Project ideas please?

[livo]

I've just had a mate come and play through my little build project, the 2-Stroke from Dave Hunter's Tube Amp book. Very nice tone and generally a good sound. He would like me to build something similar for him but he would like foot switch 2 channel option.

I've been looking at the circuit for the Super Champ (Deluxe) but I'm not sure I want to incorporate the reverb.

I'm asking for suggestions as to either:
a) modify the 2-stroke to add switchable channel for Lead / Rhythm
b) chop the reverb out of the Super Champ, or
c) other nice low watt, switchable 2 channel project amp along similar lines.

For the 2-stroke I did the whole lot myself including making the chassis and cabinet and board. ie not a kit in any way.

[ampgeek]

Welcome Livo! Looks like you are arriving with some great experiences already in hand.

I have a couple of ideas regarding switching lead and rythmn channels but would need to see the Two-stroke schematic that you are using as a basis.

I am working on a JCM800 design with switching to bring in another tube gain stage. Generically based off of the Hoffman 18W Stout with hot switch which can be seen here but configured like the High/Low inputs on the JCM:

http://www.el34world.com/projects/image ... LTAGES.gif

Pretty straight forward stuff so I have to believe it will be a piece of cake with a Two Stroke.

Cheers,
Dave O.

[livo]

I'll get more for you, but the 2-stroke is pretty much a Princeton I think with a couple of mods. Has a Boost / Voice switch to flick from Tweed to Blackface to Plexi switching to a couple of different Caps before preamp 12AX7 1st triode. Back to the second after single tone pot.

5Y3GT tube rectified. Power Tubes can be 1 or 2 6V6, 1 6L6 or 6K6 or a KT66 or an EL34. All of these give different output wattage from 3 up to about 15.

The OT is switched between the 16 ohm and 8 ohm connections to actually give 8 ohm or 4 ohm impedance to the parallel wired speaker jacks. Speakers are meant to be a Jensen C10R and C8Q (both 8 ohm). I've got the 10" Jensen and an 8" WGS because I ended up with a 4 ohm Jensen 8" by mistake. Speakers connected by jacks so you can pull them as required for 8 ohm or 4 ohm parallel and run either single 10" or 8" or both together.

I've used Classic Tone trannies (standard Fender replacement stuff). It sounds great but we need the foot switch channel change.

The book didn't actually give a schematic but it does have a layout of the PTP board and chassis connections. I'll do a scan and post it up tomorrow.

[livo]

Assembly layout

[M Fowler]

Schematic plus layout with added features.

[dorrisant]

Livo, welcome!!

Mark, did you build one?

Tony

[livo]

OK. Thanks.
I can see the changes made here compared to my original build (as per book).
2 input jacks instead of 1.
Presence and Resonance Pots added.
Filter Cap number and sizes changed (from 40, 16, 8uF to 16, 16, 8, 8uF ) / and voltage divider resistor 22k, not 68k. (Why?)
Impedance switch using all 3, not just 2 OT wires. (Good idea. Greater variability on speakers).
SPDT from P8 of LH 6V6 and added resistor. (does this change the bias for that tube?)
Single Speaker Jack. (Why remove the ability to vary in cabinet impedance?)
Voice switch DPDT with added 1M resistors. (Why?)
NFB switch. (What does this do?)

I think that's all of them.

Please forgive my newbie ignorance. Foot switchable lead / rhythm?

[M Fowler]

Mark, did you build one? Tony

Tony no I did not build one but I was on another forum for awhile where the 2 stroke was the main focus of the forum and lots of info was there.

[livo]

So any ideas on footswitch inclusion? or am I missing something here?

[ampmike]

Mark, did you build one? Tony

Tony no I did not build one but I was on another forum for awhile where the 2 stroke was the main focus of the forum and lots of info was there.

Mark, you are not allowed on any other tube amp forum's.We need you here 24/7 I have that Dave Hunter book,It is a great resource!!

[ampgeek]

Do you want to be able to toggle between the cathode bypass capacitors on V1 via a footswitch?
Dave O.

[dreric]

Mark, did you build one? Tony

Tony no I did not build one but I was on another forum for awhile where the 2 stroke was the main focus of the forum and lots of info was there.

You've been seeing another forum?

[M Fowler]

Oh at one time I like many of you out there, yeah you know who you are members of 7-8 other forums.

I stick to TAG mostly but I do like to see what Metro, Hoffman and SteelguitarForum are up to maybe even the Banjo Hangout sometimes.

Well then there's the SSguitar. I used to hangout with Dr Z but they kicked us builders off, took away the other amp section.

Mark

[livo]

Do you want to be able to toggle between the cathode bypass capacitors on V1 via a footswitch?
Dave O.

No, not really.

Well, I'm not really sure what I need to do, which is why I've asked. I'd really like to have 2 distinct channels but I can't seem to find a schematic for a Low Watt, 2 Channel, Tube Amp. It would appear that only larger amps were made with 2 channels.

As I posted earlier, I think the Super Champ is close but I don't really want the Reverb pan, not that it would hurt by being there. It has a foot switchable channel change from Rhythm to Lead (as well as the reverb).

I don't want 2 inputs (eg, Normal / Bright, High / Low) as this involves unplugging and re-plugging. The cathode bypass caps "re-voice" the 2-Stroke from Tweed to BF to Plexi (supposedly) which is not really what I'm after. I'd be happy to remove that anyway after determining which voice is the preferred sound.

I would like 2 channels, ie: Rhythm and Lead, Clean and Drive, or whatever else they have been called, and the ability to switch between them using a foot switch. I'm not even sure what this involves, or if it can be done in any number of ways. Obviously it can be done and some amps have 3 channels. I've been trying to research different amp designs and schematics to see what's involved but I'm not getting there.

Do I have to include another gain stage? I keep coming up with info regarding the use of Relays to perform the channel switching.

Of course the other alternative is just to put an OD or Distortion pedal in front of the input and use it's foot switch, but where's the learning exercise in that?

[M Fowler]

Google AX84 Lead Preamp it has rhythm channel and lead channel with option to at DPDT switch but would be better to use relay and foot switch.