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Problems with the vibrato/tremolo on my DRRI...

gypsyseven

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Nov 17, 2009
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767
A few days back i noticed that the tremolo/vibrato doesn't work anymore on my DRRI...
Any suggestions to check what's wrong?

Changing the tube?

Should it work also without the footswitch?

Unfortunately i have no amp tech near me....
 

MikeSlub

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Jul 15, 2001
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15,049
I believe blackface amps need a foot switch for the vibrato to work.

If that doesn't help, I could be the tube that drives the vibrato.
 

gypsyseven

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Nov 17, 2009
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767
I believe blackface amps need a foot switch for the vibrato to work.

If that doesn't help, I could be the tube that drives the vibrato.

Yeah, thank's.I already found out that it needs the footswitch....check the tube tonight...thanks, Mike.:dude:
 

cryptozoo

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Jun 25, 2008
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Only a handful of components in that circuit, most of which you can't mess with unless you drop the chassis.

But you can:

- change the V5 and V4 tubes, see if you get Vib.

- make youself a shorting jack with the end of an rca male or 1/4" connector (can't remember which the DRRI uses, but ground the tip and sleeve), plug that in to the footswitch jack, see if you get Vib.
 

gypsyseven

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Nov 17, 2009
Messages
767
Only a handful of components in that circuit, most of which you can't mess with unless you drop the chassis.

But you can:

- change the V5 and V4 tubes, see if you get Vib.

- make youself a shorting jack with the end of an rca male or 1/4" connector (can't remember which the DRRI uses, but ground the tip and sleeve), plug that in to the footswitch jack, see if you get Vib.

Thanks mate,

but i changed all tubes and even tried another footswitch but nothing....:dang :dang :dang
 

Wally

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Feb 27, 2003
Messages
3,454
V5 is the vibrato function tube. A grounded RCA plug as suggested is a definite tool for this application...it will make the ground that the circuit has to see in order to work. There is such a thing as two bad footswitches...unless they work with another amp.
Sometimes, you can take a peek through the Ext Spkr jack with the Vib function engaged and see whether or not the opto-isolator bulb is working...sometimes the shrink wrap is closed off on that end and one cannot ascertain anything by peering through that 1/4" hole. IF the gruonded plug and/or a new V5 doesn't cure the problem, one is going to have some tech time inside the circuit....bad resistor, bad cap, bad connection, or a bad opto-isolator.
 

cryptozoo

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Jun 25, 2008
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And not to assume, but you are plugged into the reverb / vibrato side of the amp, right?
 

gibson-r8

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Jul 15, 2004
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522
Did you try a scientifically placed whack on the side of the cabinet?
 

gibson-r8

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Jul 15, 2004
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Sorry, but i don´t get it:hmm

Sorry, tried and true technique I learned from my father to get the television to tune into the station. When in doubt, give the beast a whack on the side with the flat of your hand!
 

Wally

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Feb 27, 2003
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gibsonr-8's 'whack on the side of the cabinet' is almost always a temporary fix when looking for a solution, but it can be a very good diagnostic clue when looking for a problem.
 

gibson-r8

Active member
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Jul 15, 2004
Messages
522
yea, poor connection, bad solder joint, tube socket, lots a potential connection issues. The discrete whack can point you in a direction. Plus, it is cathartic.
 

gypsyseven

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Nov 17, 2009
Messages
767
Sorry, tried and true technique I learned from my father to get the television to tune into the station. When in doubt, give the beast a whack on the side with the flat of your hand!

Now i got it....sorry, my English´s not the best.....
 
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