Einstein reverb problem -solved-

  • Thread starter Thread starter ska
  • Start date Start date
S

ska

New member
Hi, I came back from vacation today and the reverb on my Einstein combo
is not working anymore (it worked fine when I left). Is there any way to simply investigte the problem? The led on the footswitch is turned on, but I don't hear the reverb. When I unplugged the footswitch, I don't hear anything either when I turn the reverb knob on. This is for both channels...
Any help appreciated! Thanks!
 
Allright, I talked to a friend and he thinks the tube driving the reverg is defaulting. Does anyone knows how to check that? I have the combo and have absolutely no knowledge of electronic, learning more about amps is on my to do list... :study:
Any help appreciated :roll:
 
Have a look at the back of your combo. You should see the two big tubes - these are the powertubes. The preamptubes are hidden under metal cylinders. Closest to your input jack is V1. The reverb tube is V7 - on the opposite site.

here's the layout:
preamp-tube layout Einstein



V1  Used by both channels



V2  Used by channel 2



V3  Used by both channels



V4  Mixer & Loop Driver



V5  Return Driver



V6  Phase Inverter



V7 (just combo) Reverb (12AT7)
 
Ok, I had a look, and the tube looks fine... any idea what the pb might be?
:(
 
sometimes the tube may look ok but still be no good. if you have a spare try it. Also can try to remove the tube and replace it in the socket. Also can try to unplu the reverb sends and returns.
 
I have a question on the reverb of my combo also. I seems to be working OK.
Good Luck with yours SKA.

Olaf, hopefully you can provide some assistance. I have a 12ax7a-c pre-amp tube in my V7 socket. I notice that when I turn the reverb up I loose the " openess" sound of the amp. It gets overly compressed to my ears. It definitely changes the tone of the amp. I see you recommend a 12at7 for the slot. Is the 12ax7a-c causing to much gain in the reverb circuit? I hope changing to a 12at7 will correct it. I purchased the combo for the reverb circuit. Thanks for any insight guys..
 
What if the reverb is set to 0? Still compression? Since its definitely parallel, can't be normally.

Yeah, try a ECC81, 12AT7 or 5751 instead.

Good luck,

Olaf
 
Olaf,
Thanks for the quick reply. When the reverb control is set at zero it's fine. As I increase the dial the reverb gets more intense but the tone is also altered.

I'll try to get a 12AT7 today and I'll post the results...Thanks Again.
 
Well....Thought I had a 12AX7 in V7 slot. I must have left the original 12AT7 in and just relpaced V1-V6 with new 12AX7's a while back...my memory is shot :?

I replaced the original 12AT7 with a new one anyway and the sound remains the same.

I have to assume that the tone difference I hear when applying reverb is part of the design. Seems odd though since I have never experienced it before on other amps I have owned.

Would love to hear from other Combo owners from the board if they experience a tone change from the reverb !

Peter, any feedback would be greatly appreciated also :D
 
I tooled around with the amp this evening and came upon another discovery.

The tone changes I have been experiencing only occur when using the amp in a heavy overdriven situuation...which I play in mostly :wink:

On ch-1 mode 1 I don't hear any difference. Once I place the gain above 12:00 on any of the other modes or on the Lead channel is when it's most prominent when I increase the reverb.
 
Allright, I left my amp to a local technician who should take a look at it this week. The guy at the store thought it smellt a little burnt inside the amp... I'll keep you posted. The problem is that I can't annoy my neighbours anymore... :cry:
 
Good luck. Diezels do smell, thats the transformer oil, which might be uncommon even for some techs. Fingers crossed for ya.
 
>|<>QBB<
ska":459a8 said:
Allright, I left my amp to a local technician who should take a look at it this week. The guy at the store thought it smellt a little burnt inside the amp... I'll keep you posted. The problem is that I can't annoy my neighbours anymore... :cry:
Click to expand...

It would be good to have the amp on the workbench.

Peter
 
You might see the amp soon Peter, the tech called today and the tube looks fine. I will ship the amp to the dealer on Friday (I have warranty of course) and he should receive it on Tuesday. Probably he will send it back to you if he can't fix the problem ...
 
what was the problem?

I have the same problem with my Einstein Combo. It is a kind of distorted when i turn on the reverb-knob. Especially in clean mode, but also in channel 2.

4 months before, i changed EL34 tubes and turned bias to 60mA.
After having trouble with irregular collapsing volume before 2 weeks in all channels i changed all preamp tubes. So now all is fine except the Reverb with this distortion. I didn´t realized this before ... hm.

new preamp tubes are:
V1: TAD RT080 7025 WA
V2-V6: TAD RT001 ECC83; 12AX7A-C
V7: TAD RT002 12AT7/ECC81

I also tried an other 12AT7 in V7 but there was no improvement. Any ideas? Thank you!
 
Welcome to the board, Uli :thumbsup:

Where are You located ?

Peter
 
today i could find out when it starts with distortion. Turned on amp in Channel 1 Mode 1 = Clean. Add some reverb - all fine, no problems, sounds good...
Switch to Channel 1 Mode 2. Ok. Turn back to Channel 1 Mode 1. Arghhh. Distortion when reverb is added. And its getting worse the longer i play.
Perhaps a problem with a relay? I think i can´t fix it on myself :confused:
 
You must log in or register to reply here.
Back
Top