broken reverb tank in a PEARL amp

Chickenwings

Chickenwings

Alnico 6/8
a friends has a very old pearl sunflower amp (a ss twin copy) and the reverb tank died.
When i took it out i found that the spring is broken.
DSC_0232.jpg
I dont think i can re-attach it, so im thinking of just replacing the tank.
There are no markings on it, and there is very little info on the net about this amp.
Can i just get any accutronics or mod tank and wire it in, or is there something else i need to know?
 
Re: broken reverb tank in a PEARL amp

Whip it out and stick it in. Same size as the last one should work nicely. Oh wait, did I just type that???
 
Re: broken reverb tank in a PEARL amp

Ideally, you would want to know the input impedance and the output impedance to order the correct replacement from Accutronics, or whoever else.

You could also contact Cal Shuett at Accutronics. He was very helpful when I needed to replace my Ampeg's reverb tank. Here is his contact information:

Cal Shuett
Sound Enhancement Products, Inc.
325 Cary Point Drive
Cary IL 60013
U.S.A.
cal@sepigroup.com (or cal@accutronicsreverb.com)
 
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Re: broken reverb tank in a PEARL amp

thats brilliant itsa, thanks.
ill send him an email although id be amazed if he knows the values for this amp - the original tank is not accutronics. the only markings on it are INPUT, OUTPUT and inside it has had Q5 stencilled in.
 
Re: broken reverb tank in a PEARL amp

q5 doesnt show up on the accutronics chart crusty. maybe cos the tank is not accutronics.
 
Re: broken reverb tank in a PEARL amp

gibson175 said:
q5 doesnt show up on the accutronics chart crusty. maybe cos the tank is not accutronics.
Click to expand...

I don't think i explained myself very well. If you measure the resistance of the coils, take note of which way the spring unit is mounted, how many springs, long or short etc. you can create an Accutronics code for the spring you have, and then look at their list of models to find the code that is closest to what you came up with. Then you will know the Accutronics equivalent. The resistance of the coils will be the most important element.
 
Re: broken reverb tank in a PEARL amp

If you work out what the input and out put impedances are, post them.
I've got some tanks Crusty gave to me. Also the tank dimensions would help. If there's one that suits I could send it to you.
 
Re: broken reverb tank in a PEARL amp

GoldenVulture said:
If you work out what the input and out put impedances are, post them.
I've got some tanks Crusty gave to me. Also the tank dimensions would help. If there's one that suits I could send it to you.
Click to expand...

Yup, those all have impedances for s/s applications. The first pic *looks* like a long spring enclosure, so if G175 can take the DC Ohms coils resistance readings, i'd say it's highly likely that one of those will do the job.
 
Re: broken reverb tank in a PEARL amp

q5 doesnt show up on the accutronics chart crusty. maybe cos the tank is not accutronics.
 
Re: broken reverb tank in a PEARL amp

gibson175 said:
q5 doesnt show up on the accutronics chart crusty. maybe cos the tank is not accutronics.
Click to expand...

Ummm ... didn't post #8 help with that ? I know the spring you have is not Accutronics, just trying to help you work out what Accutronics model would be comparable, so you can use that as a reference. Or have i missed something ?
 
Re: broken reverb tank in a PEARL amp

G175. you've got a multi meter haven't you ? Measure the coils in it. With nothing plugged into it take a reading off the two plug terminals. MultiM on the X10 ohm scale.




Edit: .
 
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Re: broken reverb tank in a PEARL amp

crusty philtrum said:
Ummm ... didn't post #8 help with that ? I know the spring you have is not Accutronics, just trying to help you work out what Accutronics model would be comparable, so you can use that as a reference. Or have i missed something ?
Click to expand...

yeh. sorry about that crusty.I dont know why it got sent twice. maybe i pressed the back button or something. i had typed that message this morning but thought did not press send...then i realized this arvo and pressed send i guess after you had made that post.
just ignore the double post
 
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Re: broken reverb tank in a PEARL amp

GoldenVulture said:
G175. you've got a multi meter haven't you ? Measure the coils in it. With nothing plugged into it take a reading off the two plug terminals. MultiM on the X10 ohm scale.
Click to expand...

ive got 1.5 ohms on the input side (that is a reading of 1.5 on the 200ohm selection on my cheap multimeter) if ive got it right. i cant get a reading off the output. seems like a weird kind of reading tho looking at the accutronics ones.
 
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Re: broken reverb tank in a PEARL amp

gibson175 said:
ive got 1.5 ohms on the input. the other gets no reading.
Click to expand...

Hmm. Did you try setting the meter to a higher resistance range to measure the one that appears to have no reading ? Usually there's two things that will stop a reverb tank from working (by which i mean the tank itself, not faulty circuitry) ... either a spring breaks or one of the transducer coils has died. Seeing the broken spring in the pic gave me hope that both the coils might have been intact. Of course it can be possible for a tank to have both problems.

Is the tank long or short ? (i.e. is it about 9" long, or about 17" ?)
 
Re: broken reverb tank in a PEARL amp

gibson175 said:
ive got 4.4 ohms on the input side (that is a reading of 4.4 on the 200ohm selection on my cheap multimeter) if ive got it right. i cant get a reading off the output.
Click to expand...

Hmmm. One coils seems like it's almost shorting and the other is open circuit.
Are the input/output wires soldered/screwed or with plugs ?
It looks like soldered/screwed from your pic.
attachment.php
 
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Re: broken reverb tank in a PEARL amp

It's important to take the readings at the end of the coil wires, where they're soldered to the connectors. Don't try to use the tank chasis as the ground for taking the readings, as many springs have one coil isolated from the tank body to eliminate a potential ground loop.

You may need to set your meter to a range higher than 200 Ohms ... start with a high range and work your way down once you see some kind of reading.

(I've been doing some digging around, there are references to these amps, and pics, but it doesn't look like it's going to be possible to find a schematic unfortunately).
 
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