I have a DSL401 combo with a 2 spring reverb tank that's not working.
I connected a Boss VF1 FX processor to the reverb I/O and that works OK, although the signal is a little weak.
The Accutronics 4BB3C1D tank measures 220ohms on the output and 27 ohms on the input. The cables check out OK. I can hear a faint boom when I flick a spring, but nothing like a working one.
Anybody have any suggestions?
Marshall Reverb Tank problems
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lonewolf
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Marshall Reverb Tank problems
Last edited by lonewolf on Sunday Mar 12, 2006, edited 1 time in total.
...Oh, the freedom of the day that yielded to no rule or time...
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lonewolf
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For those interested, here is an Accutronics part code chart for their spring reverbs. Apparently, this tank is F-worded:
http://www.ampwares.com/reverb_codes.html
http://www.ampwares.com/reverb_codes.html
...Oh, the freedom of the day that yielded to no rule or time...
Spring verb tanks are so simple that they rarely go bad unless they're really abused. They're just magnets, coils and springs, and you verified that the coils are OK.
Using a line level in/out isn't a valid test because the signal levels are so different. A line level into the reverb input should have been very hot.
The low impedence input coil is driven by a stage of the amp, and it excites the spring(s). The output coil picking up the spring vibrations is then amplified and muxed into the signal path. One of the post spring amplifier stages or the mux stage could be hosed.
Are you sure that your in/outs aren't backwards? that would cause a huge drop. ~10x the impedance on the input side, and ~1/10 the number of windings picking up the vibration of the spring(s).
Using a line level in/out isn't a valid test because the signal levels are so different. A line level into the reverb input should have been very hot.
The low impedence input coil is driven by a stage of the amp, and it excites the spring(s). The output coil picking up the spring vibrations is then amplified and muxed into the signal path. One of the post spring amplifier stages or the mux stage could be hosed.
Are you sure that your in/outs aren't backwards? that would cause a huge drop. ~10x the impedance on the input side, and ~1/10 the number of windings picking up the vibration of the spring(s).
... and then the wheel fell off.
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lonewolf
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Ron, the measurements on the reverb tank are correct as stated.
I thought the same thing as you, so I had triple checked them. Just to make sure it was reading right, I measured a 2.2kohm resistor and got 2196 ohms.
Unfortunately, the Accutronics spec is in impedance, not resistance. The resistance component on the output could very well be 1/10 the overall impedance.
I had the same problem with a Boogie Mark IV. I tested the reverb send into the VF1 and it had the same level as on this Marshall--about -10db.
On the Boogie, the previous owner bought the wrong version of the reverb tank with a non-grounded input. All I had to do was ground the input sleeve to the tank chassis and it worked OK.
Do you believe the problem is with the tank's output or the reverb return circuit?
I thought the same thing as you, so I had triple checked them. Just to make sure it was reading right, I measured a 2.2kohm resistor and got 2196 ohms.
Unfortunately, the Accutronics spec is in impedance, not resistance. The resistance component on the output could very well be 1/10 the overall impedance.
I had the same problem with a Boogie Mark IV. I tested the reverb send into the VF1 and it had the same level as on this Marshall--about -10db.
On the Boogie, the previous owner bought the wrong version of the reverb tank with a non-grounded input. All I had to do was ground the input sleeve to the tank chassis and it worked OK.
Do you believe the problem is with the tank's output or the reverb return circuit?
...Oh, the freedom of the day that yielded to no rule or time...