20 lb Marshall (or Bassman) Inspired Amp

printer2 · #1 10-29-2017, 02:58 PM

Not 100% sure which way to go but I am building this as a keeper, using the lightest weight cabinet I have. Same can be said about the chassis, the two things that are normal weight are the speaker and the output transformer. No power transformer, I am using a 12V laptop brick for the heaters and to feed the step up high voltage module. I might spring for some reverb (sorry I just had to say it) and that might add another pound. Most of the bits and pieces.

First I have to finish a Ukulele and maybe a guitar that has been sitting around too long. So not much may happen with this in the immediate future (that is if I acted responsibly) but I have been known to go with my heart at times.

MiG50 · #2 10-29-2017, 05:45 PM

So... you're building a Sovtek Mig 50?

printer2 · #3 10-30-2017, 06:58 PM

Do they have a switching power supply?

Steve DeRosa · #4 10-30-2017, 07:06 PM

You had me as soon as I saw those NOS tubes - sweet...

printer2 · #5 10-30-2017, 09:53 PM

Quote:

Originally Posted by Steve DeRosa

You had me as soon as I saw those NOS tubes - sweet...

The nice thing about these tubes is everybody needs 6V6's for their guitar and hifi amps and there is very little call for 12V6's other than car radios where they were intended to live out their lives. So where NOS 6V6's cost an arm and a leg these can be had under $10. I picked up about 20 gently used ones for about $5 each and have a handful of NOS.

printer2 · #6 04-09-2020, 09:04 PM

So long on the back burner, I have so many other projects that are ahead of this one. Not that I need a loud amp anyway. But a complete 180 from a 20 lb amp, how about a home rig with for 12"s?

I still need to stick some grill cloth in front of the panels before I can finish this thing. And any store that I can get something resembling grill cloth is closed because of the darn virus.

The cabinet is from a late 50's hifi radio/record player that had a push-pull 6V6 amp in it. I pulled the guts out of it and the cabinet was mostly sealed and sturdy made that I thought I would keep it and might make a subwoofer out of it. The hifi came with three full range 12" speakers, two front firing one back. I thought I would put a 15" speaker in it but I managed to snag another free Yamaha organ witch happened to have the same speaker as the other three I had.

So really it was a no-brainer that this would become a 4x12. I used one of these speakers for guitar once, they sound pretty darn good. One bright cookie mentioned they looked like a 7/8 copy of a certain JBL, might actually be the case, these are professional grade, I think Yamaha actually used a pair in a SS amp they made. I think I measured one to be in the 100 dB range for one watt. Once I get it buttoned up I will have to figure out what to drive it with. I have a 68 Bassman but it needs a cap job. I do have a 220W per side Yamaha amp, if I put together a tube preamp for it I should be able to get the neighbor's attention on a Sunday morning.