Classic sixty power amplifiers Maintenance
Re: Classic sixty power amplifiers Maintenance
Hola,
If you are doing resistor measurements in the circuit, at least one side must be disconnected from the circuit. Measurements usually are wrong being into the PC board.
No bass sounds to me is a burned woofer, did you swap the speaker cable at the amp?
If you are doing resistor measurements in the circuit, at least one side must be disconnected from the circuit. Measurements usually are wrong being into the PC board.
No bass sounds to me is a burned woofer, did you swap the speaker cable at the amp?
ML CLX BF-210 Stage X Motion 4. CJ 120SE amp ET7V2 pre, Holo May Kte Dac. Mac Pro. Power Cond. BPT Signature+ 3.5, Gaia II Feet. USB Lush^V3. Nordost SPM IC and Spk. Shun Mook, BCanto CD2 CD3. Linn LP-12/Unitrack tonearm/Denon DL103R MC.
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Re: Classic sixty power amplifiers Maintenance
Hi Roberto,
I have already used spared power amp to test my speakers. Everything work in normal.
I know I should remove the resistor to measure, so when I buy the new one and remove the old one to double check again. Thank you
I have already used spared power amp to test my speakers. Everything work in normal.
I know I should remove the resistor to measure, so when I buy the new one and remove the old one to double check again. Thank you
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Re: Classic sixty power amplifiers Maintenance
So much for the idea of high cost. 5% tolerance and $.15/each. I guess that’s good enough for bias resistors.admin wrote: ↑Sun May 15, 2022 5:48 pm I think these would be the substitute: https://www.ebay.com/itm/20X-LOT-VISHAY ... 04f5e53f59
PS- I think posting in jpg instead of pdf for pictures is better.
It’s just stuff. I like mine. I hope you like yours. I probably like yours too.
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Re: Classic sixty power amplifiers Maintenance
For those curious about why an in situ measurement will be wrong, it is because the meter is looking at the component AND the attached circuit in parallel. The Ohmmeter itself is also in parallel with the component.
The ohmmeter’s Z is VERY LARGE, so it’s path looks like it’s open compared to the other two paths. But between the other two, their combined Z is different from their individual Zs. If you clip the resistor, and put the meter on, the rest of the circuit is no longer in parallel and you get the correct reading for the resistor.
The OP, Roberto, and probably 90% know this, so this note is for those who don’t.
The ohmmeter’s Z is VERY LARGE, so it’s path looks like it’s open compared to the other two paths. But between the other two, their combined Z is different from their individual Zs. If you clip the resistor, and put the meter on, the rest of the circuit is no longer in parallel and you get the correct reading for the resistor.
The OP, Roberto, and probably 90% know this, so this note is for those who don’t.
It’s just stuff. I like mine. I hope you like yours. I probably like yours too.
Re: Classic sixty power amplifiers Maintenance
Understood, then you have a bad cap, not a resistor. Usually a coupling cap is the culprit for no bass. We are just guessing about the problem. I hope you will find the culprit soon...stanleyyu1973 wrote: ↑Mon May 16, 2022 3:10 am Hi Roberto,
I have already used spared power amp to test my speakers. Everything work in normal.
I know I should remove the resistor to measure, so when I buy the new one and remove the old one to double check again. Thank you
ML CLX BF-210 Stage X Motion 4. CJ 120SE amp ET7V2 pre, Holo May Kte Dac. Mac Pro. Power Cond. BPT Signature+ 3.5, Gaia II Feet. USB Lush^V3. Nordost SPM IC and Spk. Shun Mook, BCanto CD2 CD3. Linn LP-12/Unitrack tonearm/Denon DL103R MC.
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Re: Classic sixty power amplifiers Maintenance
Thanks AnotherJohnson & Roberto ! May I know how can I check the caps ? I also have a cap meter, can I using same method to check ? (Removed form board first)
Re: Classic sixty power amplifiers Maintenance
You need to remove it from the board and check the capacitance. Replacement caps are so cheap. If you remove it in the first place I would just replace it.
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Home Theater in Member Gallery
Main stereo: ART Amplifier and ET7s2. 2nd stereo: PV-14L and MV-55. Previously Owned: PF2 preamp, Evolution 2000 Amp, PV-12AL preamp, D/A-2b Vacuum-Tube Digital Processor.
Home Theater in Member Gallery
Main stereo: ART Amplifier and ET7s2. 2nd stereo: PV-14L and MV-55. Previously Owned: PF2 preamp, Evolution 2000 Amp, PV-12AL preamp, D/A-2b Vacuum-Tube Digital Processor.
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Re: Classic sixty power amplifiers Maintenance
You initially implied that one whole side was out.
Maybe I missed the post about just losing the bass.
I won’t speculate further but will enjoy your report when it works again.
Would observe that
“ Polypropylene and polystyrene capacitors, chosen to achieve a high degree of temporal accuracy, are specified for both the audio circuits and the regulated plate voltage supplies for the input and inverter stages.”
The Classic 60 wouldn’t seem to me to be a good candidate for recapping. The polypropylene and polystyrene caps usually go quite a bit longer. But, YMMV.
Maybe I missed the post about just losing the bass.
I won’t speculate further but will enjoy your report when it works again.
Would observe that
“ Polypropylene and polystyrene capacitors, chosen to achieve a high degree of temporal accuracy, are specified for both the audio circuits and the regulated plate voltage supplies for the input and inverter stages.”
The Classic 60 wouldn’t seem to me to be a good candidate for recapping. The polypropylene and polystyrene caps usually go quite a bit longer. But, YMMV.
It’s just stuff. I like mine. I hope you like yours. I probably like yours too.
Re: Classic sixty power amplifiers Maintenance
I don't know your meter, the best way is just disconnect one side of the cap and measure it, taking in care the polarity.stanleyyu1973 wrote: ↑Mon May 16, 2022 5:03 pm Thanks AnotherJohnson & Roberto ! May I know how can I check the caps ? I also have a cap meter, can I using same method to check ? (Removed form board first)
Lacking bass is usually a bad cap, other possibilities might be. You should ask the service dept. (service@conradjohnson.com) They will tell you more what to do.
ML CLX BF-210 Stage X Motion 4. CJ 120SE amp ET7V2 pre, Holo May Kte Dac. Mac Pro. Power Cond. BPT Signature+ 3.5, Gaia II Feet. USB Lush^V3. Nordost SPM IC and Spk. Shun Mook, BCanto CD2 CD3. Linn LP-12/Unitrack tonearm/Denon DL103R MC.
Re: Classic sixty power amplifiers Maintenance
Stanley wrote:..The left channel also have a little bit sound but only have Treble no bass...this implies too that a bad signal tube might be bad too. Change the tube position. The first tube is for left and right channel, then just swap the position. Put it first at the right channel and have a listening. When the right channel goes bad, you can tell is a small tube.
ML CLX BF-210 Stage X Motion 4. CJ 120SE amp ET7V2 pre, Holo May Kte Dac. Mac Pro. Power Cond. BPT Signature+ 3.5, Gaia II Feet. USB Lush^V3. Nordost SPM IC and Spk. Shun Mook, BCanto CD2 CD3. Linn LP-12/Unitrack tonearm/Denon DL103R MC.
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Re: Classic sixty power amplifiers Maintenance
Thanks all kindly advise! My amp left channel have a little bit sound have treble no bass and the right channel work a normal. Previously, I only change all power tubes only. But I didn’t change the small. I think try to replace all small tubes first and seeing what happen ! Thanks Roberto & all again
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Re: Classic sixty power amplifiers Maintenance
Good idea.stanleyyu1973 wrote: ↑Tue May 17, 2022 3:18 am
Previously, I only change all power tubes only. But I didn’t change the small. I think try to replace all small tubes first and seeing what happen.
It’s just stuff. I like mine. I hope you like yours. I probably like yours too.