Foreplay 2 with Paramour

John EH · 4470

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Offline John EH

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on: October 07, 2014, 01:52:57 AM
Fired up a system tonight that I haven't used in a while, my Paramours and an Extended Foreplay 3.  The Foreplay 3 just is not balanced it seems. I ran it through the mill of swapping tubes and cables, right and left, etc, etc, etc.  Always stronger on one side unless you went crazy low on one pot and crazy high on the other.  Clearly it needs a visit to the bench.

Fortunately I have an old Foreplay 2 around. I threw it in the mix and sure enough it the preamp, probably RCA connectors or some pot issue, easy enough to resolve.

Holy Toledo though the Foreplay 2 sounds better to my ears than the Foreplay 3 does.   I'm going to leave it in the system and fix the 3 and use it elsewhere.   At the time the Paramours came out the 2 was in vogue and perhaps just the synergy of the design of the two (as in they were made for each other) is prevalent.

At any rate, wow! What a great system.  Telefunken 12AU7 in the Foreplay, RCA 2A3'S and Sylvania Gold Pin 12AT7's in the Paramours.   I wonder how many years ago I bought this stuff and it's sound is timeless. Haunting with Miles Davis playing.

John



Offline Grainger49

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Reply #1 on: October 07, 2014, 02:37:26 AM
John,

I feel your pain.  I went crazy one week looking for the problem with my crazy imbalance.  I had the speakers out of phase with each other.  I should have recognized that sound, but no!  I checked all sorts of things and finally just looked at plugs on the amps and saw the problem.

It may be time to do some tube swapping to see if anything has gone flat.



Offline Paul Birkeland

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Reply #2 on: October 07, 2014, 06:09:37 AM
The voltages on a Foreplay III are pretty easy to nab, and should provide a clear path for repairs.  (Especially if it isn't an Extended Foreplay III)

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline John EH

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Reply #3 on: October 07, 2014, 09:02:50 AM
The voltages on a Foreplay III are pretty easy to nab, and should provide a clear path for repairs.  (Especially if it isn't an Extended Foreplay III)

-PB

It's an Extended Foreplay.  I'll throw it on the bench some rainy Saturday night.  For now it's low on the priority list. Actually I'll throw it in the Dynaco system downstairs first just to make sure. Been years since I built it but the outputs are all different output levels and #1 doesn't really work at all with lots of buzzing.  2 is a little weird but works, gotta wiggle it around and 3 works but is the quietest output.   I'm pretty certain it's something around the RCA's or pots.  I just need a little time to look at it which is in short supply this week.



Offline Paul Birkeland

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Reply #4 on: October 07, 2014, 07:13:18 PM
Hmm, for the Extended Foreplay, you can measure the "I" and "O" on each of the 3 boards, and Kreg on the middle board.

Those 8 voltages are enough to say whether things are working properly or not.  If you still have MJE-350's, several of these voltages could be wonky.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline John EH

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Reply #5 on: October 07, 2014, 09:25:43 PM
Hmm, for the Extended Foreplay, you can measure the "I" and "O" on each of the 3 boards, and Kreg on the middle board.

Those 8 voltages are enough to say whether things are working properly or not.  If you still have MJE-350's, several of these voltages could be wonky.

Thanks Paul, I figured it out.  The Foreplay 3 is working perfectly and is a thing of beauty the way it is built however a while back I stole the DACT's that I had in there and put them in another project.

Now I'm just going to make up some numbers and letters because it is already installed and operating and I don't remember the actual numbers but I went to the local Japanese store and bought some regular pots to throw in there.

One has a part number of 920 with two rectangle behind it and the other one says 920 E 8.   All other markings are the same and a cursory glance would make you think they are 20 ohm pots.

But in fact one ohms out at 30 ohms and the other ohms out at 20 ohms.    So what I did was take a my meter, made them both 20 and sure enough it's just as balanced as can be.  I'll probably take this opportunity to buy some decent pots and replace them next week or next month or whenever I get around to it.

I remember making the change, and listening to it a few minutes and shutting down.  I hardly ever run the bedroom system until last night when I sat down to do some critical listening.

Just me being stupid.  All C4S diodes lighting pretty and it sounds amazing.

John