recommendations for a "twin" in a small package ?

[M Fowler]

Some here have built the four 6V6 power section if those guys can comment on that and the tone you are seeking would be very helpful.

[iknowjohnny]

I think it depends more on the design and tranny than having 4 tubes. Look at the peavey classic 30....pretty pure tube path, and i even modded mine further to make it even more so. Still the clean was worthless. Even after putting a beefier heyboer in it. My 18's PA is stupid loud even tho it's 6V6, and very sweet and clean too. So i'm just gonna go with that and a fender pre. I'll surely be asking lots of questions about mating the pre and power in it. The PI is marshallesque as is and it has a cathode follower. So lots of changes in store.

[mlp-mx6]

I don't know anything about the Classic 30 circuit. It being "pure tube" doesn't tell me anything about how the clean tone is designed to sound.

My comment was intended to show that for amps that are "renowned" for a great tone, either clean (Rocket, Twin, and ODS) or distorted in the preamp (ODS), the "girth" of the output section and there being 4 output tubes seems to suggest at least a correlation.

[mlp-mx6]

I just took a quick look at the Peavey Classic 30 schematic and the circuit structure is VERY different from a Fender AB763-style circuit. 2 preamp stages BEFORE the tone stack, "global" negative feedback on the TS recovery amp, and a cathodyne PI. Really hard to compare that circuit with a Fender circuit for clean sound expectations. I certainly would not draw any power tube conclusions regarding clean tones from that circuit design.

Just MHO.

Good luck with your build. I hope you achieve your goals. If so, I look forward to your sharing the resulting circuit with us, it will be very educational!

[FYL]

the "girth" of the output section and there being 4 output tubes seems to suggest at least a correlation.

Two tubes in parallel behave like a big tube with twice the transconductance - more touch sensitivity; app. 1.3 the gain - more mo' more; half the plate R - easier power xfer; twice the Miller capacitance - not a problem in MI amps, can even be a boon.

There can be some problems if the tubes aren't perfectly matched, they would then somewhat "defocus" the sound.

Another important factor is PS stiffness: big bad amps use big bad iron and caps, adding more oooomph even at bedroom levels, kinda cruising at 55 mph in a Ferrari vs. in a Yugo or what's left of it.

[M Fowler]

The more I think about your quest is seems to me that isn't the Brownnote D'Lite what your looking for?

[iknowjohnny]

When i cited the classic 30 the point was that it has 4 tubes and the clean seems to have no headroom and power, while amps with 2 tubes like my 18 (which has 6V6 but DID have 84's at first) has always had far more headroom and clean clear tone like i'm looking for. Even with the heyboer in the c30 it didn't come close. So while 4 tubes may indeed make a difference in this area, i'm just saying a good 2 tuber can be much better tin that regard than a average or mediocre 4 tuber. So I think if i'm not going with a full on twin, and i'm not, i think it will be a crap shoot as to whether a 4 tube PA i build will end up being better in this regard. But it's a moot point because as i said i'm gonna go with the 18 watt and convert it.

Mr fowler....i WILL however take a look at that dlite. I think i may have heard of that b4.

[harryk]

I have mated different preamps with different poweramps with good results without knowing what the results will be. If you want a lightweight Twin, go a Super Reverb way and do it with a pair of 6L6GT tubes. It will give you 40-50 W depending on power suppply etc. You can always use any preamp topology you want (Fender, Marshall, Vox etc.) and only adjust power amp input according that ( Plexi Marshall power amp input cap 22 nF, Fender 1-2.2 nF etc.). Tubes can be treated pretty hard until they die, so make one innovative version and develop it to a final product. Harry

[tubesinside]

1+ for the Super Reverb but with a single 12" Speaker.
I have a Deluxe and a Super reverb and the extra power...stiffer PSU and bigger OPT will give that extra headroom for that clean sound. The Deluxe is brilliant and overdrives the output stage gracefully for that classic blues tone. If I could suggest using a Celestion Alnico Gold as the speaker. Well balanced and loud.

[M Fowler]

Well this is how the Boogie came about the need for small gigging combo with stiffer power section added. Try the Super Reverb with Bassman trannies.

[topbrent]

Big power 4x6L6 in a small princeton reverb sized chassis can be done.
You just need to get more creative with packaging and layout.

A single channel, high power AB763 could be shoe-horned in there with reverb if you want it. Non-reverb would be a much more simple request.

Go solid state rectifier, use the rectifier tube socket for a 6L6, punch out the 4th 12A_7 tube for the larger socket needed for the 6L6. Knock another hole in between v1 and v2 for the bumped 12a_7 tube. Or locate V1 up by the input jacks for very short leads and space savings.

Nibble out the power transformer mounting hole for the el-grande twin size iron. Either eliminate the choke or mount it elsewhere on the chassis.

You will have to have a custom combo cab made to fit this, as there wouldn't be a prayer of this fitting in a stock princeton sized cab and clear the speaker frame. Also, depending on the cab used, you may want to consider a fan to keep the beast cool. That's a lot of glass cookin' in a small space.

[Andy Le Blanc]

toroidal PT, pair KT90, 100w total plate dissipation , same as quad 6l6 biased to 70%.

You could split to two chassis to gain space around the drivers magnet
structure.

Get a 3 in 1 with a box and pan break and get creative.
you don't have to keep making fenders.

[M Fowler]

I get my blank Fender type chassis from pm sound technology he is right now switcing from steel to another material to help with rust but his chassis are blank and allow you to drill away and design your.

I sent an email and will see when he is back up and running as I need another custom 19 inch to go into a gutted Fender Solid State Deluxe combo cab. They make good project cabinets folks.


http://pmsoundtechnology.com/My_Homepag ... Page1.html

Mark

[Bear]

On the quad output theory, Diaz had a quad 6V6 that was supposed to do a lower output Twin vibe. GP reviewed it as sounding good and hitting it's tonal goal. You could maybe get a bit quieter using 6AQ5/6005 or 6K6 output tubes, either of which is 6V6-ish.

[M Fowler]

I got an email back and PM sound technology is back building chassis so I ordered another 19 x 8 x 1.75 slant front chassis.