First of Mark III's with poseidon

[WA4SWJ]

Everyone,

Just completed the first of three Mark III clones with Shannon's poseidon board for a new home theater setup.

Here's a link to a picture:

http://community.webshots.com/photo/354 ... 8377WtkzaP

Worked great the first time I powered it up. Now on to build two more! It took most of one day to build it while puttering around my place also doing other chores.

I can't really tell how it sounds yet. I haven't hooked it up to a decent speaker. Those are Electro Harmonix 6550's, an RCA 12BH7, a GE 5751 and a Sovtek 5AR4 in the background. Transformers are Triode Dynaclones.

Hope everyone had a happy weekend! BTW - at the bottom of the image there is a link called "album". If you click on that it will take you to pictures of the other tube amps I've built so far.

Regards,

[TomMcNally]

It's a beauty Ed ! I'm watching for some more of those chassis on eBay, they look great.

[WA4SWJ]

Tom,

Thanks! It took a while to build but it came out OK. I've got two more to build and I'll finally be ready to finish up the work on the 832 amp. I should post a picture of that one's progress. Maybe later today.

Regards,

[TomMcNally]

I ordered three sets of Mouser parts for my Poseidon boards, but I'm dragging my feet on the transformer sets. I might eBay off some excess stuff first, I have way too much. I hate to part with any vintage stuff, but I have some newer amps that can go.

Make sure you air cool the 832 ! I love the sound, but man, those tubes run hot. We we kidding about you not having to worry about kids or pets getting close to your stuff - I actually caught my cat climbing up and rubbing himself on the hot 832 - enough to cock it in the socket. At least the plate pins were covered, of course, if they weren't - he might not be around to do it again.

... tom

[WA4SWJ]

Tom,

I posted a couple of pictures of my 832 amp. Just click on the link above and under the picture that pops up click on the album link and you can see the 832 amp pictures at the end of the group of photos.

I have some large holes around the tube bases that don't show in the photos. The sockets are mounted a bit below the chassis. I was thinking of mounting a muffin fan inside the chassis on the bottom plate and have it blow air up through. Should work. It would be similar to how some large tubes are cooled in amateur radio linear amps but less powerful.

Can't wait to hear it.

I've been listening to my ST-70 clone all weekend long on a variety of speakers. Man that amp is sweet! It's going to be hard to beat. I'm anxious to hear how a set of the Mark III's with poseidon sound.

Keep your cat out of the audio room!! :o

Regards,

[TomMcNally]

Very sweet ! Did you build the wooden frame for the chassis yourself ? Also - which Hammond power transformer did you go with ? I'm thinking of going up a size or two. Definitely a cat killer ! My cat lays on the bed and listens to music. Vinyl drives him nuts, because the pops and scratches seem to come from all over the room, and he is ready to attack.

... tom

(on the radio at New Jersey 101.5 and looking at stuff on eBay and dreaming of the next project while the kid spins the tunes for me)

http://nj1015.com

[Shannon Parks]

Just completed the first of three Mark III clones with Shannon's poseidon board for a new home theater setup.

Hi Ed,

Beautiful work! I can relate, as I spent a good chunk of this weekend completing a MKIII pair outfitted with red boards for my friend Francois. One had the green driver and the other was stock, so I figured I might as well do a red pair for him as he was gracious enough to lend them for this project. I took fairly comprehensive stock MKIII data as well as Poseidon MKIII data, and I'll try and edit it this week. Should be neat to compare with Tom's Triode MKIII. Just spent awhile this evening breaking them in on the Klipsches, and they sound excellent. Now my ST70 can get on the test bench.

BTW, I really do appreciate these new manufacture chromed chassis. The old Dyna chrome is just a pain to clean up. Forty years of fingers prints aren't very kind, and they look no where near as sharp as your photo. Yellow_Light_Colorz_PDT_21

Shannon

[WA4SWJ]

Tom,

Cool that you're on the radio! Wish I could here you here in the Rochester, NY area.

The 832 amp is being built on a Wellborne Labs base. It's walnut and I still need to finish it - probably with tung oil.

The power transformer is a Hammond 370FX. The OPT's are Hammond 1608's. We'll see how it turns out.

Regards,

[TomMcNally]

Hi Ed -


The Wellborne base is nice - I wish I had some woodworking ability to make something like that myself, but for now the pre-painted black Hammond chassis aren't too bad. I have been pretty good about not scratching them while I cut the holes. My Greenlee chassis punch collection is growing, it seems every variety of the ceramic tube sockets is a different size. I kind of like the 1938 look. hah

You can listen to the station online http://nj1015.com I'm only on once a week - been doing radio since I was 18 and have it in my blood, so every Sunday afternoon from 3 to 7. Full time, I'm chief engineer for a bunch of stations, with transmitters from 35,000 watts down to 250 watts. Nice big tubes - 11,000 volts at 3.5 amps or so on the plates of the big ones.