Tube Radio
Super Member
How warm should a Carver TFM-15 amp run with no signal being fed to the amp?
Carver TFM 15 question
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Rex Aeterna
Gigolo of Gigolos
i don't know. i know it is a conventional class a/b design i believe so it might run bit warm naturally at idle. can always check the bias and reference the service manual to double check. i have a tfm-24 and it runs pretty decent temperature wise but, nothing at an abnormal alert like any other class a/b design. the tfm series are really great amps i think. i just say check the manual and then check the current bias and see how it fairs....
Kingshead
Professor
Owned two of these amps, one bridged mono to run a center channel in an all Carver surround system, and the other driving the rear channels. Never thought they ran more than moderately warm, but then I never really taxed them either with so much over kill power on tap. I really liked these amps, alas they went with the Macs in the great sell off of 2012.
The system had two other power amps, one a TFM 25 driving the mains and the one odd ball of the group, a SoundTech A1000 driving two passive built in subs. When the kids asked me to crank Ghostbusters by Ray Parker Jr it rattled my neighbor's windows.
The amp driving the subs, huge cooling fins so no noisy fans required.
Martin
The system had two other power amps, one a TFM 25 driving the mains and the one odd ball of the group, a SoundTech A1000 driving two passive built in subs. When the kids asked me to crank Ghostbusters by Ray Parker Jr it rattled my neighbor's windows.
The amp driving the subs, huge cooling fins so no noisy fans required.
Martin
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Tube Radio
Super Member
I've got a TFM 25 and a TFM 35 both run cool at idle, but they are slightly different than the TFM 15. I do need to check idle current again as it's been at least 2-3 years since I recapped it and did the idle current adjust.
Thinking about it I think the amp has always ran slightly warm at idle.
Thinking about it I think the amp has always ran slightly warm at idle.
Rex Aeterna
Gigolo of Gigolos
i think tfm 15 to the 35 was traditional designs. have to look and read up again. can be wrong. i think the 45 and up were the designs with the triac at the power supply for lower power draw...my tfm-24 runs cool but, not as cool as my pm600 which is a triac class h design. my tfm seem always run bout luke warm at idle but, i find it normal and of course the other reason can just be cause having my nad 1000s pre stacked on top only leaving bout inch and half of space doesn't help much either but, i never run the amp hard though.
Tube Radio
Super Member
As I recall you are correct about which amps were the traditional design.
The main differences between the TFM 15 and 25/35 amps are the power transformer, and the general layout of the internals.
The 15 uses a toroidal transformer whereas the other two use conventional transformers.
Now if idle current is where it should be then I will consider the amp getting warm to be normal. I should also put my scope on the output to ensure there's no ultrasonic oscillations which if present cannot be heard, but would cause things to heat up given the signal is being fed to the speakers.
EDIT:
Just looked at the service manual and it said to take the idle current measurement when the amp is relatively cool so that tells me the amp does warm up a little after it has been on awhile.
The main differences between the TFM 15 and 25/35 amps are the power transformer, and the general layout of the internals.
The 15 uses a toroidal transformer whereas the other two use conventional transformers.
Now if idle current is where it should be then I will consider the amp getting warm to be normal. I should also put my scope on the output to ensure there's no ultrasonic oscillations which if present cannot be heard, but would cause things to heat up given the signal is being fed to the speakers.
EDIT:
Just looked at the service manual and it said to take the idle current measurement when the amp is relatively cool so that tells me the amp does warm up a little after it has been on awhile.
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