Pioneer Reverb-Reverb Tank Replacement

craigmorris74 · 30th July 2005

I recently aquired a Pioneer SR-101 spring reverb. The reverb tanks on the unit are in bad shape, and I am looking to replace them. I am looking at Accutronics tanks:
http://www.accutronicsreverb.com/prodspec.htm
Type 8 fits the description of what I need. However, I have no idea what input impedence, output impedence, and what connectors (see bottom of the Accutronics page) are needed for this unit.
A schematic for the SR-101 can be found here:
http://www.angelfire.com/ky3/craigor...chematics.html
Thanks in advance to anyone who can help.

Craig

brianroth · 30th July 2005

Measure the DC resistance of the input and output coils in the defective tank, then find an Accutronics that matches it as closely as possible.

As far as the I/O connectors, I assume there are RCA sockets on the broken tank. The next questions are whether or not the "shell" of the RCA socket is grounded to the chassis or are floating.

I just went through that same exercise on a Roland "Chorus Echo" box.

Bri

craigmorris74 · 30th July 2005

Bri,
Thanks for your help. I'll measure and see what I get.
Craig

dharma one · 31st July 2005

ive been trying to do something similar but vice versa- using accutronics driver schematics with a hammond spring tank.

i initially thought the dc resistance would be quite close to the impedance at 1khz but looking at this chart

they appear to be quite far off. theres a way of measuring the impedance with a test tone, multimeter and 50k pot but i cant remember it off hand..google should find it

brianroth · 1st August 2005

The DC resistance should still be a useful "single point" for comparison. DCR and impedance at 1 kHz will be VERY different. However, Hammond, Accutronics, etc used very similar "recipes", so DCR should get you into the ballpark.

Bri

craigmorris74 · 4th August 2005

I just got back to my studio and opened up the unit. Behold the impedence is marked: input 1.5 K and output is 2.2K.
The replacement tank I'm looking at has 1.925K input impedence and 2.575 output impedence (this is the best match I can find). Will this tank work, or will I have to add other parts to match the impedences.

Thanks again,

Craig

brianroth · 4th August 2005

Craig, probably close enough for rock n roll!

Bri

davemoog · 4th April 2008

I've just purchased one of the vintage tube reverbs and am having a problem with one of the tanks. The coils in both tanks measure identical resistance. The tubes seem to amplify and drive equally, yet one of the tanks is quite a bit weaker in output. It almost seems like a problem in the lamination if that is possible. I was wondering if low level was what you were finding or were the coils in your tanks simply open resistance.

And another question how did yours work once you replaced the tanks? Any part numbers handy?

Thanks for any help you can provide.

Dave

30th July 2005	#1
craigmorris74 Gear maniac Joined: Jul 2005 Posts: 270 Thread Starter	Pioneer Reverb-Reverb Tank Replacement I recently aquired a Pioneer SR-101 spring reverb. The reverb tanks on the unit are in bad shape, and I am looking to replace them. I am looking at Accutronics tanks: http://www.accutronicsreverb.com/prodspec.htm Type 8 fits the description of what I need. However, I have no idea what input impedence, output impedence, and what connectors (see bottom of the Accutronics page) are needed for this unit. A schematic for the SR-101 can be found here: http://www.angelfire.com/ky3/craigor...chematics.html Thanks in advance to anyone who can help. Craig

30th July 2005	#2
brianroth Lives for gear Joined: May 2005 Location: Oklahoma City Posts: 1,818	Measure the DC resistance of the input and output coils in the defective tank, then find an Accutronics that matches it as closely as possible. As far as the I/O connectors, I assume there are RCA sockets on the broken tank. The next questions are whether or not the "shell" of the RCA socket is grounded to the chassis or are floating. I just went through that same exercise on a Roland "Chorus Echo" box. Bri __________________ Brian Roth Technical Services Oklahoma City, OK www.BrianRoth.com

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31st July 2005	#4
dharma one Gear maniac Joined: Jan 2005 Location: London Wimbledon Posts: 173	ive been trying to do something similar but vice versa- using accutronics driver schematics with a hammond spring tank. i initially thought the dc resistance would be quite close to the impedance at 1khz but looking at this chart they appear to be quite far off. theres a way of measuring the impedance with a test tone, multimeter and 50k pot but i cant remember it off hand..google should find it

1st August 2005	#5
brianroth Lives for gear Joined: May 2005 Location: Oklahoma City Posts: 1,818	The DC resistance should still be a useful "single point" for comparison. DCR and impedance at 1 kHz will be VERY different. However, Hammond, Accutronics, etc used very similar "recipes", so DCR should get you into the ballpark. Bri

4th August 2005	#6
craigmorris74 Gear maniac Joined: Jul 2005 Posts: 270 Thread Starter	I just got back to my studio and opened up the unit. Behold the impedence is marked: input 1.5 K and output is 2.2K. The replacement tank I'm looking at has 1.925K input impedence and 2.575 output impedence (this is the best match I can find). Will this tank work, or will I have to add other parts to match the impedences. Thanks again, Craig

4th April 2008	#8
davemoog Gear interested Joined: Apr 2008 Posts: 5	I've just purchased one of the vintage tube reverbs and am having a problem with one of the tanks. The coils in both tanks measure identical resistance. The tubes seem to amplify and drive equally, yet one of the tanks is quite a bit weaker in output. It almost seems like a problem in the lamination if that is possible. I was wondering if low level was what you were finding or were the coils in your tanks simply open resistance. And another question how did yours work once you replaced the tanks? Any part numbers handy? Thanks for any help you can provide. Dave