1626, VT-137 triode, anyone homebrew this tube?

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War Bird Radio
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1357
Jan Thu 01, 1970 12:00 am
Amarillo, TX

1626, VT-137 triode, anyone homebrew this tube?

Post by War Bird Radio »

Just curious if anyone has used the 1626 in any homebrew projects?
Tube data http://www.r-type.org/pdfs/1626.pdf" -="window.open(this.href);return false;

I picked up 21 NOS 1626 Hytron tubes at a swap meet earlier this year for next to nothing.
All still boxed and dated 1943 and 1944.

Here's a couple out of the bunch.

Image
hwhall
Member
1967
Jan Sat 25, 2020 4:23 am
Colorado Springs, CO 80917

Re: 1626, VT-137 triode, anyone homebrew this tube?

Post by hwhall »

Oscillator tube in the WWII Command set transmitters.
I wouldn't mind having a couple, or even just boxes, for a museum scene.
Mr. Detrola
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Jan Thu 01, 1970 12:00 am
Detroit, Michigan, USA
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Re: 1626, VT-137 triode, anyone homebrew this tube?

Post by Mr. Detrola »

If you have a ham license it would make a fun QRP transmitter build.

Not very much gain, so not very useful as an audio amplifier or as an audio output stage, although you could probably coax half a watt out of it or maybe close to a watt with 2 of them in P-P.

It's a tube which Heathkit and perhaps others would have used in unconventional applications back in the day when they were available by what seemed like the millions for next to nothing. As one example, Heath used it as a rectifier in test equipment.
Dennis

Experience is what you gain when the results aren't what you were expecting.
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War Bird Radio
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Jan Thu 01, 1970 12:00 am
Amarillo, TX

Re: 1626, VT-137 triode, anyone homebrew this tube?

Post by War Bird Radio »

Dennis,
I like the idea of a P-P TX. Might have to throw something together ala Frank Jones.

I think Heathkit also used two 1626s in the K2 All Band Receiver, one for detector and one rectifier.
Maybe a two step regen using 1626s as both detector and AF to go with the P-P TX!



Edited to correct typo.
Last edited by War Bird Radio on Oct Sun 29, 2023 3:40 pm, edited 1 time in total.
hwhall
Member
1967
Jan Sat 25, 2020 4:23 am
Colorado Springs, CO 80917

Re: 1626, VT-137 triode, anyone homebrew this tube?

Post by hwhall »

I think Heathkit also used two 1625s in the K2 All Band Receiver, one for detector and one rectifier.
Maybe a two step regen using 1625s as both detector and AF to go with the P-P TX!
You meant 1626. 1625s would be really "impressive" in a regen!!! :shock: :D
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War Bird Radio
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1357
Jan Thu 01, 1970 12:00 am
Amarillo, TX

Re: 1626, VT-137 triode, anyone homebrew this tube?

Post by War Bird Radio »

Error noted and corrected. Thanks!

But a 1625 or 807 regen is very doable. There's a guy on ebay and Etsy selling such regns for a number of years now.
https://www.etsy.com/listing/1021539791 ... e_21&frs=1" -="window.open(this.href);return false;
hwhall
Member
1967
Jan Sat 25, 2020 4:23 am
Colorado Springs, CO 80917

Re: 1626, VT-137 triode, anyone homebrew this tube?

Post by hwhall »

But a 1625 or 807 regen is very doable.
Madness, I say! Sheer madness!! :wink:
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shinkuukan
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Dec Sun 14, 2008 2:33 pm
TOKYO JAPAN

Re: 1626, VT-137 triode, anyone homebrew this tube?

Post by shinkuukan »

From just eyeballing the RCA curves, it seems the 1626 has an Rp of about 3K, Gm about 1700 mmho. That is, at typical high plate voltages. At low plate voltages, which you would need for a regen detector, the Rp would probably fall to maybe 2K (or less), mu staying about the same 5, Gm rising to 3000~4000 mmho. Hard to be more precise, the curves are too coarse at low plate voltage and current. Still, it would make a fine regenerative detector, not much audio gain, but very smooth regeneration control. Expect B+ around 15~20VDC. If you figure the realistic audio gain of a 1626 to be about 3, you'd need at least two of them to give you adequate high Z headphone volume. Most important, a three or four 1626 radio would really look the part.

Rob
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Sal Brisindi
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Jan Thu 01, 1970 12:00 am
Freehold, New Jersey 07728
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Re: 1626, VT-137 triode, anyone homebrew this tube?

Post by Sal Brisindi »

I built a nice 3/4 watt stereo amplifier with the 1626 tubes. Sounds amazing with high efficient speakers... do a search on the Darling amplifier. To see the amp I built, click https://www.audioasylum.com/messages/tu ... arling-amp" -="window.open(this.href);return false;

Sal
Need capacitors, resistors and other parts--> http://www.tuberadios.com/capacitors
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Mike Toon
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Jan Thu 01, 1970 12:00 am
Burbank CA

Re: 1626, VT-137 triode, anyone homebrew this tube?

Post by Mike Toon »

Very neat construction. Good going.
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War Bird Radio
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1357
Jan Thu 01, 1970 12:00 am
Amarillo, TX

Re: 1626, VT-137 triode, anyone homebrew this tube?

Post by War Bird Radio »

Sal,
I've seen the Darling amp and it seems to be a lot of work & expense for a low power amp.

I built a 6T9 stereo a while back that was 4 watts per channel. The only thing I bought for the project was the output transformers, everything else I had in the 'ol junk box.

Image
Image

I prefer something RF wise with these tube, like receiver and or CW transmitter.

Frank Jones's Push-Pull CW transmitter is pretty simple and performs well. I've built it using the #53, 6A6 and 6N7 tubes and each had 10 watts out on 80 & 40 mts. Even a 6SL7 will put out 5 watts. Anyway, I'm curious what a pair of 1626 would do. I'll bet more than a couple watts.
Image
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Sal Brisindi
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Jan Thu 01, 1970 12:00 am
Freehold, New Jersey 07728
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Re: 1626, VT-137 triode, anyone homebrew this tube?

Post by Sal Brisindi »

Mike Toon wrote:Very neat construction. Good going.
Thanks!
Need capacitors, resistors and other parts--> http://www.tuberadios.com/capacitors
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Sal Brisindi
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3918
Jan Thu 01, 1970 12:00 am
Freehold, New Jersey 07728
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Re: 1626, VT-137 triode, anyone homebrew this tube?

Post by Sal Brisindi »

War Bird Radio wrote:Sal,
I've seen the Darling amp and it seems to be a lot of work & expense for a low power amp.

I built a 6T9 stereo a while back that was 4 watts per channel. The only thing I bought for the project was the output transformers, everything else I had in the 'ol junk box.

Image
Image

I prefer something RF wise with these tube, like receiver and or CW transmitter.

Frank Jones's Push-Pull CW transmitter is pretty simple and performs well. I've built it using the #53, 6A6 and 6N7 tubes and each had 10 watts out on 80 & 40 mts. Even a 6SL7 will put out 5 watts. Anyway, I'm curious what a pair of 1626 would do. I'll bet more than a couple watts.
Image
I know, I was curious how it sounded. I built 2 of them and sold one of them to a very happy customer.

Sal.

PS, I gathered up most of the parts to build the 6T9 tube amp but I never got to it.
Need capacitors, resistors and other parts--> http://www.tuberadios.com/capacitors
ACORNVALVE
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Jan Wed 15, 2020 11:29 pm
Queensland, AU

Re: 1626, VT-137 triode, anyone homebrew this tube?

Post by ACORNVALVE »

The 1626 appears similar in its physical proportions and power ratings to half a 6N7 double triode. Though the Class C specs are not that helpful comparing the two, but they are basically both 5 Watt triodes although the 1626 has a low amplification factor.

The 6N7 has been used in a number of audio amp circuits over many years, you could use two of these tubes in its place, with the correct heater voltage of course and probably some bias adjustment.
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err ducks
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986
Mar Wed 26, 2008 2:06 pm
Cave Springs AR

Re: 1626, VT-137 triode, anyone homebrew this tube?

Post by err ducks »

hwhall wrote:
I think Heathkit also used two 1625s in the K2 All Band Receiver, one for detector and one rectifier.
Maybe a two step regen using 1625s as both detector and AF to go with the P-P TX!
You meant 1626. 1625s would be really "impressive" in a regen!!! :shock: :D
One 1625 Regen coming up! (12V Space charge, 2 band SW, cathode tap.)
1625regen.jpg
Mark
N0BST
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1585
Jan Thu 01, 1970 12:00 am
Cambridge MN

Re: 1626, VT-137 triode, anyone homebrew this tube?

Post by N0BST »

Talk about using a sledgehammer to kill a gnat! Love it.

Scott Todd
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