(Dean Markley) Spectra 212-t schematic wanted

[sgelectric]

Does anyone have a schematic for a Spectra 212-t amp?These were later bought and distributed by Dean Markley. Thanks, Steven

[Steve L]

You may find it here:

DMS - Amplifier Documents

A lot of their amps were a combination of common preamp and power amp circuits.

Steve

[sgelectric]

Thanks for your reply.I have found that site but it doesn't have the 212-t. The preamp and power amp circuits are indeed common but I'm actually more interested in the footswitch and switching circuitry. A friend has the amp minus the footswitch so I was hoping to reverse engineer one or a least hack it so that he can use the switchable features on the amp, like the B channel etc............ Again, Thanks, Steven

[crossguy]

I may be able to help. 212t schemo.

Used to be a factory tech. Got docs.
What do you need?
DWC

[sgelectric]

Thanks for your response.I ended up buying a set of barely legible schematics on-line and managed to sort out the amp and footswitch.If you have good copies of their tube amp schematics, I woud appreciate them.The 212-t in particular. Thanks again. Steven

[cppswengr]

Spectra 212-T

Used to be a factory tech. Got docs.
What do you need?
DWC

Hi I recently bought a used 212-T here in Michigan and would like to get a set of documentation for the amplifier. The schematics and manual would be awesome. If you have these please let me know how much you would charge.

Thanks.

[sgelectric]

I hope the footswitch came with your amp.
The amp is actually a "212-T" ,not "7".They just used an unusual font.
Good luck. SG

[cppswengr]

Thanks for the correction on the name, that's pretty funny. I did get the footswitch (whew) as I don't see another way to control some of the amp's feature.

[sgelectric]

Glad you got the footswitch.

There is a variable bias mod that can be implemented on the circuit board.I believe it will be noted on the schematic that Crossguy has.If not, I may be able to find it.

[cppswengr]

Variable bias mod

Crossguy has not responded so if you can find the variable bias mod I'd greatly appreciate it.

Thanks

Glad you got the footswitch.

There is a variable bias mod that can be implemented on the circuit board.I believe it will be noted on the schematic that Crossguy has.If not, I may be able to find it.

[sgelectric]

I sent you a PM...........Let me know what you want to do.

SG

[crossguy]

Sorry for the long delay in reply.
Been too busy and am movin to new digs. I need to rescan the schematic. The f/s jack is the big issue. it was made by AMP and the connectors are impossible to find. the original unit HAD adjustable bias.
email will keep me in touch!

[oshiwei]

Used to be a factory tech. Got docs.
What do you need?
DWC

Can I get a copy of the schematics, as well? I have had a JMF Spectra 212-T since I was 15 and I love it. I have replaced the tubes and had it biased several times. But I was thinking of doing it myself this time. I would love to know more about this amp. Anything you can tell me or provide would be appreciated.

[crossguy]

Wowser!
My last activity on this forum was 2011! It's been a while.
I am not sure where those schematics are right at this moment, and I am suuper busy with the holiday.
I can probably find something for you but it might be after the 25th.
Memory says the bias was set to around -47 volts at the grid. The amps were biased a bit cool for my taste, but it was to extend tube life on the finals.

[Jazz P Bass]

Pretty poor scan but here it is: jmf_Spectra 212T.pdf