Marshall 1930 Popular - what should I do with it?

[Reeltarded]

Speak for myself!

[sonicmojo]

It’s not going to be pretty this way but I’m just a few wires away from a mostly stock 18W tremolo circuit and firing it back up.....

[sonicmojo]

Yay, it worked first try!

Here's the before and after pics for taking this Popular from some lead variant without trem back to all the functions working on a mostly correct values 18W trem circuit. I'm still working out kinks and will probably fully redo this board and wiring at some point but I'm pretty happy about how it sounds!

[pompeiisneaks]

Very cool! I like the before/after shots too, quite a difference on that board

~Phil

[Reeltarded]

It looks great! Nice work!

[sonicmojo]

Thanks! Still tweaking. I think I may remove the ugly array of 68K grid stoppers on the side and run coax instead to clean it up a bit more and further reduce hum which is very minimal as is now. I see in the original 18W schematics that the normal channel omitted these resistors anyway. May give that a try on V1 to see how it sounds and if I get any extra RF interference. I'll probably plug the 68K resistors right on the socket at V2.

[sonicmojo]

Still tweaking. I eliminated the extra terminal strips and 68K resistors on V1 and ran coax for the all the inputs to the grids. Dead quiet now. Looks cleaner too I think.

[sonicmojo]

New 1x12 front panel and fresh basket weave. Auditioning some different speakers now. I like my Scumback M75LD pretty good in it right now. A reconed Jensen P12Q didn’t sound right. I’ve heard Celestion Blue is a good option but don’t have one to try. Any other suggestions?




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[Reeltarded]

looks great... I bet a greenback sounds right in it.

[sonicmojo]

looks great... I bet a greenback sounds right in it.

I want to try that and I'm trying to get my hands on one to test out! Funny, but the Vox 10" 7724s (4 Ohm total) that came with this instead of what should be 7442s (8 Ohm total) sound better than anything I have tried yet. The Scumback M75-LD 8 Ohm sounds best yet for a 12" that I have tried but the one I have is rated for 100W and I think it maybe has too much headroom. I think I need to get closer to the 20-25W rating. For this circuit, I am thinking that the right speaker makes a gigantic difference. I think the amp interacts with the speaker more in this case than what I am used to with my bigger amps. Also, whatever PT is in this has super big solid core secondary wires. I am getting 6.7V for the heater windings which is a bit high but I think adds a little bit to what what is happening with this amp to make it sound good so I'm going the extra mile to get the right speaker(s) in it.

[Reeltarded]

Yep.. so the Vox speakers I am unfamiliar with but I am positive that a silver alnico or a real early marked 20w will sound amazing in comparison to just abiut anything.

Even 80s reissues of the 25 that are pre-brutalized make a joyful noise with a low wattage amp.

[sonicmojo]

Well I got a new G12M for it (25W non Heritage). I decided to "pre-brutalize" it myself, heh heh. It sounded quite harsh out of the box but definitely started coming around after about 15 hours on a Variac so I'll probably pound it for a just a few hours more and play it in the rest of the way. I've never done this before with a new speaker or one I have reconed but I can definitely hear the difference!

[Reeltarded]

Yeah it works! I just play through the tightness of a new doping. I haven't used a new speaker in however many years it's been since umm 1989 or something like that. I have faced cabs into a carpeted cement floor and run program through them while I took a trip for a couple days. heh