TAD "small bottle" 6L6 WGC STRs and JJ KT77s in Renegade

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Resonant Alien

Resonant Alien

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WOW. I had been running TS 5881s and JJ KT66s in my Renegade for some time now, and really liking that combo. But Buckeyedog hooked me up with a pair of JJ KT77s, and man, I am really loving those tubes, especially on Ch 2. So far, it's the perfect middle ground between EL34s and 6L6s for my ears. The KT66s still have a cool vibe, but the KT 77s cover more ground. I put a Chinese 12AX7 in V3 of Ch2 and put a GT ECC83 in V4 (only b/c I had it lying around) - seemed to really thicken things up a bit.

And while I was in there, I decided to try my TAD 6L6 WGCs again (the small bottle ones). Last time I tried them, I biased them the same as the TS 5881s, and ended up preferring the TSs. But since the TADs are 30W tubes vs. the 23W of the TSs, I cranked up the bias on them, and now they are really singing, especially for Ch 1. I also changed V1 in Ch 1 to a JAN/Philips 5751 and V2 to a TS 12AX7. So far, I'm really loving this combo. :thumbsup:
 
:thumbsup: Gotta love it when you find a great tube combination!! :rock:
 
Resonant Alien":9ajyvksb said:
WOW. I had been running TS 5881s and JJ KT66s in my Renegade for some time now, and really liking that combo. But Buckeyedog hooked me up with a pair of JJ KT77s, and man, I am really loving those tubes, especially on Ch 2. So far, it's the perfect middle ground between EL34s and 6L6s for my ears. The KT66s still have a cool vibe, but the KT 77s cover more ground. I put a Chinese 12AX7 in V3 of Ch2 and put a GT ECC83 in V4 (only b/c I had it lying around) - seemed to really thicken things up a bit.

And while I was in there, I decided to try my TAD 6L6 WGCs again (the small bottle ones). Last time I tried them, I biased them the same as the TS 5881s, and ended up preferring the TSs. But since the TADs are 30W tubes vs. the 23W of the TSs, I cranked up the bias on them, and now they are really singing, especially for Ch 1. I also changed V1 in Ch 1 to a JAN/Philips 5751 and V2 to a TS 12AX7. So far, I'm really loving this combo. :thumbsup:
Click to expand...
The wgc's fukin rock in any amp
 
I have KT77 and E34L paired in my RMod100 and luv it.
I have KT88's Gold Lions but prefer the 77's haven't paired them up with anything yet.
 
Yo Resonant Alien

Congrats on the new tubes. Quick question for you. I'm about to re-tube my Renegade head (I'm actually going to put some KT77's in the EL34 side as well based on some recommendations I got from Eurotubes) and I know that a few posts back you were asking some questions about the proper bias numbers, plate voltages, etc. Did you get that all figured out? I've never biased anything and I was wondering, since we have the same amp, if you could offer any advice. I think you mentioned that you were an electrical engineer.

The guys at Eurotubes said that using the external bias test points on the back of the head were REASONABLY accurate but that I might be better off using a bias probe on just one tube at a time. Do you still adjust the bias for both matched tubes using one trim pot? Thanks in advance. I thought you might be the guy to ask about this.......
 
jdsjw13":17vbo0k9 said:
Yo Resonant Alien

Congrats on the new tubes. Quick question for you. I'm about to re-tube my Renegade head (I'm actually going to put some KT77's in the EL34 side as well based on some recommendations I got from Eurotubes) and I know that a few posts back you were asking some questions about the proper bias numbers, plate voltages, etc. Did you get that all figured out? I've never biased anything and I was wondering, since we have the same amp, if you could offer any advice. I think you mentioned that you were an electrical engineer.

The guys at Eurotubes said that using the external bias test points on the back of the head were REASONABLY accurate but that I might be better off using a bias probe on just one tube at a time. Do you still adjust the bias for both matched tubes using one trim pot? Thanks in advance. I thought you might be the guy to ask about this.......
Click to expand...

Well, I am not THE expert on this, but I did end up using the logic/method I asked about in that post. The JJKT77s are 25W tubes, and the plate voltage on the Renegade is "about" 460VDC according to Bruce, so the math works out to 54mA max,or 38mA at 70%, so I biased the KT77s at 38mA per tube, which corresponds to a reading of 76mV at the Renegade bias point, since it is across both tubes. The TAD 6L6WGC are 30W tubes, so their max current would be 65mA max or 45mA at 70%, so I biased them to 45 mA each, or 90mV at the bias point.

So far, nothing has exploded and the amp sounds great with this config, so I'm keeping it like this for now.

As far as using the Renegade bias point vs. buying a bias probe and doing it per tube - I dunno - most recommendations I've seen say to set the bias anywhere from 50 to 80% of the tubes max dissipation, so as long as the Renegade points are reasonably accurate, I think it would be good enough for most people. I don't think Bruce would put them on there if they weren't pretty close to accurate.
 
Awesome!!! Thanks for your help, it makes sense and helps me out a lot. I'm looking forward to hearing these KT77's....
 
I have a pair of KT77 I could try out.

does the Renegade has external bias points? how should I bias them?
 
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