Cascading channels in tweed amp

[jon]

How would one go about cascading the channels on a 5e4a

[ampgeek]

Check out Hoffman's 18W Stout project here:

http://www.el34world.com/projects/image ... tout_8.gif

The switch that puts V1a and V1b in series can also be configured as a relay for remote activation.

Good luck!
Dave O.

[martin manning]

Here's the simplest way I can come up with... Layout included. One wire on the schematic turns into several on the layout. This is untested, of course, so procede at your own risk!

[rock_mumbles]

Will that work with the shared cathode? Since the signals into the two triodes will be out of phase...

I've done a 5E3 into a cathode biased Princeton like amp and used separate cathodes and a 'normal' wired volume control. It ended up either needing NFB like a Princeton or much smaller coupling caps (0.022uf and 0.01uf's).

[martin manning]

Will that work with the shared cathode? Since the signals into the two triodes will be out of phase...

As long as the cathode resistor is bypassed it shouldn't be a problem.

[dvnator]

Here's another switch option. You might need to tweak a bit to get both options sounding how you like.

[IMG:470:432]http://i671.photobucket.com/albums/vv78/dvnator/Amp%20Stuff/5e3cascadeswitch-schem.jpg[/img]

[tubeswell]

Here's a couple of ideas

Simple single/parallel V1 using input jack tip switches (no extra switches required on chassis) - but this won't do cascading stages. I built several amps with this arrangement and I find it very versatile.
[img:369:494]http://farm6.staticflickr.com/5338/8843 ... c7c8_o.png[/img]

More complicated with a DPDT switch required, but does do cascaded, single, or parallel inputs. (I haven't tested this idea yet myself)
[img:770:414]http://farm6.staticflickr.com/5451/8843 ... 677e_o.png[/img]

[Firestorm]

Will that work with the shared cathode? Since the signals into the two triodes will be out of phase...

As long as the cathode resistor is bypassed it shouldn't be a problem.

True enough, but since the signals will be at significantly different magnitudes, you might want to split the cathodes to experiment with different bias points, bypassed/unbypassed, etc.

[martin manning]

I was going for dirt-simple, and preserving as much of the existing circuit as possible. My first thought was that you could just do it like the inputs on a Marshall 2204, but then the KISS took over.

[jon]

I guess I should have elaborated in my original post. I thinking about building a 5e4a tweed super ( I know the original post said 5e3, my f up) where channel one cascades into channel two, but channel two is completely operational as a stand alone low gain input. I am trying to maintain as much of the original circuit as possible. My original thought was a single input jack with relay switching to access the two channels.

[martin manning]

I guess I should have elaborated in my original post. I thinking about building a 5e4a tweed super ( I know the original post said 5e3, my f up) where channel one cascades into channel two, but channel two is completely operational as a stand alone low gain input. I am trying to maintain as much of the original circuit as possible. My original thought was a single input jack with relay switching to access the two channels.

Elaborated!? This is a completely different question!

[Reeltarded]

Move one of each channels 68k inputs to ground. Swap a pair of resistors to split the signal on channel A with one to ground and the other attached at the junction of channel B's 68k input pair. It might be something like 470k/180k up to 50% ratio without squealing wheelies.

Now when you plug into A you get gain, and B is normal. You can use the switching jack to ground A's signal there when in B if you look close.

B is the only gain/volume control now. You might need a master.. (hint hint)

I hope I didn't make sense, again.

[M Fowler]

Just build this SK-Super Delux see schematic.

The last 5e3 I built I went with single input and master volume like what Mission amps does.

[RB]

Pretty cool M Fowler

How does the dual pot with the presence and master on the same shaft work?

Regards
Randy

[M Fowler]

Pretty cool M Fowler

How does the dual pot with the presence and master on the same shaft work?

Regards
Randy

See my email link send me a message and I can send the layout to you.

Mark