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Topic: Early Session 400 Reverb Tank |
Larry Bell
From:
Englewood, Florida
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Posted 12 Jun 2000 5:49 am |
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Anybody have the Accutronics part # for the reverb in a late 70s (78-79) Session 400? Is it a 'Type 8' or 'Type 9'? (or none of the above)
you may want to refer to
http://www.tubesandmore.com/17250.html
(a really good source . . . IF you know what you're looking for.  )
Thanks in advance.
LTB |
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Jon Light
From:
Saugerties, NY
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Posted 12 Jun 2000 10:06 am
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| Hey Larry--I suspect that the fact that my 1986 Session 400 has a type 9 tank is not useful information but.....I don't know how to end this sentence |
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Jon Light
From:
Saugerties, NY
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 14 Jun 2000 2:23 pm
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Larry,
If you have the old unit, you will find the part number rubber-stamped on the top. It will be a 7 digit number, and the first digit indicates the type. Also, the type 8 was rather small (only 9-1/4" long). The type 9 and type 4 are 16-3/4" long. Make sure you get the replacement that has the right input impedance (they vary from 10-1900 ohms). A substantial difference in impedance might not perform as well. Maybe some of our other electronics experts could tell you exactly, but I imagine that it would be better to get a higher impedance if you couldn't get the right value, that way the input circuit would not be "loaded down". |
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Larry Bell
From:
Englewood, Florida
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Posted 14 Jun 2000 3:22 pm
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Jon - thanks for the info, Bud. Good stuff.
Donny - problem is that the patent numbers and stuff are stamped into the metal but the model # is ink-stamped on and it's ILLEGIBLE. I was hoping Mike Brown might just pull the spec off of the schematic (I assume it would be there but don't have one, unfortunately). Maybe I'll just have to call him. I bought one from the link in my original post and just guessed on one of the two that were listed for Peavey amps. You get a little reverb but not near as much as with the original tank (which is shot). It is a three-spring Type 9AB2C1B which, according to Jon's link to Accutronics, is
Type 9 -- 10 ohm (lowest value available) input -- 2575 ohm output -- medium delay time -- input insulated / output grounded -- no lock -- mounted horizontally w/open side facing down (--whew!--). I have no idea what it was designed to accept. What I got is obviously not right.
Other ideas?
THANKS
LTB |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 14 Jun 2000 7:45 pm
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Larry, the type 9AB2C1B you have is a full-size, 6-spring unit, and should have plenty of reverb. I would suspect the problem is that the amp you have is designed for a much higher input impedance than 10 ohms, which is the spec. for the one you bought.
The 1475 ohm unit 4FD3D1B is probably what you are looking for. This is the general replacement type with long delay. Check with Mike Brown to be sure about this, though. |
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Jon Light
From:
Saugerties, NY
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Posted 15 Jun 2000 2:04 am
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Larry--my deepest apologies--I read the specs way too fast and thought that my 16" tank automatically made it a type nine (I only compared specs of 8 vs. 9)
My tank is indeed type 4--#4EB2C1B
The reason I wrote my first post, BTW, was that I didn't know if my later model '86 400 would have the same specs as your older amp. |
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