I am picking up an old Traynor YBA-1 MK II and it is specked to use 7027 tubes.
I never heard of those... Can they be swapped out for something more coomon ? EL34 S for example ?
What are 7027 tubes ?
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Ten Over
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Re: What are 7027 tubes ?
Here is what Yorkville (Traynor) had to say about it:
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Stevem
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Re: What are 7027 tubes ?
Here ya go!
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When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: What are 7027 tubes ?
THank you !
That covers It !
That covers It !
Re: What are 7027 tubes ?
Hello --
A 7027A is higher power variant than what's described on the datasheet Steve has shared -- 35W plate dissipation and 600V max plate voltage. Fairly popular in Ampeg bass gear and for a brief era of high end hi-fi. Given market demand there are actually current production versions from JJ and New Sensor (under Tung Sol mark), though there is some justified skepticism about how close to original power specs these really are.
You can find both at :: https://www.thetubestore.com
That said, a fresh set of 6CA7EH is perhaps your best bet, and then simply follow the Traynor modification instructions.
Best ..
A 7027A is higher power variant than what's described on the datasheet Steve has shared -- 35W plate dissipation and 600V max plate voltage. Fairly popular in Ampeg bass gear and for a brief era of high end hi-fi. Given market demand there are actually current production versions from JJ and New Sensor (under Tung Sol mark), though there is some justified skepticism about how close to original power specs these really are.
You can find both at :: https://www.thetubestore.com
That said, a fresh set of 6CA7EH is perhaps your best bet, and then simply follow the Traynor modification instructions.
Best ..
Last edited by didit on Wed Jul 03, 2024 3:39 pm, edited 1 time in total.
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Stevem
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Re: What are 7027 tubes ?
That’s criminal what Tung Sol is getting for those tubes!
That’s really a case of the consumer paying for a name if I ever saw it!
That’s really a case of the consumer paying for a name if I ever saw it!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: What are 7027 tubes ?
A 7027A is pretty much a 6L6GC that was engineered to run at a higher plate and screen voltage. The pinouts are different. The internal components are more rugged and were designed to dissipate the heat and handle the high voltage. The 7027A are spec'd to run at 70% to 80% higher voltages than a 6L6GC. Ampeg V4 (V4-B) amps run them really high. JJ sells what they call a 7027A that is clearly just their 6L6GC that has their pin-outs switched.
People are running these JJ7027A in old V4s successfully. I am one of them. Will they burn out faster than a genuine 7027A? Maybe, but I have not had one fail yet and it has been over 5 years.
People are running these JJ7027A in old V4s successfully. I am one of them. Will they burn out faster than a genuine 7027A? Maybe, but I have not had one fail yet and it has been over 5 years.
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Stevem
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- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: What are 7027 tubes ?
It’s a different tube!
Pin 1 is tied to pin 4 and pin 6 that a 6L6 type does not even have is tied to pin 5.
If I have to, I have used JJ 6L6 outputs in the V4s and there like from Ampeg or the Oliver B200 model like I have after re-wiring the socket and setting the idle current to get 60% dissipation max.
Any other tube that has a DC wattage rating of 35 that you might stuff in will also need a ton more heater current .
This makes the PT run much hotter and in the end drop off available B+ current to the point that you might as well just run 30 watt rated 6L6 and not burn up one of these near impossible to replace PTs in these Ampeg models.
Pin 1 is tied to pin 4 and pin 6 that a 6L6 type does not even have is tied to pin 5.
If I have to, I have used JJ 6L6 outputs in the V4s and there like from Ampeg or the Oliver B200 model like I have after re-wiring the socket and setting the idle current to get 60% dissipation max.
Any other tube that has a DC wattage rating of 35 that you might stuff in will also need a ton more heater current .
This makes the PT run much hotter and in the end drop off available B+ current to the point that you might as well just run 30 watt rated 6L6 and not burn up one of these near impossible to replace PTs in these Ampeg models.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!