Can I Use 6L6GC tubes instead of EL34 tubes ???? Peavey Windsor Head

[CoopDaKill]

Hi,
Guys,
Still having RF oscillation issues with this Peavey Windsor head. I've had it parked for several months, but I'm getting ready to start digging in it again. The scematic says, "EL34/6L6GC. So I take it that I can use either/or, Right? With no bias adjust. This amp has no bias adjust, to my feable recolection.

Just wondering if a faulty tube (preamp or power tube) would cause RF oscillation? I've checked about every other component in the amp. Maybe a bad part if under a working load? IDK.


Thanks in adavance,

[Jazz P Bass]

The EL34 tubes & the 6L6 tubes require a much different bias voltage on pin #5 of the output tubes.
Read this link.
Biasing a Peavey Windsor.
Link: http://music-electronics-forum.com/t13238/

[CoopDaKill]

The EL34 tubes & the 6L6 tubes require a much different bias voltage on pin #5 of the output tubes.
Read this link.
Biasing a Peavey Windsor.
Link: http://music-electronics-forum.com/t13238/

Thanks Jazz P Bass. I'll look into this next week, when I have some spare time. Much appreciated.

[TomCarlos]

Hi guys....

I found this old post and have the same question. So I trying to do some researrch.

I did find other threads on the topic but wanted to read this post - http://music-electronics-forum.com/t13238/

Unfortunately, I cannot access "t13238." Is there a trick to finding old threads?

I also found a thread on the Peavey Forum web site - https://forums.peavey.com/viewtopic.php?t=25686

So the trick here seems to be re-bias the amp to accommodate 6L6GC tubes.

About that old MEF thread # t13238.

Thanks !!

Peavey_Windsor_Schematic_20060718.pdf

[mhuss]

Yes, you normally just have to re-bias as long as the socket connections are OK (i.e., pin 1 connected to pin 8). Hopefully the bias adjustment allows enough latitude, worst case might have to change out one of the series resistors.

[g1]

wanted to read this post - http://music-electronics-forum.com/t13238/

Unfortunately, I cannot access "t13238." Is there a trick to finding old threads?

This is the thread titled 'Biasing peavey windsor' : https://music-electronics-forum.com/...peavey-windsor

[TomCarlos]

Thanks G1 !!

I found that post earlier and have it bookmarked now. I tried looking for the old thread number but to no avail.

[Helmholtz]

What exactly is your problem/question/intention?

[TomCarlos]

Hello Helmholtz....

A friend has brought me his Peavey Windsor amp. It currently has no tubes. He mentioned when it was played last, it didn't sound all that great. I have no idea what this means.

I asked him if he previously used EL34s or 6L6 tubes and he wasn't sure. That is why I went looking for info on the topic.

I have yet to pull the chassis from the amp to see if pins 1 and 8 on the power tubes are connected. That might be my indicator as to what tubes were in the amp previously.

And perhaps I can ask - has anyone tried out both tubes in this amp and have your "heard" any audible differences? I guess the one advantage to a 6L6 tube is that they seem to be more readily available.

In any event, I wanted to know what I was getting into here before I started looking at the amp.

If I encounter any issues with the amp, I will open a new post.

Much appreciated !!

[Helmholtz]

When you get the amp measure the bias voltage at the test point (P29) without power tubes.
If between -40V and -45V it was biased for EL34s. 6L6s want something around -55V.
With tubes in adjust for an idle cathode current around 35mA per tube.

Of course worn tubes can make any amp sound bad no matter which type.

[35L6]

I'm almost understanding this circuit . They have the bias connected to the surpressor grid . Don't know what that does for EL34 operation . With 6L6 g3 is connected to the cathode and ground . That puts the four 10k resistors in parallel for 2k5 and that is parallel with the 39k in the bias circuit . That doesn't seem right . What's up with this thing ?

[g1]

With 6L6 g3 is connected to the cathode and ground . That puts the four 10k resistors in parallel for 2k5 and that is parallel with the 39k in the bias circuit . That doesn't seem right . What's up with this thing ?

Pin1 is floating with 6L6. You are confusing it with g3, they are not the same thing.

[35L6]

That makes much more sense .

[g1]

As for the EL34 operation, connecting the suppressor to negative voltage (rather than ground) is supposed to improve reliability. It is also done that way in some Traynor amps.

[nosaj]

You are confusing it with g3,

That's your grandson, Right?
nosaj