GRAAF GM50 Compatability issue

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I have a GRAAF GM50B INTEGRATED AMP. I would like to fit a set of cryod TUNG-SOL KT120 Tubes to the Amp. Can this be done without damaging the amp. The TUNG-SOL KT120 has a rated 60W power output. The filament draws a little more current than the KT88s. Will this extra current take out the GRAAFS power transformer. The GRAAF has 50+50W RMS power output.
 

oldric_naubhoff

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you'd do a better job if you turned with this question directly to the manufacturer. I guess noone around here is capable of giving an informed avise on such a technical issue. that's one thing. the other thing is that power output of the tube amp is a derivative of the tube component used. so if your amp has 2*50W output it means that it's achievable with KT88s. if you used other compatible output tubes you'll get different output power.

BTW, how would you rate your Graaff amp?
 
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Anonymous

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Yep! Already tried manufacturer, gone out of business. Also tried four of GRAAFs distributers (agents) still no luck.

The TUNG-SOL KT120 doesn't look like it'll drop into much. Indeed - look at the heater current requirements. 1.7 to 1.95 amps per tube! That's 6% to 22% above a KT-88. Four of those could end up needing as much as an amp (or slightly higher) more than four KT-88s. How well that plays with anybody's power transformer is to be seen I guess.

(meltdown comes to mind).
 

oldric_naubhoff

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marshmellow29 said:
Yep! Already tried manufacturer, gone out of business.

such a shame! I really respect Graff.

marshmellow29 said:
The TUNG-SOL KT120 doesn't look like it'll drop into much. Indeed - look at the heater current requirements. 1.7 to 1.95 amps per tube! That's 6% to 22% above a KT-88. Four of those could end up needing as much as an amp (or slightly higher) more than four KT-88s. How well that plays with anybody's power transformer is to be seen I guess.

(meltdown comes to mind).

well, I think you could also try contacting Tung Sol for clarification. anyway, it's just my wild guess but I think 4*2 Amps shouldn't be too much for a decent power supply. and tube amps definitely have good power supplies. what would worry me if the output from the tubes would not be too much for the output stage to handle?....
 

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