neonmagic

Valve amp questions...

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6 minutes ago, mr.me said:

Good Luck, I hope you find the problem but BE CAREFUL  :^

Of course.  I accidentally got a 240 AC shock when I was around 10 years old.  That, and ongoing drummings from my late father mean that I treat electricity with the utmost caution (unplugging AC cord, waiting usually half an hour before doing anything and never pulling apart electronic circuit boards etc.  I know my limits and I stick to them like mud to a windscreen.  :)

OK :

swapped out the power board, no change, neither amp powered up.  

swapped out the AC power cord on the Left channel amp to the new power board - amp did not power up.  

swapped out the power cord that goes from the power outlet to the (new and old) power board to a completely different power outlet for both amps - neither amp powered up.  

Disconnected all the new power lead/AC power cord/Power board and reconnected everything up as it originally was.  

Decided on a whim to try both amps - Left channel still dead, suddenly the Right channel is now powering up (all 3 valves lit up like normal).  Weird.  The only thing I changed was the Right channel amp's AC power cord was plugged into a different socket on the old and original power board.  I'd be hard pressed to believe that a socket on the old and original power board is dead.  I know it's possible, but I'd have to be unlucky lol...I can easily test the Right channel by trying the other free sockets on the power board.  This still doesn't explain why the Right channel failed to start up with the new power board...weird!

So, that logically tells me that the valves in the Right amp are potentially AOK - I will do more repetitive testing for the Right channel amp to see if it is now consistent in powering up tomorrow.  If the Right amp is all good from now on, my next logic testing step will be to swap the 845 valves over between the 2 channels.  If the Left channel then lights up, but not the Right channel, this points to a dead 845 valve.  

note: 4.5 years ago, I had an issue with the Left channel not powering up.  I swapped the 845 valves around like suggested above and it showed that the original 845 valve in the Left channel was dead.  I got another 845 valve from a friend who had a spare and the Left channel amp started working again.  I still have the original 845 valve packed away in a spare room, so may try and find it and swap them over to see what happens.  

Hopefully, the Right channel stays consistent now, and the Left channel is just down to a bad 845 valve.  *fingers crossed*!

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Super Wammer

Might be progress!

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6 minutes ago, Fourlegs said:

Might be progress!

Yes!  But now I will really go to bed.  I am 2 and a bit hours past my normal bed time and very tired!  

PS it'd be so nice to live in the UK - beautiful weather (I hate the Australian heat) and lots of lovely British hifi manufacturers to drool over!  Plus, lots of cool audio/hifi shops to visit.  Australia has far less options sadly, and our local retailers/distributers tend to price rape us...BADLY.  

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Super Wammer

I look forward to you sorting your problem tomorrow when you are not tired. It might just be connection problems in the power cable chain somewhere.

Edited by bandit pilot
Self promotion in 2ch
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Super Wammer

I know this may sound daft but also check you've pulled the right fuse from the draw for testing, as some draws carry 2 fuses, 1 in use + a spare. 

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7 hours ago, Fourlegs said:

I look forward to you sorting your problem tomorrow when you are not tired. It might just be connection problems in the power cable chain somewhere.

What a day...dog tired, have had a night terror during the night, now I have had to get up early cos of a variety of circumstances in the household.  

I can't see it being a power cable chain issue - I've replaced the AC power cord, fuse is good, swapped out the power lead, swapped out the power board, and even tried a new power outlet (with the new power lead, board and AC power cord).  I've eliminated and swapped everything...without success.  

59 minutes ago, Lurch said:

I know this may sound daft but also check you've pulled the right fuse from the draw for testing, as some draws carry 2 fuses, 1 in use + a spare. 

The pull out tray only has 1 fuse.  I can take a photo of it if you want.  My preamp (8000C, Audiolab), has a fuse holder that can carry 2 fuses.  But, not the Cyber 845 units.  Good idea though!

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Super Wammer

My comment was really aimed at making sure you were actually getting power through to the amp end of the cable. 

I would suggest that if you have one amp working then use the cable from that amp and plug it into the other amp without changing anything 

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7 minutes ago, Fourlegs said:

My comment was really aimed at making sure you were actually getting power through to the amp end of the cable. 

I would suggest that if you have one amp working then use the cable from that amp and plug it into the other amp without changing anything 

it's not a bad idea and easy enough to do and can't do any harm to try.  It's 5pm here, have had a full on day, still doing chores around the house before I can even think of sitting down for the evening.  Will post later after I've tried a few things.

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Update:

swapped the AC power cord between the 2 amps - no change.  Left channel does not power up.  

Now, I had adjusted the bias pot all the way counter-clockwise before I'd tried the amps last night, so thinking that perhaps that has something to do with my problems, I adjust it roughly to where it was before.  Left amp still does not power up. 

I then returned the AC power cables to their original amps.  I swapped over the 845 valves.  The Right channel (with the 845 from the Left), powered up AOK.  So, the Left 845 valve is AOK.  The Right 845 (which worked fine in the Right monobloc) did NOT power up in the Left amp.  

This would make me logically think that something has gone bust in the Left amp.  

Question: if the 5687 or E88CC valves were either damaged, or not seated fully properly, would they stop the 845 and amp from working?  Both driver valves feel well seated to me.  

I did mention, earlier on in this thread, that the 845 base in the Left channel felt "loose", so I wonder if it's not somehow set right, which means when the 845 is seated in it, it is not mating electrically correctly.  I am not game to go prodding lol.  

I think I have exhausted all troubleshooting avenues, and done enough logic troubleshooting to point the blame at the amp itself, and not the power outlet, power lead, power board, AC power cord or 845 valves themselves.  

edit: my voltmeter buzzed in buzz test mode when I tested the fuse for continuity (at least, I hope I tested it right).  I will ring Jaycar in the morning (where I purchased the voltmeter from, and clarify that I have tested the fuse correctly).  

2nd edit: I'm going to plug the probe into the Left channel and test it with my voltmeter to see if anything is indeed live.  

Have I missed anything, troubleshooting wise?

Any other suggestions?  

How much would you expect it to cost to have the unit troubleshooted and repaired (presuming it's a bad capacitor or something similar, rather than an OPT)?  Sending the unit back to Opera Consonance in China is out of the question - freight alone is prohibitive.  Then, there's dealing with Australian customs, which is about as pleasant as having your teeth pulled via pliers.  

Edited by neonmagic

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Super Wammer

Valve amps are relatively simple inside and I would expect that there would be someone local to you who could look at it for you without it being expensive. The cost of a repair could be anywhere from hardly anything to quite a lot if a mains transformer has blown. But now is probably the time to find someone to look at it.

Try searching on google for "valve amplifier repairs" local to you. Often these will be guitar amp guys who can also work on hifi amps. An hour of their time to diagnose it should not be too much.

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9 hours ago, Fourlegs said:

Valve amps are relatively simple inside and I would expect that there would be someone local to you who could look at it for you without it being expensive. The cost of a repair could be anywhere from hardly anything to quite a lot if a mains transformer has blown. But now is probably the time to find someone to look at it.

Try searching on google for "valve amplifier repairs" local to you. Often these will be guitar amp guys who can also work on hifi amps. An hour of their time to diagnose it should not be too much.

yeah, I had a quick look tonight.  My suspicion is that things will be cheaper in the UK.  

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