I will try that 15k later tonight when I get a chance. I put the 5751 in V1 and played for a while. Sounds really warm, but the drop in gain and different character takes away from the chime a bit and it is noticeably less gainy. Not sure if I like it yet or not. I also tried a new New Sensor Mullard, which sounds really good. When I get a chance to sit down and play a little later, I will roll a few more tubes through there to see what I like. I have a NOS Telefunken that I will try in there as well.
-
We are looking to make improvements to the Classifieds! Help us determine what improvements we can make by filling out this classifieds survey. Your feedback is very appreciated and helpful!
Take survey
Traynor YBA-1 at high plate voltage
- Thread starter Csquare4
- Start date
This site may earn a commission from merchant affiliate links like Ebay, Amazon, and others.
I will try that 15k later tonight when I get a chance. I put the 5751 in V1 and played for a while. Sounds really warm, but the drop in gain and different character takes away from the chime a bit and it is noticeably less gainy. Not sure if I like it yet or not. I also tried a new New Sensor Mullard, which sounds really good. When I get a chance to sit down and play a little later, I will roll a few more tubes through there to see what I like. I have a NOS Telefunken that I will try in there as well.
Also, if you'd be so kind, I'd also LOVE to see the voltages on pins 1 and 6 of each preamp tube once that 15k is in there.
-Lane
mickeydg5
Well-Known Member
- Joined
- Sep 30, 2011
- Messages
- 28,591
- Reaction score
- 16,369
Taking notes Lane?
He, he.
That is good reference information.
He, he.
That is good reference information.
Taking notes Lane?
He, he.
That is good reference information.
Heh heh. Well...not so much that as the fact that I want to make sure that -after all of this voltage dropping- he's still got decent enough levels in the preamp!
-Lane
mickeydg5
Well-Known Member
- Joined
- Sep 30, 2011
- Messages
- 28,591
- Reaction score
- 16,369
Yes, that is common place Bassman and JTM stuff and the voltages should follow suit.
We are going to have to wait until tomorrow, my son hijacked my bench for a school science fair project he is working on and I had to pack my amp up to get it out of his way for the time being. Then I got sucked into troubleshooting his project with him.
I will tell you what the voltages were when I measured them this afternoon after doing the zener drop with the current 10k 1W resistor in R32.
V1:
1 244
2 0.0
3 1.76
6 245
7 0.0
8 1.76
V2:
1 360
2 207
3 208
6 207
7 0.0
8 1.2
V3:
1 274
2 30
3 38
6 280
7 29
8 38
I will get back to this once I get a chance to swap that resistor.
Heh...no I wish! I don't even know anybody around me with a tube tester anymore. I used to be good friends with a Ham that had one, but he moved away. Now I fly blind when it comes to tube testing. My usual way with 12AX7's and the like it to plug them into an old Hammond build that I did which is based a little on the 18W, and see how they sound.
I would love to try these 7027A's out though...I just don't have the balls at this point, lol.
mickeydg5
Well-Known Member
- Joined
- Sep 30, 2011
- Messages
- 28,591
- Reaction score
- 16,369
I am interested as well to see what the 15k will do to all the voltages. It should fall in line nicely I believe.
Hey guys, I finally had a chance to get back at it. I replaced the 10K R22 with an NOS Carbon Comp resistor that metered at 16.5K. Probably more than I wanted, but that is all I had in the bin. I dropped the plate voltages down quite a bit on the low signal tubes, maybe even too much as I lost a little spank. I ordered some Metal Film 12k and 15k 1% to play with it a bit, but they won't be here before the weekend.
Anyways, here are the latest on the voltages. Still holding steady in the mid 450's on the B+, so the zener dropping network seems to still be working.
V1:
1 189
2 -
3 1.52
6 195
7 -
8 1.52
V2:
1 286
2 164
3 165
6 164
7 -
8 1.01
V3:
1 218
2 24
3 30
6 220
7 23
8 30
V4:
4 453
5 456
6 -45
8 41.1 (thru 1R 1%)
V5:
4 453
5 456
6 -45
8 42.1 (thru 1R 1%)
So I am still biased up at just over 60% dissipation, I may bump that up a little. The JJ 7027a's actually sound pretty good, but I have a couple sets of =C= 6L6GC's that I might try as well. I want to replace that R22 with the metal film before I start playing with the tubes to see if I can get a little more bite back from the pre-amp side of things.
Overall, the amp is really pretty quiet. Very minimal hum and hiss, certainly as good as my JTM45 clone. So there it is.
Craig
STOP!
IMHO, the voltages are PERFECT. You don't need more.
You're done.
Now crank to taste and enjoy...you've earned it!
-Lane
IMHO, the voltages are PERFECT. You don't need more.
You're done.
Now crank to taste and enjoy...you've earned it!
-Lane
STOP!
IMHO, the voltages are PERFECT. You don't need more.
You're done.
Now crank to taste and enjoy!
-Lane
Ha ha! Ok sounds like a plan
Btw, Mickey asked me about the original CGE 7027A tubes. I went ahead and put them in the amp, fired it up through a current limiter lightbulb -- dim glow -- so all was well. I took that out of the way and turned it on, monitoring the plate and screen voltages and they pretty much were right where there are with the new JJ's. I biased it up at 455V at 38mA and 44mA and decided to play it a little. Obviously, these old tubes are not matched as well as the JJ's, but they really do sound sweeter at mid-volume with the same tone settings. Much mellower on the bright channel with a smoother more defined low end. I would say the response curve is probably a little flatter across the band than with the JJ's which seem to have a little more brittle high end and boomier bottom. Probably I need to dial it in a bit, but yeah, I think these sound really good being that they were the original tubes.
Now to decide, lol, keep them in or go back to the new production tubes? I will probably let my son jam with it and do a blind test to see what he thinks.
mickeydg5
Well-Known Member
- Joined
- Sep 30, 2011
- Messages
- 28,591
- Reaction score
- 16,369
Just happened to be looking and saw the new post. Those are decent voltages, like Lane pointed out.
I do not recall if you said that 6L6GC tubes have been tried. I do not know how Traynor wired the sockets and components, but keep in mind that the 7027 and 6L6 have some different internal connections. You do not want to fizz anything out!
You can rotate the two CGE 7027A tubes to see if the bias gets any closer ( if you have not tried already).
Either set of those output tubes with the voltages that have been posted can be bised up to 48mA. Your preference, see what you like.
I do not recall if you said that 6L6GC tubes have been tried. I do not know how Traynor wired the sockets and components, but keep in mind that the 7027 and 6L6 have some different internal connections. You do not want to fizz anything out!
You can rotate the two CGE 7027A tubes to see if the bias gets any closer ( if you have not tried already).
Either set of those output tubes with the voltages that have been posted can be bised up to 48mA. Your preference, see what you like.
Yes, I haven't tried the 6L6GC's yet, but the way that Traynor wired the tube sockets left pins 1 and 6 open, so they should be an exact replacement.
Good idea on swapping the output tubes, I will try that and see what I come up with. I will also bias it a little hotter and see how they sound. However, if it gets any more lush I might just pee myself
Thanks again for all the help guys. I really appreciate you both taking the time to hang with me on this thread.
