Wonderland without reverb?

[Oddvar R]

Is there a way to omit the reverb circuit on the Wonderland amp?

[Bombacaototal]

Is there a way to omit the reverb circuit on the Wonderland amp?

In short, yes, but you are in for a different amp, as you will need to create a way to bleed the equivalent signal that is lost to the reverb path and also to account for the supply loading effect in just one triode versus two (and this makes a big difference) in regards to the mixer tube

[Oddvar R]

Ok, thanks, I'll leave it in then. What kind of rever tank is used?

[Bombacaototal]

Ok, thanks, I'll leave it in then. What kind of rever tank is used?

The original had a 9AB long

[the_jessmo7]

Is there a way to omit the reverb circuit on the Wonderland amp?

In short, yes, but you are in for a different amp, as you will need to create a way to bleed the equivalent signal that is lost to the reverb path and also to account for the supply loading effect in just one triode versus two (and this makes a big difference) in regards to the mixer tube

Hey bombacaototal, could you speak more to the “supply loading effect” and what that means and possible solutions on how to combat it?

[Bombacaototal]

Usually the B+ will feed two triodes. If you have the same B+ in only one, although voltages are the same, it sounds much more gainy and bright and agressive. I don't like it. The only solution I found so far was to use a dummy triode with plate (coupling cap and a resistor to ground) and a cathode to ground to feed the same B+. Makes a lot of difference. If you have an amp just do the experiment removing one B+ so you can hear it yourself

[Guy77]

Usually the B+ will feed two triodes. If you have the same B+ in only one, although voltages are the same, it sounds much more gainy and bright and agressive. I don't like it. The only solution I found so far was to use a dummy triode with plate (coupling cap and a resistor to ground) and a cathode to ground to feed the same B+. Makes a lot of difference. If you have an amp just do the experiment removing one B+ so you can hear it yourself

Hi Bombacaotota. This dummy load you mention is a very good point. I have also noticed that when trying to recreate the sound of the JM/Wonderland preamp in another circuit its never sound the same as when it is in the JM/Wonderland amp. I know that when building an ODS and you don't have a FET input we would install a 150k - 220k resister across the V1 electrolytic cap on the power supply board to re- create the load on the B+.

You seem to be doing it in a different way. So you are placing another plate resistor on the B+ node and then running a 600v cap to it like a regular plate load and then after the cap instead of going to a pot you are placing a 150k - 220k resistor to ground. I believe you don't connect that to any triode since its a dummy triode.

Just wanted to confirm this is how you did it.

Thanks!

Guy

[Bombacaototal]

Hi Guy, well the dummy FET is one thing, it simulates the B+ and signal drop on the tonestack. The B+ issue I mentioned happens in the mixer supply (dry/wet mix tube) if you build the amp without reverb. It's a bit different because of that. I don't know if you can add a resistor to ground there (like a second 100K), but I thought the dummy triode was a more elegant solution

I have the unused second triode connected with a plate a coupling cap and a resistor to ground along with the cathode cap and resistor. The signal pin is not connected. I call it dummy because it is there just for the loading effect. And how you bias the triode impacts on the B+, so the values of the plate and cathodes will make a difference

[the_jessmo7]

I have the unused second triode connected with a plate a coupling cap and a resistor to ground along with the cathode cap and resistor. The signal pin is not connected. I call it dummy because it is there just for the loading effect. And how you bias the triode impacts on the B+, so the values of the plate and cathodes will make a difference

Do you have any pics of this for reference? Thanks for your help and answering questions. Super interested in this.