Clean 15-20 watts

[Firestorm]

Build in more power than you'll ever use and it will stay totally clean at the desired operating level. I once built an amp for a jazzer who wanted clean but with mids (which are typically scooped). Gutted a Fender 135, and used 2 KT88s plus 2 6L6GCs. It could probably do 150W, buy he never gets it past 40 is my guess.

[LeftyStrat]

I've experienced this problem. Basically wanting something between a 6V6 and a 6L6 based amp. The 6L6 doesn't break up at all at band volumes, but the 6V6 breaks up too early. (Especially when you have a drummer trying to outdo John Bonham).

Perhaps a 6L6 run at lower voltages. There's no reason you have to push 6L6's to 40 watts or more.

Or perhaps a higher voltage 6v6 amp. Seems like quite a few people here have success running higher voltages on the JJ's.

Or maybe a quad of 6V6.

[Reeltarded]

It's easy to pick a large value resistor in a mixer and then pick one that sends most of the signal to nowhere. You get fat ass but not enough to make the next stage giggle.

KT88 or 6L6 with lowere voltages would definately make a great back side on an amp with tiny-/jumbo + mixers to an LTP with a ton of NFB.

[Morgan]

I've experienced this problem. Basically wanting something between a 6V6 and a 6L6 based amp. The 6L6 doesn't break up at all at band volumes, but the 6V6 breaks up too early. (Especially when you have a drummer trying to outdo John Bonham).

Perhaps a 6L6 run at lower voltages. There's no reason you have to push 6L6's to 40 watts or more.

I've been in this situation too lately; the band expanded to a 5 piece, is playing larger stages, and suddenly the fiddle player we added seems to be gobbling up the same frequencies as my 5E3 that I always use, and I've run clean out of any headroom whatsoever.

I love tweed amps and always wanted to play a 5E7 (3 x 10 combo) so I went ahead and built one. Problem solved! Pre-amp is very slightly scooped compared to a 5E3 and it seems to fit around the fiddle player now, and the power section is just awesome! 2 5881's with a cathodyne PI and a 35 watt OT. It still doesn't quite break up soon enough at some of the smaller venues, so I plan to go to cathode bias + VVR to knock it back a tad.

But that 5881/ smaller OT power section really seems to fit perfectly right in between your typical 6V6 vs. 6L6 PA...

[LeftyStrat]

I've been in this situation too lately; the band expanded to a 5 piece, is playing larger stages, and suddenly the fiddle player we added seems to be gobbling up the same frequencies as my 5E3 that I always use, and I've run clean out of any headroom whatsoever.

I love tweed amps and always wanted to play a 5E7 (3 x 10 combo) so I went ahead and built one. Problem solved! Pre-amp is very slightly scooped compared to a 5E3 and it seems to fit around the fiddle player now, and the power section is just awesome! 2 5881's with a cathodyne PI and a 35 watt OT. It still doesn't quite break up soon enough at some of the smaller venues, so I plan to go to cathode bias + VVR to knock it back a tad.

But that 5881/ smaller OT power section really seems to fit perfectly right in between your typical 6V6 vs. 6L6 PA...

Thanks, this is definitely good to know. I'm off to check out clips of the 5e7...

[xtian]

Thanks, Morgan. I'm still researching. My desk looks like a snowstorm of Fender and other schematics. It's nuts how much info I've absorbed over the past couple of years, yet how much I still don't know. Far more of the latter.

Keep on keepin' on!

[xtian]

What's the diff? Bandmaster 5e7 and Super 5f4? The only diff I can spot is the local feedback resistor around the second preamp tube: 10M on Bandmaster, 4M7 on Super.

[Morgan]

What's the diff? Bandmaster 5e7 and Super 5f4? The only diff I can spot is the local feedback resistor around the second preamp tube: 10M on Bandmaster, 4M7 on Super.

The 5E5 (1x15), 5E7 (3x10), and 5F4 (2x10) circuits are all pretty much the same amps with different speaker configurations and slight tweaks to those FB resistors.

BTW - as a 5E3 nut, I really dig the 5E7/E5/F4 circuit. It's a real good medium between a 5E3 shooting pure midrange like a laser beam into the audience, and the too loud, too scooped (for me) tone of a bassman. It seems to fill a room much better without being so beamy as a deluxe, but not so clean and loud as a bassman.

[Structo]

Interesting comment about NFB.

Couldn't one in theory take a pretty powerful amp that you like the tone of and dial it back with NFB cleaning it up?

[LeftyStrat]

Interesting comment about NFB.

Couldn't one in theory take a pretty powerful amp that you like the tone of and dial it back with NFB cleaning it up?

I've been wanting to experiment with variable NFB using something like an LDR to avoid the scratchy pot. I guess though it would affect the feel of the amp. Without NFB the transition to distortion is more gradual.

[Tone Lover]

Interesting comment about NFB.

Couldn't one in theory take a pretty powerful amp that you like the tone of and dial it back with NFB cleaning it up?

I've been wanting to experiment with variable NFB using something like an LDR to avoid the scratchy pot. I guess though it would affect the feel of the amp. Without NFB the transition to distortion is more gradual.

The thing about the scratchy pot it doesnt come into play much.
usually you dial it in then it never gets touched again.
Or dont mount it, dial in one configuration for single coils and one for humbuckers measure make it two resisters and switch one resister over the top of another to get 2 differant neg. feedbacks .
Bill

[Reeltarded]

All my vintage Marshall stuff scratches and I use the vintage setup in my amps.. The "newer" setup with the 4k7/25kL is worthless to me. I like 100k/4R for dirty, and 27k/16R for clean. Yes, you can contain insanity with the NFB, for sure.

You know what I hate? Here it comes.. hang onto your seats.. tweed bassman amps. What a gnarly buzzing treble cannon. The 4 input models are insane at lead breakup, and the 2 input model is as dull as a spoon. They weren't meant to do what I like though. I like a bandmaster much better. Those work.

One dumbass opinion.

[Phil_S]

...Ampeg circuits? I know Hull (?) hated distortion!

Yes, not sure who, but if you read the Ampeg literature that was enclosed with your new amp, there were instructions (LOL) on how to set it to avoid distortion. Take a look at some of those early Ampeg designs and you will probably come up with something good. Look at the G12 Gemini, strip it down to one channel and omit R&T and you've got a pretty quick project.
http://www.drtube.com/schematics/ampeg/g12-jp.gif
It's got an interesting PI, a paraphase 7199. I don't recall ever hearing one of these, so I'm going on reputation.

[rdjones]

...Ampeg circuits? I know Hull (?) hated distortion!

Yes, not sure who, but if you read the Ampeg literature that was enclosed with your new amp, there were instructions (LOL) on how to set it to avoid distortion. Take a look at some of those early Ampeg designs and you will probably come up with something good. Look at the G12 Gemini, strip it down to one channel and omit R&T and you've got a pretty quick project.
http://www.drtube.com/schematics/ampeg/g12-jp.gif
It's got an interesting PI, a paraphase 7199. I don't recall ever hearing one of these, so I'm going on reputation.

I think the PI is actually a cathodyne (47k/47k) with a "fixed bias" variation using a voltage divider.
Sunn and Univox I believe used a similar, but not identical, arrangement with 7199 or 6AN8.
The Sunn is a direct coupled version.
Definitely more hi-fi oriented than musical instrument.

rd

[Phil_S]

RD: you are right about the PI. That style of drawing may have confused me. I see it now.

The thing about a cathodyne (or concertina) is that it has 0 gain, which is good for making clean tone.