JM/Wonderland/Fairfield County Master Volume

[the_jessmo7]

Hey guys! For those of you who own one of these amps, could you attest to how well the master volume works? Does the amp sound dull at say, 9 o clock on the master volume? How loud is that? I’m wanting to do a JM style build and have had a few who have advised against my original plan to build a full (reverb included) JM preamp. I won’t ever have a need for 100 watts, or even 50. My sweet spot is 22 watts and below. I’m just worried 100 watts turned down won’t sound as good as a lower wattage power section. If I don’t get to hear the beautiful 100 watts that some say I would miss, then what’s the best alternative?

[jazzbass]

Hi the_jessmo7,

I have built some JM / Wonderland and I can assure you that it is not an amplifier that sounds as loud as a 100watt amplifier with another scheme could. A Trainwreck that for the use of four EL84s should express a power of about 35watt is much, much more "noisy" than a 100watt JM / Wonderland even if the volume potentiometer is at 10 o'clock.
It is the type of project that influences the final volume so much that after building the first with two 6L6s I decided that the following ones would only be 100watt.

Franco

[timrobertson100]

Just for an alternative experience… I built my SSS #2 using 2x6L6 and Vibrolux iron for around 35W. It sounds fabulous, even at very low volume, but it can also go very(!) loud. At home it sits around 1/10 on volume into a greenback. I’ll soon build two Wonderlands, and decided for DR iron, tube rectifier, 1x12 combo and 6v6 - just have no need for the extra volume, weight etc. The second is for a friend, and 22W is plenty for his band.

[jazzbass]

Just for an alternative experience… I built my SSS #2 using 2x6L6 and Vibrolux iron for around 35W. It sounds fabulous, even at very low volume, but it can also go very(!) loud. At home it sits around 1/10 on volume into a greenback. I’ll soon build two Wonderlands, and decided for DR iron, tube rectifier, 1x12 combo and 6v6 - just have no need for the extra volume, weight etc. The second is for a friend, and 22W is plenty for his band.

Hi timrobertson,

I'm very curious to have more details about your version of the SSS # 2.
From my experience I can say that the JM / Wonderland 50Watt project has enough power for any live performance but 100Watt is another beast. It is likely that it is a feature of the project but the 100watt has a sound in general more authoritative and convincing than the 50Watt.
Does your version of SSS # 2 use the original circuit?

Ciao, Franco

[timrobertson100]

Does your version of SSS # 2 use the original circuit?

Yes, it’s built from the Ryan/Erwin collaboration on the PCB. Build thread https://ampgarage.com/forum/viewtopic.php?t=34149

It’s the only one I’ve built, so I can’t comment if it lacks complexity in tones that a 100W would provide.

[rccolgan]

It's definitely a quiet amp that has the potential to be a loud beast. My friends describe it as a "bedroom" amp if that helps (even at 100W)

[dbharris]

It's definitely a quiet amp that has the potential to be a loud beast. My friends describe it as a "bedroom" amp if that helps (even at 100W)

Wholeheartedly agree with this! Can dial in the beast to sound great at talking volume, stage, or anywhere in between.

-Dan

[the_jessmo7]

What would I have to change in the circuitry to only use 2 of the 6L6 tubes and build it as a 50 watt amp?

[pompeiisneaks]

Change the output transformer, and remove the two sockets and the associated components for them. You likely also need to adjust the bias voltage as that's designed for a quad of tubes, and the current they'd draw. You can look at a comparable 6L6 based 50W dumble to see what is expected there, but your PT may have differing bias voltages than what's expected... You could also swap PT's because you can use a slightly less powerful one, with less needed heater and B+ current, and then your bias would be more appropriate as well.

Edit: Fixed wording to say differing 'BIAS' voltages.

~Phil