? about putting a 6l6 in a champ, same OT?

[Jimmybjj]

... I've seen several post about people putting a 6l6 in a champ and just changing out the bias resistor and cap. I am still pretty ignorant to electroncs and amps but doesn't the 6l6 have an impredance of 4000 ohm's and he 6v6 about 8000. would a stock ot be ok with long term usenof a 6l6? I have a bandmaster OT that has a 4000 ohm primary, can I install this in the champ for use of the 6l6?

[Groover]

I doubt you could fit a Bandmaster OT in a Champ anyway, but it is a push-pull transformer. You need a transformer designed for a single ended power amp.

[stokes]

A transformer only knows turns ratio,if you increase your speaker load to 8 ohms the 8000 ohm primary now becomes 4000 so you will have an "ideal" match.But it really isnt that important,you can safely put a 6L6 in your Champ,rebias and it will be okay.You wont see much difference in output as the 5 watt OT and the circuit driving the power tube will limit it.You may percieve a bit more headroom,but not a whole lot,I've done it,its not that impressive.

[Groover]

I thought using an 8ohm speaker with a Champ OT would cause the power tube to see 2x the primary, not 1/2. Is this wrong?

[Chuck H]

No, that's correct. You'd need to run a 2 ohm speaker in the Champ to reflect a 4k primary to the 6l6. AFAIK there is no such speaker made for guitar amps.

But I too have run a Champ with a rebias and a 6l6 tube. And as noted, it's not that impressive.

Chuck

[Groover]

You could run it into 4 8ohm speakers in parallel or two 4ohm speakers in parallel.

How about a 4-12" Champ combo?

[Gibsonman63]

You would lose some portability witha 4 x 12 combo.

I have a couple of stock Vibro-Champs. They don't get a lot of use, but I can't pass up a screaming deal on an old Fender amp. With an RCA to 1/4" adapter and a speaker cable, you can use them to drive a 4 x 12 Marshall Cabinet. It is much more impressive than you would think it would be. I would think that a Vibro-Champ with a stock tube arrangement, a couple of 8 ohm speakers wired in parallel and a couple of tweaks or tube swaps so you can play right at the edge of breakup (and control it with playing dynamics) would be just the ticket.

[ThermionicScott]

You can buy Champ OTs with a 5K primary tap. Still won't help you make more than 5W or so, but I thought I'd throw that out there. One of those Hammond 125-series would be the ticket...

- Scott

[Jimmybjj]

You can buy Champ OTs with a 5K primary tap. Still won't help you make more than 5W or so, but I thought I'd throw that out there. One of those Hammond 125-series would be the ticket...

- Scott

I saw that triode electronics offered a champ transformer with a 5000 ohm primary (actually I have this one) now my understanding of all of this is still in it's beginning stages. how does having a 5000 oposed to the factory 8000 ohm primary affect the tone and/or power tube?

[ThermionicScott]

I saw that triode electronics offered a champ transformer with a 5000 ohm primary (actually I have this one) now my understanding of all of this is still in it's beginning stages. how does having a 5000 oposed to the factory 8000 ohm primary affect the tone and/or power tube?

It allows the output tube to swing more current for more output power, but it can also increase distortion. For a single-ended amp, that second-harmonic content is part of the sound, so you may like it.

I really need a spectrum analyzer.

- Scott

[Groover]

For what it's worth AES has an inexpensive generic SE OT about Champ OT size with 5k Pri, 8ohm sec.

I ordered one (because I'm broke & Scottish), but the Hammond 125dse or 125ese are beefier, and would probably help out the low end more and handle more current.