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Philicorda 22GM751 - Reverb Missing
Philicorda 22GM751 - Reverb Missing
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Old 16th June 2019, 07:55 AM   #1
pelaurendeau is offline pelaurendeau
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Default Philicorda 22GM751 - Reverb Missing

Hello everybody,
I just bought a Philicorda 22GM751. The guy who sold it to me, told me straight away than the reverb wasn't working, but everything else was ok. I didn't had time to open it when I was there and thought also than it could be just a bad component somewhere. But actually, the all spring tank is missing !
I had access to another (fully working) 22GM751 but there is nothing wrote on the tank (like Accutronics tanks).

So my question is, does anybody know the reference of the spring tank, or his impedance in/out, or more easily, what would be a good replacement tank ?

​​​​​​​Thanks !!
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Old 16th June 2019, 08:28 AM   #2
JonSnell Electronic is offline JonSnell Electronic  United Kingdom
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The tank is driven directly from the loudspeaker output on this model, through a matching transformer.
If you select a tank with a medium input impedance, say 800R, that should work fine.
Like this one; Reverb Tank Short 3 Spring Medium Decay 8EB2C1B Guitar Tube Amplifier 800 ohm | eBay
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Old 17th June 2019, 07:30 PM   #3
Mark Tillotson is offline Mark Tillotson
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Quote:
Originally Posted by JonSnell Electronic View Post
The tank is driven directly from the loudspeaker output on this model, through a matching transformer.
That sounded most odd, so I looked up http://modularstudio.nl/docs/PhilicordaGM751.pdf and its true - one speaker amp drives the tank, its output is routed to a different speaker + amp!
Quote:

If you select a tank with a medium input impedance, say 800R, that should work fine.
Like this one; Reverb Tank Short 3 Spring Medium Decay 8EB2C1B Guitar Tube Amplifier 800 ohm | eBay
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Old 18th June 2019, 07:10 AM   #4
pelaurendeau is offline pelaurendeau
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Thanks for the answers !

What about the output impedance ? Does it matter ? I'm not really good with electronic, but if there is a simple way to find the impedance with a VOM on the spring tank of the other Philicorda, I could try !

Also what about the connectors Insulated or Grounded ?

From what I saw on the other Philicorda, it look like a Type 9 spring tank but I have no idea about the decay if it's medium or long, so a 9EB2C1B or 9EB3C1B tank ?
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Old 18th June 2019, 07:42 AM   #5
JonSnell Electronic is offline JonSnell Electronic  United Kingdom
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Older machines used long delay tanks but it is only a matter of taste. Long delay tanks have longer springs.
Output impedance is of no consequence as there is plenty of gain on the pickup side.
The layout is as per the attached, for clarification.
Attached Images
File Type: png Screenshot 2019-06-18 at 08.41.07.png (65.7 KB, 34 views)
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Old 18th June 2019, 07:51 AM   #6
Bill Coltrane is offline Bill Coltrane  Netherlands
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The ideal decay time depends on what you play.


Do you play long sustained chords, use a long delay.
Play stacato, short delay.




Spring reverbs are dirt cheap, diy a switch and you can use several spring reverbs.
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Old 19th June 2019, 01:24 PM   #7
Kay Pirinha is offline Kay Pirinha  Germany
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These reverberation tanks were proprietarily made by Philips for their Philicorda's. They can't be compared to any tank from Accutronics/Belton/Gibbs/Hammond, as they're longer than the short ones, but shorter than the long ones we all know. Maybe 8" to 10" long. And they're open frame, not in a closed can like the Accutronics.


Unfortunately my own Philicorda is stored away, and I don't have the time at the moment to go there, open it and shoot some pics or do measurements .


Best regards!
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Old 20th June 2019, 07:47 AM   #8
pelaurendeau is offline pelaurendeau
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Quote:
Originally Posted by Kay Pirinha View Post
These reverberation tanks were proprietarily made by Philips for their Philicorda's. They can't be compared to any tank from Accutronics/Belton/Gibbs/Hammond, as they're longer than the short ones, but shorter than the long ones we all know. Maybe 8" to 10" long. And they're open frame, not in a closed can like the Accutronics.
That's what I was afraid of .. The tank seemed a bit different to what I'm use to but I thought and hoped the way it's suspended was the only thing really different ..

Well I guess, either I find a dead Philicorda somewhere or I'll have to go for a not original tank and hope it's not to far from the original..
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