AN Wonderland/JM 100w layout

[M Fowler]

Great that is nice to have all those sizes available to punch.

Sometimes on a rare occasion I'll use ceramic sockets and they are different size then the Belden sockets.

Mark

[Matt J]

Curious...

Has anyone ever tried to integrate a tremolo circuit into this design? If so, what type of circuit did you use and what did you think about it?

- Matt J.

[small cat]

Edit: nvm

[andyhardy]

Was this the amp that was for sale on Reverb a while back

https://reverb.com/ca/item/13002989-two ... ed-by-john

[Bombacaototal]

I am intrigued with an assumption on this circuit. if one is building this amp without the reverb but keeping the additional “mixer” triode between the tonestack and master, would the lack of signal split before the second triode of the pre-amp cause the amp gain to be higher compared to the original?

Or in other words, is there a lower gain or loss in signal caused by the split of the signal after the volume and before the second pre amp triode? The split signal I am referring to is the half that goes to the pre amp second triode and the other half that goes to the first reverb triode before the “SEND”

[pompeiisneaks]

I am intrigued with an assumption on this circuit. if one is building this amp without the reverb but keeping the additional “mixer” triode between the tonestack and master, would the lack of signal split before the second triode of the pre-amp cause the amp gain to be higher compared to the original?

Or in other words, is there a lower gain or loss in signal caused by the split of the signal after the volume and before the second pre amp triode? The split signal I am referring to is the half that goes to the pre amp second triode and the other half that goes to the first reverb triode before the “SEND”

There is definitely a change in the tonal structure. many builds that remove a specific other channel often retain a mixing resistor to ground to allow some portion of the signal to bleed back the way it would have with the other channel(s). Adding them isn't necessary, but it does increase gain, and modifies the tone a bit I think too, because the amount of signal lost into the other channel is also shaped a bit by the caps in the other circuit that reference it to ground etc.

~Phil

[somax19]

Hi,
I built more wonderland,Jm sign ,SSS etc... type amp. I would like to build now a TR Classic Reverb Sig ,but I dont know the operational of gain structure switch
I think is a 3 way cathode resistor/bypass cap switch...or something else:) I watched the CLRS gutshot but I couldn't figure out.
Does anyone the schem of gain structure switch?
(sorry my bad english)

Thx
Laszlo

[Bombacaototal]

I am intrigued with an assumption on this circuit. if one is building this amp without the reverb but keeping the additional “mixer” triode between the tonestack and master, would the lack of signal split before the second triode of the pre-amp cause the amp gain to be higher compared to the original?

Or in other words, is there a lower gain or loss in signal caused by the split of the signal after the volume and before the second pre amp triode? The split signal I am referring to is the half that goes to the pre amp second triode and the other half that goes to the first reverb triode before the “SEND”

There is definitely a change in the tonal structure. many builds that remove a specific other channel often retain a mixing resistor to ground to allow some portion of the signal to bleed back the way it would have with the other channel(s). Adding them isn't necessary, but it does increase gain, and modifies the tone a bit I think too, because the amount of signal lost into the other channel is also shaped a bit by the caps in the other circuit that reference it to ground etc.

~Phil

Thanks for the feedback Phil. Very insightful as usual.

[mojotom]

I think the gain increase would be marginal in that amp. Not like removing a tube stage for exemple. Off course you will hear a difference but because of the huge voltage divider after the second triode V1B (1M/68k to ground) the preamp output will still be quite small going to the mixer tubes. You will have less “loading” removing the reverb load off course but you can tweak it if you want by lowering the 68k. Won’t be the same but you would not alter the basic sound of the amp that much I would say. I put a 100k pot along with the 68k to ground and going too high in value while boosting the signal make the reverb sound weaker (at least that how it felt). I would so not much of a concern.
That voltage divider, the second triode mixing stage and the ODS style power supply (2k2/22k/2k2) are the three main points that make the JM sound the way it does. At least that’s how I feel it.

I can try on mine removing the reverb tubes.

I remember Guy77 did try that amp with no reverb and no mixing stages and felt he lost what he liked about the amp in the first place.

I would build it with the reverb section, one of the best around and tweakable (basically the same “pre” reverb as the SSS).

[Guy77]

Hi Tom. Nice to see you online.
Yes I did try this circuit with no reverb and no mixing stages , I bypassed the mixing stage (4th 12ax7) and pulled the other 2 reverb tubes.
For me I felt that the clean channel (no reverb) lost the lush tone that I enjoyed so much in this amp.
When I made that mode I also had the mixing resistor set to 120- 130K.
I felt it lost too much volume when using the 68K as many others here have also mentioned.

Cheers!

Guy

[Bombacaototal]

Thanks Guy and Mojo. Basically JM stopped using the reverb of this amp in 2013, and has since been using a studio grade reverb in the loop with SEND/RETURN at ZERO. So I thought, how different would the amp be if you get rid of the entire reverb circuit, but leaving the DRY path mixing tube triode. I guess if you remove the mixing stages too the amp is essentially an ODS (minus overdrive). From the amps I've done I always prefer the mixing tube between the pre-amp and PI, then going straight to power amp from the preamp.

Given the signal loss is after the volume and before the 220K resistor that goes to the second pre-amp triode, maybe reducing the volume pot from 1M to let's say 500K could be another alternative? Is there a way to measure how much signal is bleading to the reverb path? Or am I splitting hairs here? Probably best to build with reverb and then chose which approach to take, but now more curious about what the signal is doing inside the topology

[norburybrook]

@banbaccaototal

At this point what are you trying to achieve? If you're a JM fan or a SRV fan this amp will deliver 'that' sound. The reverb is beautiful , probably the best I've heard on an amp if you get a good tank.


If you just want a clean, simple pedal platform then build a small special or built a Bluesmaster without the OD stage and HRM...job done



Don't overthink these things

just build, experiment, play...…..rinse and repeat until you come back to square 1...….



or go mad...…



M

[Colossal]

If you're a JM fan or a SRV fan this amp will deliver 'that' sound. The reverb is beautiful , probably the best I've heard on an amp

Hi Marcus,

Any comments on how this might amp work for Les Paul players?

Dave

or go mad...…

I've always been mad, I know I've been mad,
Like the most of us, very hard to explain why you're mad,
Even if you're not mad

[norburybrook]

If you're a JM fan or a SRV fan this amp will deliver 'that' sound. The reverb is beautiful , probably the best I've heard on an amp

Hi Marcus,

Any comments on how this might amp work for Les Paul players?

Dave

or go mad...…

I've always been mad, I know I've been mad,
Like the most of us, very hard to explain why you're mad,
Even if you're not mad

We didn't try this with the Les Paul, we only moved onto Les Pauls with the ODS amps for a while.

I'll add that I use the JM amp with my D 'Angelico for 'Jazz' tones so it can be a lovely 'sweet' amp. Hitting it hard and loud with a strat with the NFB off just turns it into another beast.


M

[Colossal]

Hi Marcus,

Any comments on how this might amp work for Les Paul players?

Dave

We didn't try this with the Les Paul, we only moved onto Les Pauls with the ODS amps for a while.

I'll add that I use the JM amp with my D 'Angelico for 'Jazz' tones so it can be a lovely 'sweet' amp. Hitting it hard and loud with a strat with the NFB off just turns it into another beast.

Hi Marcus,

Thanks for your comments, that is helpful. I probably should grab a chassis from Taylor and just build one . Although I must admit that I am not keen on the placement of that Gain knob! I know it is a low gain amp and plenty stable, but that irks me a little. Why put the knob over on the bloody right like that? It's like an afterthought. Oh! We forgot to add a Gain knob...put in over on the right...