preset and get pretty close in a few second but never seen a DX that this was a deal kill. The demand for automated amps goes with the increased lack of knowledge of those that tickets are given to these days. That and a bit of laziness. There was a time when most upper class hams and especially extra class hams knew how to properly tune and use a amp due to technical back ground and knowledge required. Todays plug and play ham lack skills and knowledge so answer is to automate ? Something is being lost here...


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: K7JQ on July 06, 2017, 06:35:24 AM
Even 15 seconds (actually more than that) it takes to manually tune tube amplifier it too much when you try to work DX.

This is lame. Even if I jump bands I can use preset and get pretty close in a few second but never seen a DX that this was a deal kill. The demand for automated amps goes with the increased lack of knowledge of those that tickets are given to these days. That and a bit of laziness. There was a time when most upper class hams and especially extra class hams knew how to properly tune and use a amp due to technical back ground and knowledge required. Todays plug and play ham lack skills and knowledge so answer is to automate ? Something is being lost here...

Do you still use a flip phone to text, having to press "7" four times to type "S"? Still using a spark-gap transmitter? Just messin' with you :D. You don't need a technical background to manually tune a tube amp. You just follow instructions like anything else. I know plenty of very smart, technologically savvy hams that had tube amps, and now own SS ones. Doesn't mean you're lazy or lack skills. Technology is changing. It's just a matter of choice...whatever meets your needs, and what you can afford.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KC4ZGP on July 06, 2017, 07:02:05 AM

Hooray for automation.

JX,

Calm down man. This is just a hobby.

I don't walk to work. I drive my Ford.
I don't add or subtract on paper. I use a calculator.
Etcetera, etcetera, etcetera.

On 20 meters phone, 2200UTC. Join me won't you.

Kraus


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: W8JX on July 06, 2017, 07:38:36 AM

 This is just a hobby.


As I recall ham radio was based on experimental proper knowledge was required to use equipment that had different standards that for unskilled users like CB and business band. Today the standards for required knowledge and skill for ticket is a joke. The only thing that really separates today's ham radio is easy to past multiple guess test that question and answer pool that is widely available and pocket book. Soon even easy test will be gone too. Perhaps if many had had tickets for nearly 50 years like myself you would clearly see how the hobby has degraded to little more than a modern CB.  Lets hope that they do not make it as easy to become a police officer or a doctor with reduced standards.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KC4ZGP on July 06, 2017, 09:18:26 AM

...and it's still just a hobby...

I'm on 20 meters phone this evening. Won't you join me.

Kraus


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: W8JX on July 06, 2017, 10:09:05 AM

...and it's still just a hobby...


Well CB was a hobby too. Enter new CB


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KC4ZGP on July 06, 2017, 10:52:21 AM

Yup!

Ten-four.

Affirmative Charlie.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: VK3BL on July 07, 2017, 02:51:30 AM
Wow barely any worthwhile responses.  Shows how uninformed you all are.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KC4ZGP on July 07, 2017, 10:56:53 AM

You're right. There sure were a lot of weird responses even silly responses.

Good thing you don't mean me or JX.

Kraus



Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: VK3BL on July 07, 2017, 09:22:25 PM
I asked a technical / design question and expected answers to questions like these:

1) Are single push pull amp designs better than multiple push pull combined amp designs
2) What are ARF1500 MOSFETs like compared to VRF/SD2933 MOSFETS?
3) What is the reputation for reliability of each amplifier?

Instead I got a whole bunch of crap about tube amplifiers, which is just ridiculous as anyone who frequents this forum knows I've done my time in that department.

I feel 'lets stick to the past' is such a stupid attitude for a hobby that was once on the cutting edge of RF development.  CBers currently do more work with SS amplifiers than Amateurs do.  And as for harmonics / dirty design, any off the shelf TVI filter will bring a 11/10M amp into compliance, as the 2nd, 4th, etc harmonics are beyond 52MHz...

So stop bitching about whether tubes or transistors are better, or whether increasing station automation detracts from operator skill.  There are plenty of other places to have those discussions.  But this thread posits a very specific question, and the vast majority of responses have been off topic and therefore useless in the context of the original question.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: VR2AX on July 08, 2017, 02:57:27 AM
He's just winding you up just ignore it.

Sometimes the issue lies in the question. Classic answer to "Mr x you're not answering my question "... "Mr a you're not asking the right question ".

Fair result at Eden Park.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KC4ZGP on July 08, 2017, 07:35:49 AM
Herr VK3BL,

You came here on your own, you expected, and are now disappointed. I cannot help you.

I still suggest build the EB-104 amplifier from Communications Concepts. It'll give you
something to do and give you a good feeling when it's all said, done and working.

You'll have to affix the heat sink, T/R relay, add a low pass filter and figure out the
power supply issue. I use two RS-35 in series with two RS-20s in parallel.

I get about four-hundred watts coupled with my Alico SR8T, D-104 and
delta loop antenna.

I finished the copper cubical cover for mine. I had to tame that RF.

You can fashion a power combiner and combine two EB-104s for 1,200 watts.

Is it in you to match the challenge.

This is a hobby.

73 to you and your family. Be safe. We need you.

Kraus



Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: VK3BL on July 08, 2017, 07:50:41 AM
Herr VK3BL,

You came here on your own, you expected, and are now disappointed. I cannot help you.

I still suggest build the EB-104 amplifier from Communications Concepts. It'll give you
something to do and give you a good feeling when it's all said, done and working.

You'll have to affix the heat sink, T/R relay, add a low pass filter and figure out the
power supply issue. I use two RS-35 in series with two RS-20s in parallel.

I get about four-hundred watts coupled with my Alico SR8T, D-104 and
delta loop antenna.

I finished the copper cubical cover for mine. I had to tame that RF.

You can fashion a power combiner and combine two EB-104s for 1,200 watts.

Is it in you to match the challenge.

This is a hobby.

73 to you and your family. Be safe. We need you.

Kraus



Kraus,

The EB-104 sure is an interesting design, having read the white paper from Motorola.  Specifically, it is novel in that it doesn't use/need a combiner despite having 4 sets.

You'll certainly have fun if you go down the combiner route, and good on you.

My personal favourite challenge is QRO.  I've got a beautiful ex ups case sitting in the garage for just the right project.  I still can't decide whether to go something like a 3CX3000A7 or a bunch of the latest LDMOS super chips.

Previously in my mind the tube route was mandatory, given the extreme linearity advantage of the 3CX3000A7, but these days with pre-distortion it really doesn't matter.

The answer will come to me one day, but lets face it, high current 50v supplies are cheap as chips these days, where as decent EHT transformers are not.

Anyway, I was hoping to get more feedback regarding the design aspects of this particular amplifier.

A previous post suggested I asked the wrong question; I'm more of the opinion I asked the wrong audience.

73,

Jarrad


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: NO9E on July 08, 2017, 08:31:47 AM
Quote
I asked a technical / design question and expected answers to questions like these:

1) Are single push pull amp designs better than multiple push pull combined amp designs
2) What are ARF1500 MOSFETs like compared to VRF/SD2933 MOSFETS?
3) What is the reputation for reliability of each amplifier?

Multiple push-pull amps require a combiner and are more complex. Single push-pull is better for reliability. At the time of THP, the only single push pull transistor that could deliver 1.5KW was ARF1500 operating at 125V. THP described the design in QEX. Lots so trouble getting a good match especially on 10m and not too good efficiency. No 6m.

Multiple push pull designs used established 600W modules and operated on 50V. No problem matching. New LDMOS can deliver legal limit with a single module at 50V. No problem with 6m or with efficiency.

I have Expert 2k-fa with 3 600W modules. One smoked and was replaced under warranty. Now the same company has a half-weight Expert 1.5k-fa with a single LDMOS module.

If any module in HL-2500 fails, instead of repairing it, it may be simpler to use  replacement LDMOS module. Same 50V.

THP had a very good reputation but their designs are dated. Also they required an external ATU; having internal ATU and an antenna switch greatly simplifies operations.

Ignacy, NO9E


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KC4ZGP on July 08, 2017, 01:55:00 PM

Jarrad,

I'm glad you have calmed down. Let's now talk EB-104.

Notice the drains and sources are connected directly to each other of either pair.
Then the pairs are connected push-pull.

The beauty of the FET is they can be paralleled without concern for drain-source
impedance problems. Like resistors, if you neeed more current with the same
voltage, just connect more resistors in parallel.

Same for the FET. However, gates must be kept apart as they are per the schematic.

My latest task is to add two FETs for six in all, three on each side. I have number five
and six added on the copper sheet heat spreader, their sources connected and their gates
biased at 3 volts d.c. I'm building up the courage to finally connect the drains and gates to
their outputs and inputs respectively.

I think my copper cubical is doing as it should. Folks actually come back with my call the
first time. So I take it RF from the antenna is blocked from re-entering the amplifier.

Duh! Kraus.

I will let you know how it goes. In the meantime begin your EB-104. You have your whole
life to complete it. You said the hobby is a lifetime thing not a 1-year thing.

73 and be safe. We need you.

Kraus


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KOP on July 10, 2017, 11:53:12 PM

 This is just a hobby.


As I recall ham radio was based on experimental proper knowledge was required to use equipment that had different standards that for unskilled users like CB and business band. Today the standards for required knowledge and skill for ticket is a joke. The only thing that really separates today's ham radio is easy to past multiple guess test that question and answer pool that is widely available and pocket book. Soon even easy test will be gone too. Perhaps if many had had tickets for nearly 50 years like myself you would clearly see how the hobby has degraded to little more than a modern CB.  Lets hope that they do not make it as easy to become a police officer or a doctor with reduced standards.

https://www.eham.net/ehamforum/smf/index.php/topic,115523.msg1005849.html#msg1005849 (https://www.eham.net/ehamforum/smf/index.php/topic,115523.msg1005849.html#msg1005849)

The OP's question was ...

Just wondering peoples opinions.

The HL-2.5Kfx runs a pair of ARF1500s but is limited to 10M

The HL-2500Kfx runs 6x THP2933s but will do 6M

What are people's thoughts?



How in the world do you get to ...


snip~ Today the standards for required knowledge and skill for ticket is a joke. The only thing that really separates today's ham radio is easy to past multiple guess test that question and answer pool that is widely available and pocket book. Soon even easy test will be gone too. Perhaps if many had had tickets for nearly 50 years like myself you would clearly see how the hobby has degraded to little more than a modern CB.  ~snip

I swear John, I could start a topic about muffin mix and you would be on page three ranting about the state of Amateur Radio as you see it !

Give it a rest will you. If nothing else it is boring in the extreme.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: W8JX on July 11, 2017, 11:05:31 AM
Give it a rest will you. If nothing else it is boring in the extreme.

Never will. New extra class is a joke and a insult to those that actually earned it and I take offense to any suggestion otherwise. 


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KC4ZGP on July 11, 2017, 12:26:01 PM

Hey JX,

I'm at a loss.

I'm on 17 meters phone at 2200UTC.

Won't you join me.

Kraus


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KD8MJR on July 11, 2017, 01:15:42 PM
Just wondering peoples opinions.

The HL-2.5Kfx runs a pair of ARF1500s but is limited to 10M

The HL-2500Kfx runs 6x THP2933s but will do 6M

What are people's thoughts?



A very close match but the edge goes to the 2.5Kfx.
I have both Amps and I guess if I was an avid 6M fan my opinion might differ but for 160-10M the 2.5Kfx is Superior in just about every way, mainly because it's built better in every way.   It uses a solid copper heatsink that weighs a ton and a huge transformer and caps for the 50Vdc.  The 2500fx uses an aluminum heat sink and dual switching power supplies that are just able to handle 1500W.
The 2.5Kfx will hit 2200W without skipping a beat, the 2500FX should never be run beyond 1500W or you risk burning out a power supply.  The real kicker is that the 2.5Kfx is actually a much smaller amp on the desk than the 2500FX.

73s
Rob


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: K7JQ on July 11, 2017, 05:47:28 PM
Just wondering peoples opinions.

The HL-2.5Kfx runs a pair of ARF1500s but is limited to 10M

The HL-2500Kfx runs 6x THP2933s but will do 6M

What are people's thoughts?



A very close match but the edge goes to the 2.5Kfx.
I have both Amps and I guess if I was an avid 6M fan my opinion might differ but for 160-10M the 2.5Kfx is Superior in just about every way, mainly because it's built better in every way.   It uses a solid copper heatsink that weighs a ton and a huge transformer and caps for the 50Vdc.  The 2500fx uses an aluminum heat sink and dual switching power supplies that are just able to handle 1500W.
The 2.5Kfx will hit 2200W without skipping a beat, the 2500FX should never be run beyond 1500W or you risk burning out a power supply.  The real kicker is that the 2.5Kfx is actually a much smaller amp on the desk than the 2500FX.

73s
Rob


Finally....a qualified response from an experienced THP user that has both amps.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: G3RZP on July 11, 2017, 06:03:37 PM
In post #4, K6AER said
Quote
I find it interesting that more and more hams cannot or will not own a price of equipment that requires more work than an On/Off switch.  Tuning a tube amplifier takes about 15 seconds. Once you  write the numbers down it takes 6 seconds.

I find it interesting that a large number of Extra Class calls appear totally unable to do this or actually understand what happens when they tune.

When I took the UK exam in 1963, you had to have at least some understanding of radio technology. It doesn't appear to be the same now, even in the UK requirements, let alone the US Extra Class (which is I believe, a broader spectrum than the UK).


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KC4ZGP on July 12, 2017, 05:25:25 AM

Do you mean to tell me I have been building my own equipment, less the transceiver and power supplies,
understanding whys and why nots and didn't need to at all.

Boy have I wasted my time. I'm gonna go get my extra license.

On 17 meters phone at 2200UTC.

Won't you join me.

Kraus



Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: N0YXB on July 12, 2017, 07:11:27 AM
Just wondering peoples opinions.

The HL-2.5Kfx runs a pair of ARF1500s but is limited to 10M

The HL-2500Kfx runs 6x THP2933s but will do 6M

What are people's thoughts?



A very close match but the edge goes to the 2.5Kfx.
I have both Amps and I guess if I was an avid 6M fan my opinion might differ but for 160-10M the 2.5Kfx is Superior in just about every way, mainly because it's built better in every way.   It uses a solid copper heatsink that weighs a ton and a huge transformer and caps for the 50Vdc.  The 2500fx uses an aluminum heat sink and dual switching power supplies that are just able to handle 1500W.
The 2.5Kfx will hit 2200W without skipping a beat, the 2500FX should never be run beyond 1500W or you risk burning out a power supply.  The real kicker is that the 2.5Kfx is actually a much smaller amp on the desk than the 2500FX.

73s
Rob


Finally....a qualified response from an experienced THP user that has both amps.

Indeed.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: K1LEM on July 13, 2017, 02:35:15 PM
 You folks realize 7000 dollars is on par and even more expensive than a several KW amplifier for FM broadcast? Whew.. as much as I am attracted to solid state of the art.. 7K No way, even if I had it.
But, each to their own, what does the XYL think of your little gift? ;D


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KC4ZGP on July 13, 2017, 05:08:52 PM

K1LEM,

Ten-Four to that. $7,000.00 for an amplifier?! Wow!

All this week I've been talking on my Alinco SR-8T, EB-104, delta loop and D-104 microphone. No one knows until I tell them.

Copper faraday shield works great.

One guy said voice OK but lacks some bass. Alrighty. I'm on it. Now experimenting with a capacitor in the D-104 to lower my voice.

And I shall re do power supplies. Three RS-35 and on RM 50 in series. Voltages set to 12.5 volts each for fifty volts. Just what
the EB-104 wants and needs.

Ranted enough.

Build it first folks.

Kraus


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: VR2AX on July 13, 2017, 05:59:19 PM

All this week I've been talking on my Alinco SR-8T, EB-104, delta loop and D-104 microphone. No one knows until I tell them.


I have an Alinco SR-8E among other radios. I did a fairly detailed technical review of it which is on eham. IMO it is a good radio, well built, and good value for money. Unlike my IC-7300 and some others I don't find myself scratching my head all the time to work out what to touch or turn.

The fixed power settings might be an issue with some tetrode or solid state amps, but it would make a good match with one of the several KW broadcast amps.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: KC4ZGP on July 14, 2017, 05:42:36 AM

Herr VR2AX,

RR.

If someone has issue with the SR8T, I suggest they un-issue the issue.

Amateur radio is about experimenting...try this...check that...take it apart and try something else.

Communicating? Contests? What are those Dr. FrankenKraus?

I didn't make it on the air yesterday evening but at 2200UTC Kraus will be on the air, 17 meters. Won't you join me.

Kraus


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: VK3BL on July 14, 2017, 08:29:00 PM
Just wondering peoples opinions.

The HL-2.5Kfx runs a pair of ARF1500s but is limited to 10M

The HL-2500Kfx runs 6x THP2933s but will do 6M

What are people's thoughts?


A very close match but the edge goes to the 2.5Kfx.
I have both Amps and I guess if I was an avid 6M fan my opinion might differ but for 160-10M the 2.5Kfx is Superior in just about every way, mainly because it's built better in every way.   It uses a solid copper heatsink that weighs a ton and a huge transformer and caps for the 50Vdc.  The 2500fx uses an aluminum heat sink and dual switching power supplies that are just able to handle 1500W.
The 2.5Kfx will hit 2200W without skipping a beat, the 2500FX should never be run beyond 1500W or you risk burning out a power supply.  The real kicker is that the 2.5Kfx is actually a much smaller amp on the desk than the 2500FX.

73s
Rob


Thanks Rob,

I love my HL-2.5Kfx, it is amazingly compact and has so much reserve capacity for its rated specs its unbelievable.  At our legal limit it can run into an 8:1 SWR without even noticing (reflected power below 250W).

Picked it up for a song and whist I do miss turning knobs etc I've been there done that are there are so many other aspects of the hobby to explore.

I keep my FT-101E around for those times I feel the need to load up a PA manually :)

Overall, its nice to have an amp that isn't rated using 'Ameritron Specs'. 

Not knocking Ameritron; I enjoyed both of mine but the analogy goes like this.

I once had a 1980s Toyota pickup 4cyl petrol that had a max speed of 120km/h but our max legal limit was 110km/h in the bush.  Sounds fine, right?  Well no, all it took was a little bit of wind and I couldn't even do the speed limit.

Now I drive a 2010 Nissan pickup with a 4cyl turbo diesel that can do beyond 140km/h and has no problem staying at 110km/h with cruise control...

I get a 25% discount when I go to the DMV for having no demerit points / good behaviour...


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: W1JTO on July 16, 2017, 09:56:33 PM
So I don't own either, but came close to ordering a new 2500 in November, just before THP went under.

I did buy 1500 Tuner (because it was all HRO had available) and a 1.5 Kfx AMP (which like the 1500 supporting 6m), I absolutely love this combo.

IMHO the magic of THP AMP is the matching tuners, they work perfectly, and combined with ICOM CIV are plug and play, they are really zero work once dialed in

I would get a 2.5 - to match the 1.5 tuner.  The 1500 tuners are just unavailable ... mine was one of 6 imported before the crash.

That leaves you with a 2.5 and a 1.5 tuner ...a great combo, finals are still available, and the power supply is rock solid

The 2500 uses a 6x 2933 which should loaf at full legal limit ...  But this is an new amp that didn't have time to mature

I have heard that the 2.5 finals use a toxic substance in manufacture so  something to carefully check out, if repairing.


Title: RE: Which is the better amp? The THP HL-2.5Kfx or the HL-2500Kfx
Post by: K2GWK on July 19, 2017, 02:25:17 AM
So I don't own either, but came close to ordering a new 2500 in November, just before THP went under.

I did buy 1500 Tuner (because it was all HRO had available) and a 1.5 Kfx AMP (which like the 1500 supporting 6m), I absolutely love this combo.

IMHO the magic of THP AMP is the matching tuners, they work perfectly, and combined with ICOM CIV are plug and play, they are really zero work once dialed in

I would get a 2.5 - to match the 1.5 tuner.  The 1500 tuners are just unavailable ... mine was one of 6 imported before the crash.

That leaves you with a 2.5 and a 1.5 tuner ...a great combo, finals are still available, and the power supply is rock solid

The 2500 uses a 6x 2933 which should loaf at full legal limit ...  But this is an new amp that didn't have time to mature

I have heard that the 2.5 finals use a toxic substance in manufacture so  something to carefully check out, if repairing.

The only trouble with the THP tuners is that the max SWR they will tune is 4:1.