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Author Topic: Best way to pack a HW-101 for shipment  (Read 28475 times)
KB1WSY
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« Reply #15 on: September 15, 2014, 10:26:26 AM »

I don't know what those output tubes are, but if they had top caps, they would look like a fair number of 1930's transmitting tubes....

They are AA62Bs, described as "the largest single plate DHT available today. We like to call her the 'Queen of Single Ended Triodes'." (http://www.lauferteknik.net/electronics/ayonaudio/aa62b.htm).

I find Her Royal Highness rather ugly. Give me a KT-66 any time!



OK, the '66 is a tetrode, but you know what I mean.

73 de Martin, KB1WSY
« Last Edit: September 15, 2014, 10:44:49 AM by KB1WSY » Logged
G3RZP
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« Reply #16 on: September 15, 2014, 12:55:43 PM »

What, pray, is a "DHT"?
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KB1WSY
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« Reply #17 on: September 15, 2014, 03:08:28 PM »

What, pray, is a "DHT"?

Not sure, but according to one "acronym dictionary" it's "Directly Heated Triode." Could that really mean that this thing doesn't have a cathode?

Casual googling finds that you can buy one of these royal babies, hyped as "the Bugatti of audio," for 1,395 NZ dollars (1,140 USD) -- http://www.audioreference.co.nz/product/ayon-aa62b-s-reference-triode-power-tube-queen-single-endedsbased-we300b. Financing is available! Take out your mortgage now!

I still think it's ugly. In fact, the Bugatti analogy is particularly inappropriate.

73 de Martin, KB1WSY
« Last Edit: September 15, 2014, 03:12:33 PM by KB1WSY » Logged
AC5UP
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« Reply #18 on: September 15, 2014, 05:24:33 PM »

Apparently only a select few among us recall the earliest of tubes like DeForest's Audion used a directly heated cathode... 
The 2A3 is well regarded among audiophiles by virtue of its extreme simplicity. No screen grids to get between you and
the music, it's like half of a 5U4 but with a grid so it can amplificate:



Then, you may ask, how does one utilize a device like this?  Observe.........



The filament is grounded through an R/C network much like a 6V6 cathode, but with the addition of a 100 Ohm potentiometer adjusted with great care to the null of the filament voltage.
The concept is so exquisitely ancient it's like drinking the primordial (triodial) soup of audio.........    Roll Eyes
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G3RZP
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« Reply #19 on: September 16, 2014, 01:06:57 AM »

'5UP,

Surely that circuit would give poor results with all those electrolytic capacitors? It's well known that using electrolytic capacitors gives 'electrolytic sound' because of their 'poor sonic performance'. You need silver foil/paper capacitors to avoid that (preferably rolled on the thighs of young far Eastern women for best sound) ....plus the pins on the plug into the power line need to be gold plated and all wiring in oxygen free copper.....and transformers wound with silver wire - including the power transformer.

2A3s or their 6volt equivalent, the 6A3 (or 6B4 on an octal base) were really good for the series regulator in stabilised power supplies. Not quite as good as a 6AS7 or 6080, though. Are those popular with audiophools?
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AC2EU
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« Reply #20 on: September 16, 2014, 06:50:59 AM »

This thread has wandered way off the original question of the best way to pack a HW-101. I guess the consensus for the best way to pack that rig is in a dumpster?
Anyway, I'll add to the digression about toob audio to mention that the schematic shows 2A3s, why not go all the way and use an 80 rectifier too? I mean, a 5U4 is modern technology for god's sake!  Grin

It baffles me that some people believe that 100 year old tube technology is somehow superior.
Maybe they should try the crank-up Victrola that has none of that nasty modern technology between the needle and and the horn! Certainly,that MUST be the ultimate in sound!!!  Roll Eyes
Then again, it can't be any good because a Victrola can be found in Grandma's attic for free. Deforest tech must be better since specialty companies produce it and charge thousands of dollars for it.
Ah, the power of Advertizing.
PT Barnum was right!
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G3RZP
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« Reply #21 on: September 16, 2014, 01:40:12 PM »

A 5U4 has a higher current rating than an 80 (which is really a UX4 based 5Y3G). For historical accuracy, you would use a 5Z3G, which is a 5U4 on a UX4 base. Or maybe even an 83, which is a mercury vapour equivalent!
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AC2EU
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« Reply #22 on: September 16, 2014, 03:13:53 PM »

A 5U4 has a higher current rating than an 80 (which is really a UX4 based 5Y3G). For historical accuracy, you would use a 5Z3G, which is a 5U4 on a UX4 base. Or maybe even an 83, which is a mercury vapour equivalent!
That's a single 2A3! the 80 can produce twice the required current. I just looked them up because  I have an old 1920's Seeburg Juke box that uses an 80 to power 2A3s in push -pull. There would be no sag either way.
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G3RZP
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« Reply #23 on: September 17, 2014, 12:56:03 AM »

I think an 80 would be pushed in that circuit, because the reservoir capacitor is rather large. The published ratings for the 80 are for a 10 mFd reservoir. So that is probably why they went for a 5U4 - if there was a logical reason. There isn't always.....Plus the fact that the circuit suggests that there is a left hand amplifier powered from it as well

Look at the 2A3 plate with its series 50 ohm 10 watt resistor. The 2A3 doesn't need a 10 watt resistor there unless they are expecting flashovers - so why 10watts? Same with the cathode bias resistor....

I didn't know 417As were still available.....time was when that was THE tube for the front end of a 2 metre converter!

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AD5IW
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« Reply #24 on: September 18, 2014, 05:24:05 AM »

This thread has wandered way off the original question of the best way to pack a HW-101. I guess the consensus for the best way to pack that rig is in a dumpster?


Well the HW-101 made it ok.  The seller packed the radio strangely though - inspite of my advice.  He did wrap bubble wrap around the radio - about 2" thick (which saved it).  Then he put it in the box with foam peanuts.  To keep the radio centered, he put 4 small boxes on each side of the radio.  Anyway it made it with out tube breakage or front panel damage.

Took it apart and looked it over.  It looks like it was built by the factory or a professional - the solder job is excellent, wires zip tied, everything done as per the manual.  Found a burnt resistor - a 100 ohm that ties the B+ voltage to plate driver board.  It looked like it had rubbed up against a metal divider.

I quickly replaced it and hooked it up to my (known good) power supply with a variac.  Slowly dialed the variac up from 0 zero volts.  At about 15 volts, smoke comes curling out of the radio.  Ugh.

It was that same 100 ohm resistor that I had replaced.  Did a quick check and found the resistance to ground on that B+ wire was 60 ohms!  It is supposed be open.  Hmm that would be a lot of current for a 1 watt resistor.  Spent an hour unsoldering and removing the plate driver circuit board.  Once it was out, it was easy to see a scorched mica capacitor.  Unsoldered it and cleaned up the pc board.

The mica capacitor was a 680 pF rated at 350 volts.  Looked at all the other mica caps on the board - they were rated at 500 volts!   No wonder that it burnt up.  Someone made an assembly error long time ago.

Replaced the mica cap and the 100 ohm resistor and powered up again (after some resistance checks).  Voila!  It works.  But what a dog it was.  It is nowhere as good sounding, sensitive, stable or as selective as my old hw-100.  Now I can understand the hater comments.  Smiley

Of course it needs a tune up and all the updates.  All I can say is what a lot of fun this has been.
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AC2EU
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« Reply #25 on: September 18, 2014, 07:06:21 AM »


I'm glad you got it going. However, those Phenolic boards are trouble.
As a kid, I was too poor to even have a Heathkit dream, so I am completely immune to the urge to collect them now.
As an objective observer, I see those boards and the "two piece" design and I am immediately turned off. The belts have a tendency to slip and/or break, too. I've see other Heathkits that were separate rx/tx units with with all kinds of interconnections,etc, which made me scratch my head and ask why?  I guess that puts me in the "hater" category, but I thought I would mention some reasoning behind the negativity.

Hey, if a HW-101 gives you that warm and fuzzy feeling, I'm happy for ya! That's what a hobby is all about!

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N3QE
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« Reply #26 on: September 18, 2014, 10:43:12 AM »

I don't know what those output tubes are, but if they had top caps, they would look like a fair number of 1930's transmitting tubes....

I think they are "Ayone AA62B"'s which is some kind of audiophool WE 300B variant.

Yes, with a top cap and less severe taper, it's kinda like the 814 tube:



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N8CMQ
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« Reply #27 on: September 20, 2014, 05:55:21 PM »

Tubes are a waste, get new replacements.
If you have a local source, support them,
or http://www.rell.com/products/Electron-Tubes-Vacuum-Devices.html
I have used Richardson for 30+ years, good people and good tubes.

N8CMQ Jeff
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N8CMQ   Jeff Retired...
AC5UP
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« Reply #28 on: September 20, 2014, 07:58:20 PM »


I guess that puts me in the "hater" category, but I thought I would mention some reasoning behind the negativity.

I don't see it as hate, I see it as the logical conclusion of a well reasoned and fact based investigation... 
Why rely on some nameless assembly line worker to create cold solder joints when you can do it yourself?

BTW:  IMHO the most beautiful of the 8xx series power tubes is the 837:



If I made a hollow state pinup calender you'd see 837's on the beach, in the park, at the ski resort, poolside with their Ray-Bans.

Yowser, what a tube!!
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G3RZP
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« Reply #29 on: September 21, 2014, 01:17:15 AM »

837 - Almost a little brother to the 1625
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