Einstein Combo help!!! -solved-

  • Thread starter Thread starter badgergman
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badgergman

badgergman

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Hello all.

Have an issue with Einstein. Played a gig last night. First set absolutely fine. Back on for 2nd set and I had a severe loss of clean dynamic, nasty midrange (pos 1 channnel 1) growl on clean sound no matter where I set gain. Odd midrange feedback on gain sounds. Loss of bite on these channels too.

Got through the gig but turned on this morning and the amp is producing a loud buzz even without a guitar cord connected to the input jack? This I suspect is not good?

I am assuming pre-amp tube but would appreciate advice. I have a full set of both power and preamp tubes as spare (Diezel reccomended set).

Any help or thoughts most welcome.

Thanks in advance.
 
Whats a hum trimmer?

What tubes power or pre amp?

Any suggestions as to which tubes to replace if preamp?

Thanks Peter.

I have gigs next weekend!!! Starting to panic a bit.
 
Okay.

Just swapped out all pre-amp tubes. Has had no effect. Exactly same symptoms.

Swapped power tubes for a brand new pair. No effect. Same symptoms.

The buzz is at the same volume no matter where the master volume is set and is the same level across all channels and modes.

I plugged a guitar in to see what effect was being had on sound, despite amp being unusable in this state, and though guitar is audible its a seriously fuzzy tone. Horrible really.

I need some assistance here please. How can I get my amp assessed/fixed?

Based in UK. West Yorkshire.

Serial number 004/313.

Please help. I have a gigs booked all year........ Every week.
 
Hi Graham,

I would definitely replace the hum trimmer inside your amp. Any amp tech can do this. Peter Diezel can send you a spare trimmer or if you need to get this fixed really fast you can solder in 2 resistors instead (47 Ohm on left side, 100 Ohm on right side, both 2 Watts). The resistors can be found at any local electronic shop. The resistors are more sturdy than the hum trimmer.

Good luck,

Jens
 
Hey Jens.

Thanks for the response.

I have just taken the amp out of the shell, to see if there was some obvious damage.

I have found a loose wire!! Coming from the far top right of the circuit board, looking in from control panel side marked GNDO and looks like it was connected to the 16ohm speaker jack/rail. I can send you a picture if you wish.

Could this be the cause? The buzz has a definite ground (or lack of) quality about it?

It obviously isn't correct. Shall I resolder it to where it seems to have detached from?

Regards
 
Okay. No more stupid impulsive ideas like that then.

Blew mains fuse in IEC power input jack. Wire looks crinkly now. Uh oh. Not happy.

Obviously not correct place....... But surely this wire being loose is not correct?



Replaced fuse, back to where I started now. At least amp not dead.......

Peter can you send me Hum trimmer and I will see if I can find tech to assist putting it in?

Or is loose wire at fault and I have just put in wrong place?
 

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Another pic so you can exact location of loose wire.

 

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Please solder the loose wire to the ground of the
speaker outputs (the silver wire going through all jacks
and closest to the chassis).

Btw, what´s the signature on the rear plate ? :gethim:

Email resent.

Cheers,
Peter
 
Signature on rear plate and both circuit boards is Sawa. Uh oh....

I must add that the amp was previously working 150% exceptionally.

I can solder pretty well. Let me know if I can "self fix".

Regards
 
Hey Peter, our messages crossed there I think?

I did resolder it there and it blew the mains fuse and the wire has suffered damage? looks like it became hot?
 
Just had a call from my tech and he says he has fixed the problem. Seems it was the loose earth wire after all. He reconnected and says all fine. Thought a power tube socket was a bit loose so re-soldered that but that was more maintenence....

I am really confused as to why when I re-soldered it the mains fuse blew..

Peter, thanks for your assistance and offers of repair. I am happy that I haven't had to courier the amp to Germany for you to just re-solder 1 wire!!! :doh:

Will keep an eye on this one but I am so happy I don't have to go borrowing amps for this weekends gigs.

How did the "discussion" with Sawa go?

Regards
 
I don´t will tell her what happened because she starts
to cry. She´s sensitive when it comes to quality and
is our best member in this case. I cannot imagine that
she didn´t solder the wire in the right way.

Anyway ... sorry for the issue,
Peter :scared:
 
Hey Peter.

I don't want to make anyone upset. The workmanship inside the amp is stunning. Sawa!!! :rock:

As we all know stuff happens to gear, could have been weakened in transit ages ago or could have taken a knock during any of the 50 or so shows I have done with the amp this year.

I tested the amp last night at home, nearly made my wife cry, she was in another room watching TV, or trying to!!

My amp tech biased the amp according to the note on the chassis to 65mA. I had it previously at 70mA. Seems to have made it open up tonally, beautiful sound across all 4 modes. Well, it was superb before... Maybe I want to hear it as better?

Have a concert tonight in a good sized room so will get to hear it at full throttle.

Once again thank you for your offers of assistance, and indeed help via email. I will report back after tonights gig and you can consider this thread solved.


:D
 
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