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Author Topic: Best solid state linear for a newbie  (Read 16662 times)
N4ATS
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Posts: 799




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« Reply #30 on: November 16, 2013, 05:06:22 AM »

Just curious, what happened to:

"Best solid state linear for a newbie"

He is probably so far wrapped around the axles he will need Valium
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W4VR
Member

Posts: 1190


WWW

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« Reply #31 on: November 16, 2013, 08:26:34 AM »

You can buy a used PW-1 for a couple of grand, but beware of the serial number.  Anything above 1500 is probably a good bet, but stay away from lower serial numbers...they've had power supply problems with those.  I have two PW-1's, one is s/n 1200 and the other 1500.  I had to buy a new power supply for the 1200 one.  The 1500 one has worked flawlessly for many years.  I remote these amps...basement with remote head in room above.  Like any solid state amp they tend to have higher IMD than tube amps but not sufficiently more to be a problem.  If you want a complete automatic operation, including antenna switching, the PW-1 is the way to go.
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K7KBN
Member

Posts: 2763




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« Reply #32 on: November 17, 2013, 03:14:56 PM »

Depends on the bandwidth of the antenna.  Generally the lower the frequency (80 and 160 meters), just 10 KHz might require retuning.  On 20 and above, 50-100 KHz wouldn't be unusual.  You can sweep your antennas with something like the MFJ-259B and see what the 2:1 bandwidth, or 3:1 bandwidth is.

Let me see if I understand this correctly...

Since a dummy load has a relatively wide bandwidth, does that mean if I'm firing a tube amp into a dummy load, I can QSY from 160m to 10m without tuning the amp?

Likewise, does it also mean that if I have an automatic antenna tuner between the amp and the antenna, I don't have to tune the amp between bands?

I'm confused...

Question 1:  Normally yes.  Manufacturers' specifications for dummy loads tell what you need to know about the bandwidth of your particular DL.

Question 2: I suspect that would depend on the capabilities of the matching network
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73
Pat K7KBN
CWO4 USNR Ret.
N8YQX
Member

Posts: 66




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« Reply #33 on: November 17, 2013, 04:17:12 PM »

Depends on the bandwidth of the antenna.  Generally the lower the frequency (80 and 160 meters), just 10 KHz might require retuning.  On 20 and above, 50-100 KHz wouldn't be unusual.  You can sweep your antennas with something like the MFJ-259B and see what the 2:1 bandwidth, or 3:1 bandwidth is.

Let me see if I understand this correctly...

Since a dummy load has a relatively wide bandwidth, does that mean if I'm firing a tube amp into a dummy load, I can QSY from 160m to 10m without tuning the amp?

Likewise, does it also mean that if I have an automatic antenna tuner between the amp and the antenna, I don't have to tune the amp between bands?

I'm confused...

Question 1:  Normally yes.  Manufacturers' specifications for dummy loads tell what you need to know about the bandwidth of your particular DL.

Question 2: I suspect that would depend on the capabilities of the matching network

Not having operated a tube amp before, my knowledge is limited.  My understanding is that the plate needs to be adjusted for the operating frequency.  However, based on above response, that does not seem to be the case, as long as the antenna system is at resonance.

So, assuming my antenna tuner can tame the antenna system to a reasonable SWR (let's say below 1.5:1), I don't have to worry about tuning the amp, even if I QSY to a different band???
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73,
N8YQX
AD6KA
Member

Posts: 2232




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« Reply #34 on: November 17, 2013, 11:25:41 PM »

Quote
Not having operated a tube amp before, my knowledge is limited. 
My understanding is that the plate needs to be adjusted for the operating frequency.
You are correct. The amp must be retuned, depending on how much you QSY
and the match that is presented by the change.
Quote
So, assuming my antenna tuner can tame the antenna system to a reasonable SWR (let's say below 1.5:1),
I don't have to worry about tuning the amp,
even if I QSY to a different band???
Yes, you DO have to retune the amp when changing bands,
even if both antennas (or same antenna that works on two bands)
presents a good match. You have to retune the amp (Plate and Load
controls) even if you switch bands while hooked up to a dummy load.
Ken   AD6KA
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W1JTO
Member

Posts: 37




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« Reply #35 on: November 18, 2013, 12:45:29 PM »

Just curious, what happened to:

"Best solid state linear for a newbie"

He is probably so far wrapped around the axles he will need Valium

Sorry....   Was taking a Valium nap  :-)

I purchased the Tokyo-HP 1.5K amp and the matching new 1500 tuner (SN 006 !)  couldn't be more happy with the customer support (outstanding !!!!)   or the units (works of art).

73

John

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KD8MJR
Member

Posts: 2057




Ignore
« Reply #36 on: November 18, 2013, 02:03:45 PM »

Good Purchase, it's probably the best built amp on the market and it's simple to use and very reliable.
You will get many good years of service from it.

Congratulations.

Robert
KD8MJR
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K7KBN
Member

Posts: 2763




Ignore
« Reply #37 on: November 18, 2013, 05:44:51 PM »

Depends on the bandwidth of the antenna.  Generally the lower the frequency (80 and 160 meters), just 10 KHz might require retuning.  On 20 and above, 50-100 KHz wouldn't be unusual.  You can sweep your antennas with something like the MFJ-259B and see what the 2:1 bandwidth, or 3:1 bandwidth is.

Let me see if I understand this correctly...

Since a dummy load has a relatively wide bandwidth, does that mean if I'm firing a tube amp into a dummy load, I can QSY from 160m to 10m without tuning the amp?

Likewise, does it also mean that if I have an automatic antenna tuner between the amp and the antenna, I don't have to tune the amp between bands?

I'm confused...

Question 1:  Normally yes.  Manufacturers' specifications for dummy loads tell what you need to know about the bandwidth of your particular DL.

Question 2: I suspect that would depend on the capabilities of the matching network

Not having operated a tube amp before, my knowledge is limited.  My understanding is that the plate needs to be adjusted for the operating frequency.  However, based on above response, that does not seem to be the case, as long as the antenna system is at resonance.

So, assuming my antenna tuner can tame the antenna system to a reasonable SWR (let's say below 1.5:1), I don't have to worry about tuning the amp, even if I QSY to a different band???

AD6KA gives good advice.  Understand also, however, that "resonance" occurs only at one frequency.  You have to tune the amplifier to that frequency.  With variable capacitors and variable or switched inductors, there are a large number of L and C combinations that you can select, but very few that will "work".  Generally the lower the frequency, the higher the L has to be.
Logged

73
Pat K7KBN
CWO4 USNR Ret.
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