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Old 16th December 2006, 01:35 AM   #1
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Default Heathkit WA-P2 preamp

acquired a pair of Heathkit WA-P2 mono preamps a few years ago and they sat in a box because I wasn't sure what to do with them. I'm a tube noob and have never done any kind of tube project. I'm eventually going to buy one of Shannon's ST-35 boards but I'm still in the learning phase. I figured I may be able to Frankenstien these preamps together and make a decent or at least usable tube preamp. The schematic for this preamp can be found here http://www.angelfire.com/vt/audio/wa_p2_schem.gif These preamps use power off the matching amp which I don't have. I'd have to get some iron and build a power supply. Anyone have any thoughts or ideas on this or should I just start from scratch?
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Old 16th December 2006, 11:40 AM   #2
SY is offline SY  United States
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Before you begin, see what the collector value is- if it's no big deal, then gutting and rebuilding is the way to go. But some of these old, mediocre preamps have astonishing value if left as stock as possible, and the proceeds can pay for a much nicer scratch-build.
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Old 16th December 2006, 01:23 PM   #3
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I was just checking ebay and they have been going for anywhere between $26 for 1 to $107 for a pair. The unique thing about these though is I have the original manuals/assembly instructions from the original builder with construction notes which may or may not drive the value up. The proceeds from the sale of these would pay for about 25% of the cost of a Bottlehead Foreplay. This is probably the direction that I will take because I know what I'm getting into with the Foreplay and someone else may appreciate the Heathkit units much more than I as I am wanting a stereo pre with it's own power supply.
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Old 16th December 2006, 08:30 PM   #4
kevinkr is offline kevinkr  United States
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Before you run off and trash these pre-amps, I just wanted to mention that they are pretty good sounding, particularly for the era. You might want to fix/mod them rather than gut.

Having just read your latest post you might even want to reconsider selling them. Twiddling two volume controls is not that inconvenient actually. (I do all the time.. LOL ) Powering them of course is the big issue.

I suppose though that the Foreplay might still be the best option when I think it out..

Good luck!
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Old 9th May 2014, 01:21 PM   #5
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But they're just so cheap!

Replace this:

Click the image to open in full size.

with this Morgan Jones Modern Baxandall:

Click the image to open in full size.
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Old 9th May 2014, 01:35 PM   #6
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The Heathkit WA-P2, like the Dynaco PAM-1, were powered from an amplifier. Like Kevin already said, powering them would be the first concern. There are some regulated/unregulated supplies available that could do the trick - or else you would have to build something from scratch as an outboard supply.
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Old 9th May 2014, 02:43 PM   #7
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Quote:
Originally Posted by kstagger View Post
The Heathkit WA-P2, like the Dynaco PAM-1, were powered from an amplifier. Like Kevin already said, powering them would be the first concern. There are some regulated/unregulated supplies available that could do the trick - or else you would have to build something from scratch as an outboard supply.
While I have a pair of Heath Williamsons that mate with the WA-P2, but will use a Maida inside the WA-P2 chassis.
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Old 9th May 2014, 03:00 PM   #8
skidave is offline skidave  United States
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Where did that Baxandall circuit come from? I have Jones' books and I don't remember seeing it.
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Old 9th May 2014, 03:14 PM   #9
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It's figure 7.22 of the 4th edition. In the text he shows an EF184, but I use the EF86 as I have a crate-load of them. (It's also similar to the op-amp tone system you see in many applications.)
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Old 9th May 2014, 05:06 PM   #10
skidave is offline skidave  United States
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Thanks!
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