JMF Spectra 120-7 tube amp

[pchilson]

Hi,
Today I found this amp on CL for small money. The condition is very good, a bit dirty as it has set in a basement since the '80s unplayed. 1x12 combo plywood cab. 3 12AX7A/7025 pre, 4 6L6 power. I haven't run across a schematic as yet. Haven't looked inside the chassis yet. Haven't even played it more than a minute yet. Was wondering if anyone here knows these amps and can report on them. Appears to be a 120/60 watt amp, switchable by toggle. 8 ohm speaker out, FX loop, 2 channel, reverb, presence, standby switch, polarity switch. Lead channel and reverb is footswitchable, footswitch included. The power transformer is massive, the speaker has a very large magnet, this thing is heavy. Can't think of anymore now, will add as I do.

Pics

[pchilson]

More pics

[pchilson]

couple more

[pchilson]

The 6L6s that were in the amp have no markings on them other than the "6L6 GC USA" on the glass. The brand label must have been rubbed off and there is no EIA code on the base. Anyone able to recognize these from the pics?
Also the speaker code is for Pyle, don't they make car audio speakers?

[popthree]

wow, i had the 30 watt little brother to that amp... way back.. like 84 or 85.. i bought it brand new. it was a great amp. the cleans were pretty good from what i can remember, and the crunch channel wasn't too bad. had a nice reverb too. i wish i could find one today.. just for nostalgia's sake. i thnk you got a great deal for $100 ! congrats.

[pchilson]

Yeah, I figure the speaker code puts it at around '83 time frame. Cleaned er up, pulled the chassis to have a look see and swapped the speaker for one of my Eminence Red, White and Blues. When I pulled the fuse cap off the fuse was stuck to the inside of the cap and was broke, so that put and end to playing it tonight. Will pickup up some 6A Slo-Blo fuses tomorrow and see how it sounds with the speaker swap.

[HOBBSTER01]

Nice find.
I had one of those back in the day.
Bought it new as a rehearsal amp to keep under the bus for small venues.
Alas it was stolen in Texas during a show at a state fair when someone (oops) forgot to lock the bins down during a show.

[pchilson]

I just came back from getting some new fuses. Amp works a charm.
When I bought the fellow said the reverb didn't work and it didn't but he indicated he had "fixed" it before. I did some testing but couldn't find a fault with it so my deductive mind told me to swap the cables around...duh, anyway the other part of the equation is the footswitch must be used to turn the reverb on and off as there is no switch on the control panel plus there is no led on the footswitch to give you the state of the reverb...Also the footswitch must be used to turn on/off the lead channel for the same reason, no control panel switch.
I have also deduced the 6L6s to be GE as they match several pics I found of GEs.
What other famous amps use 4 6L6s that might have a comparable circuit that I could get a schematic for and see if there are similarities.
Back to playing, this thing has a lovely sound.

[JohnnyAtomic]

these amps are what later became "dean markley" amps

[pchilson]

Yes, I have learned this. There is a Dean Markley Legacy amps page but this amp is not specifically listed with schematic.

I don't know, I guess no one really has anything to say or contribute on these.

[JonnyM]

Good, No EXCELLENT find. I just nearly duplicated your find last month at the Sacramento Antique Fair, a monthly event under the overpass. You rarely find anything good musical, but I keep looking. I did find a way cool pump organ (think Neil doing the acoustic version of Hurricane that folds up into its own box for transport, but I digress. Mine is identical in cosmetics but is a 60-7 Obviously half the power and just two 6l6's. Pretty much the same otherwise, a Pyle 12-inch speaker date 1983 that sounds decent to my ear, at the moment all my spare 12's are either 4-ohm or 16-ohm so I've got nothing else to try that wouldn't cost me something. I paid $150 with some risk as I couldn't test it first, although the vendor is always there, I could have took it back the next month. It works pretty good. It seemed it little flaky at first, but after I took all the tubes out to test them on my Hickock and then put them all back in, it seems maybe on or two were a bit loose at it seem pretty tight and reliable now. The pots can be a bit scratchy but after a few hours of figuring out how the two channels interact without a pedal and it's pretty clear that's something I never find (weird DIN plug) I found my sound, I just adjust the master volume to suit. I can produce nice tone anywhere from just audible to extremely loud. I would put it about equal to a Bandmaster or Pro Reverb in the Fender side. Maybe 45-50 Watts Max, more than I would ever need. The reverb tank is good but not great. It is subtle, you can hear it, it adds some body, it is more adjustable than a Fender with two knobs, but it will never do Surf City. I pretty much set it and forget it. I'm overall very happy with my flea market find, much pure tube bang for the buck and seems pretty robust. It's not the prettiest thing in the world, but I didn't pay for gorgeous, just good tone, and it does deliver. Two Thumbs Up.

[pchilson]

Nice! Now you have to post some pics of it...

[Tim Armstrong]

Extremely cool find!

Tim

[rangercaster]

from a Harmonycentral review ... "Dean Markley has put me in touch with Terry Laul , the builder/designer of these amps so the customer support is great! Terry has been nothing short of amazing with his help and advise."

[Scott S]

That amp looks like a beast!

BTW, you can tell the 6L6GC is a GE by those etched dots under the tube number. I don't think any other companies did that.

- Scott

[wvaslim]

Hello, would you be interested in selling this amp, spectra 120-7?

[pchilson]

The amp has been long sold.