829B amps with Poseidon Boards are finished

for Dynaco Mark II/III/IV and DIY PP monoblocks

829B amps with Poseidon Boards are finished

Postby audiowize » Tue Jan 01, 2008 9:41 pm

Image
Shot with E5700 at 2008-01-01
Image
Shot with E5700 at 2008-01-01
Boy, these took a very, very long time. I used the Posiedon boards setup for the MKIV voltages, and I removed the balance pot and a few other parts to allow independent tube biasing. Other than dropping some voltage by reducing the input cap, these babies are all finished. I thank all of you on here for the help you've provided. These boards are VERY stable, and super fluid in these amps. I've settled on the ECC803S new release Tung Sol for the input tube, and I'm running some gold pin E80CC's for the phase splitter. The rectifiers on these are dual 5U4's. With the dropped voltage, I'm looking at ideally being around 365VDC on the plates, and around 105ma at idle per 829b.
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Postby WA4SWJ » Wed Jan 02, 2008 6:09 am

audiowize,

Very nice looking amps. They are kind of hard to see. The photos are a little dark. Care to take them out of the rack and post some close up shots? I built an 832 amp (so has Tom McNally) and I like it a lot. Also, I like the plate wire caps you have. Where did you get them? I just used some plug-in terminal block parts removed from a Phoenix Contact terminal block and they're not nearly as nice looking.

I have some 829B's laying around waiting for some kind of project. This looks like a good idea for them.

Nice job indeed. I hope they sound great and that you're enjoying them. Something to be proud of!!

Regards,
Ed Long
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Postby crispycircuit » Wed Jan 02, 2008 9:28 am

Thanks for the pics. Awesome amps! I'm always amazed at the talent, dedication, and knowledge of DIY enthusiasts. I encourage pics of all projects big and small. These pics also kick my ass into gear! and I thankyou.......
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Postby TomMcNally » Wed Jan 02, 2008 11:42 am

Very nice looking amp. I love the sound of my 832A amp,
looking at yours makes me want to tweak it. My plate
voltage is too high.
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Postby audiowize » Fri Jan 04, 2008 3:45 pm

Yeah, high plate voltage doesn't help the sound too much of these. I will yank one out tonight and take some detailed shots. I built the chassis in such a way that the Poseidon board is very difficult to even see unless you remove two metal cover plates. I find that hiding the places where wires are soldered to PC boards makes for a cleaner internal appearance.
-Paul
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Postby audiowize » Sat Jan 05, 2008 12:16 am

I openned these guys up today and reoptimized them for proper B+. I shot for ~360 VDC, and I'm getting 356 on one, and 353 on the other, not bad in my book.

Here are some better shots:
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Inside shot. This shows the Russian PIO caps I used on the cap input (and the Solens that trim the voltage up a tad).

Image

This is a top down view. The cover on the driver is spaced off with 3/8" standoffs.
Image

Now you can see the Poseidon board. A few parts were omitted, some values were adjusted ever so slightly.

Image
Shot with E5700 at 2008-01-04

One last shot of the pair.
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Postby WA4SWJ » Sat Jan 05, 2008 1:06 pm

Fantastic! Thanks for the up close pics. Very nice job indeed. I like how you built these. Are you happy with the sound? I'm sure you probably are.
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Postby kimbob » Fri Jun 20, 2008 3:02 pm

Beautiful work!
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