Curtis mathis 190 watt consol conversion.

[kd7ura]

Was wondering if any body could give a bit of advice on this idea.
i have a curtis mathes tube sterio consol in great shape.
its 190 watts 2-12 and 2-8 mid 2-tweets
what would be the best way to do a conversion to guitar amp
i was thinking seperate cabs for the speakers and a third cab for the amp
it has rca plugs on the tube chassie for phono TV and reel to reel.
what would be needed besids whats there to get a good amp going.
new to guitars with a bit of experince on old equipment.
have a few pics of the unit

[kd7ura]

have a list of the tubes inside,12at7-12ax7-6au6-6ub-6al5-6ba6-6be6-6bq5.
im looking for a schematic for it, its a curtis mathes model 930CV The royal dane.
,, ive been reading other postes im already sterting to get giddy!!!

[J M Fahey]

¿190W?

[kd7ura]

Looks like 80 watts per channel been drawing out the shematic for the tape inputs its all deadbug.
looks like tape input into a pair of 12ax7s then another set of 12ax7s then into 4 6BQ5s, not sure exactly.
it has 2 transformers on the main chassis one for each channel, so the path for one channel is 12ax7 to 12ax7 to a pair of 6bq5s

[ThermionicScott]

I'd bet a lot of money that 190 watts refers to the power consumption by the entire amp, not the output. 4 EL84/6BQ5's aren't good for much more than 36 watts output, without getting fancy on the design. You could very easily build two 18-watt-style amps with what you have, since there are two output transformers.

- Scott

[km6xz]

Curtis Mathias was known for direct marketing and exaggerated specs during the second incarnation of the company. They famously quoted power as Chassis Power which was one of the reasons the FTC stepped in and put a halt to any claims of power in hi-fi or brown-goods(big empty but impressive looking consoles were called Brown Goods) except for FTC power ratings. That C-M 190 watts probably translates into 15 watts/cha FTC power rating. But 15 watts with efficient speakers was loud enough to get the cops called on the kids when parents left them at home alone.

There were other power ratings that came out: Peak power Peak Chassis Power, Peak Instantaneous Power, Peak Absolute Potential power, Program, Peak Program, Peak to Peak Program, and several others that were made up by marketing and advertising to confuse consumers with impressive sounding numbers for really crappy cardboard backed consoles and TV combos. The Relationship between FTC power and PIP was 2800% difference. A typical 400 watt PIP console was actually a good solid 12 watts RMS. The key to many of these was peak instantaneous levels, projected to a full second, and peak to peak. In other fields pulse power measurement specify pulse duration, like in radar and the values are quite large compared to averaging over a second. A Million watt radar pulse might have a duty cycle of 0,005 % and have a RMS value of 10 watts. Now, we have the FTC to thank for putting an end to all that ad hype in consumer products. FTC power is pretty conservative and requires a preheating period before the measurement that was chosen to really stress solid state amps AB at the time. Now with so many classes that do not have the same mid power heating issue as AB we have some remarkably efficient amp topographies, that sail through the FTC test routine. With conventional amps it requires a lot of iron to have the reserved needed for the test.