Trace Elliot Twin Valve Combo Tube Compliment

[conttador]

I bought a 115 TwinValve combo from Europe which arrived today. Unfortunately/fortunately one of the power tubes was broken in transit. I say Fortunately because everything else is fine.

That being said, do you guys know what the the tuvb compliment is on this amp?

Any one roll tubes on one of these? I figured I’ll just take it in and have it checked out and while I’m at it replace all the tubes. I have some Telefunken 12ax7s that I pulled from an old HH Scott amp but I’m not sure if those would work on this amp.

if you’ve rolled tubes one of these I’d love to hear what you tried and your thoughts on the outcome.

 

[Wasnex]

I assume you mean Trace Elliot Twin Valve. Service Manual attached. I suggest you download and save it, as they are getting harder to find out in the open on the internet.

The preamp is solid state (no tubes).

Output tubes are a pair of 6550s. The schematic does not show a bias adjustment; so you will need a pair of tubes graded to work in the amp, or a technician may need to change a resistor in the bias supply to get the tubes to run properly.

The power amp also has a pair of ECC83...This is an alt name/sub for 12AX7, 7025

I have not played this amp, but the power amp is pretty much the same as the later Trace Elliot V-Types. I rolled tubes in my V-Type and the small signal tubes in the power amp were not very responsive to tube rolling. I left the original TE tubes in these positions.

While you can try a Telefunken, I would be surprised if it makes enough difference to leave such a valuable tube in the amp.

 

[conttador]

I assume you mean Trace Elliot Twin Valve. Service Manual attached. I suggest you download and save it, as they are getting harder to find out in the open on the internet.

The preamp is solid state (no tubes).

Output tubes are a pair of 6550s. The schematic does not show a bias adjustment; so you will need a pair of tubes graded to work in the amp, or a technician may need to change a resistor in the bias supply to get the tubes to run properly.

The power amp also has a pair of ECC83...This is an alt name/sub for 12AX7, 7025

I have not played this amp, but the power amp is pretty much the same as the later Trace Elliot V-Types. I rolled tubes in my V-Type and the small signal tubes in the power amp were not very responsive to tube rolling. I left the original TE tubes in these positions.

While you can try a Telefunken, I would be surprised if it makes enough difference to leave such a valuable tube in the amp.

Thank you for the feedback!

Do you know it KT88s would work in lieu of the 6550s? Is there any advantage to getting some more “expensive” power tubes? I did a quick search on eBay and saw that there’s Tekefunken and other Russian brands too.

Thanks again, appreciate the feedback and thanks for the service manual!

 

[Wasnex]

Thank you for the feedback!

Do you know it KT88s would work in lieu of the 6550s? Is there any advantage to getting some more “expensive” power tubes? I did a quick search on eBay and saw that there’s Tekefunken and other Russian brands too.

Thanks again, appreciate the feedback and thanks for the service manual!

I would be surprised if there is any problem running KT88, as long as the amp is properly biased.

As I mentioned the output section is almost identical to the later V-Type amps. V-Types came stock with KT88.

The schematics indicate the factory bias is -42V. It's better to measure tube current and set the bias to the proper current range, rather than simply setting the bias to -42V.

The V-Types had variable bias control. A tech could add a bias control. If you like, I will PM the V4 service manual, which shows how the bias controls are wired.

I would not go overboard on super expensive NOS tubes. Buy quality tubes from a reputable vendor who does a burn in and has good testing and matching procedures.

 

[conttador]

I would be surprised if there is any problem running KT88, as long as the amp is properly biased.

As I mentioned the output section is almost identical to the later V-Type amps. V-Types came stock with KT88.

The schematics indicate the factory bias is -42V. It's better to measure tube current and set the bias to the proper current range, rather than simply setting the bias to -42V.

The V-Types had variable bias control. A tech could add a bias control. If you like, I will PM the V4 service manual, which shows how the bias controls are wired.

I would not go overboard on super expensive NOS tubes. Buy quality tubes from a reputable vendor who does a burn in and has good testing and matching procedures.

Thanks again. I’ll go with sone decent tubes then. I have a V4 that needs to be looked at, I bought it NOS and it blew a fuse a few weeks ago so that manual will come in handy.

 

[Wasnex]

Thanks again. I’ll go with sone decent tubes then. I have a V4 that needs to be looked at, I bought it NOS and it blew a fuse a few weeks ago so that manual will come in handy.

If the V4 was truly NOS, it could need a cap job. The amp was most likely made in the mid to late 90s. The power supply has several electrolytic capacitors, and they need to be powered up from time to time, or the dielectric can break down.

The Tech Manual and Operation Manual are attached.

 

[conttador]

If the V4 was truly NOS, it could need a cap job. The amp was most likely made in the mid to late 90s. The power supply has several electrolytic capacitors, and they need to be powered up from time to time, or the dielectric can break down.

The Tech Manual and Operation Manual are attached.

I remembered I had some extra KT88s that I got when I bought another tube amp here. I dropped them in crossed my fingers and powered up the amp and it worked!

I’ll still take it in since I don’t know if it was being played regularly or if it had been sitting a while. Everything looks nice & clean but still not taking any chances.

Thanks again for all the insight and literature!

 

[KF2B]

Old thread, but so is the amp

Mine has been having some issues lately: sounds wonderful when firing up, but the sound worsens after a couple of songs – volume does not drop, but the sound flattens; it is like the bass thins and the overall sound loses dimensionality. I wonder if it is the pair of 6550s or the 12ax7s? Or is it in need of new capacitors or what??? All help is much appreciated!

 

[Wasnex]

Mine has been having some issues lately: sounds wonderful when firing up, but the sound worsens after a couple of songs – volume does not drop, but the sound flattens; it is like the bass thins and the overall sound loses dimensionality. I wonder if it is the pair of 6550s or the 12ax7s? Or is it in need of new capacitors or what??? All help is much appreciated!

It could be a lot of things. My advice is take the amp to a qualified electronics tech.

I'll attach a copy of the SVC manual.

 

[KF2B]

I'll attach a copy of the SVC manual.

Thanks, much appreciated! Yeah... Will take it to a pro. Never hurts to have a service and see if capacitors, etc are up to their job.

 

[agedhorse]

Just a reminder that 99% of all caps replaced are perfectly fine and are done so just to make a customer feel good.