I'm a total newbie when it comes to gear with valves so please excuse my lack of knowledge.
I have a Unison Research SR1 which is an "integrated" amplifier where the preamp has a pair of ECC82 and the power amplifier is a MOSFET amplifier. The SR1 has been sitting for somewhere between 10-15 years.
Now, turning it on it never goes out of the preheating stage. I can barely see any glow at all from the valves. If I turn up the volume I do get sound out of the amplifier but it's really really really low.
So my question is, should the ECC82 have a visible glow when functioning normal? And have anyone here an idea for how long a preamp with ECC82 should be in a preheat mode? Lastly, since I do get sound out of the speakers even though it's maybe around one 100th of what's normal, should my first try be to replace the valves?
Thanks!
I have a Unison Research SR1 which is an "integrated" amplifier where the preamp has a pair of ECC82 and the power amplifier is a MOSFET amplifier. The SR1 has been sitting for somewhere between 10-15 years.
Now, turning it on it never goes out of the preheating stage. I can barely see any glow at all from the valves. If I turn up the volume I do get sound out of the amplifier but it's really really really low.
So my question is, should the ECC82 have a visible glow when functioning normal? And have anyone here an idea for how long a preamp with ECC82 should be in a preheat mode? Lastly, since I do get sound out of the speakers even though it's maybe around one 100th of what's normal, should my first try be to replace the valves?
Thanks!
Yes, they glow but it is very subjective as to how you would describe the brightness.
Small valves like these should be up to temperature in 15 to 20 seconds once the correct filament voltage is applied.
One quick test will prove or disprove if there is an issue and that is to just measure the heater voltage between pins 4 and 5. It should be 12.6 volts. I don't know if the SR1 uses DC or AC heater voltage but the result should be the same. If you can't see 12.6 volts AC on your meter then switch your meter to a DC range and recheck.
Small valves like these should be up to temperature in 15 to 20 seconds once the correct filament voltage is applied.
One quick test will prove or disprove if there is an issue and that is to just measure the heater voltage between pins 4 and 5. It should be 12.6 volts. I don't know if the SR1 uses DC or AC heater voltage but the result should be the same. If you can't see 12.6 volts AC on your meter then switch your meter to a DC range and recheck.
Just refresh the page, I edited the post.
The two filaments can be either in parallel (6.3v) or series (12.6v).
The heater volts is 12.6v between pins 4 and 5 or 6.3 volt if the centre tap connection (pin 9) is used. That is to say 6.3v between 4 and pin 9 and 6.3v between pin 5 and pin 9 if wired that way.
The two filaments can be either in parallel (6.3v) or series (12.6v).
The heater volts is 12.6v between pins 4 and 5 or 6.3 volt if the centre tap connection (pin 9) is used. That is to say 6.3v between 4 and pin 9 and 6.3v between pin 5 and pin 9 if wired that way.
First question would be : does the op own a voltmeter
and is he able to work inside high voltage gear ?
and is he able to work inside high voltage gear ?
Second we would want to know - has this amp been working before in op's system.
Depending on the unknown area he is living in it may be possible to recommend a
workshop. Perhaps the amp was moved from a country with 230 V mains to one with
half the voltage without conversion ?
This amplifier does not have a pre-heating feature. Filaments are wired for 12.6V dc.
If the op (his first post here and maybe still under moderation) has some experience
I would advise some other checks after confirmation that filaments are running low.
Depending on the unknown area he is living in it may be possible to recommend a
workshop. Perhaps the amp was moved from a country with 230 V mains to one with
half the voltage without conversion ?
This amplifier does not have a pre-heating feature. Filaments are wired for 12.6V dc.
If the op (his first post here and maybe still under moderation) has some experience
I would advise some other checks after confirmation that filaments are running low.
We'll have to see what he comes back with 🙂
(As to safety, yes you make a good point but also remember that the safety aspects are clearly mentioned in the acceptance rules which all members must have agreed to before registering)
(As to safety, yes you make a good point but also remember that the safety aspects are clearly mentioned in the acceptance rules which all members must have agreed to before registering)