6550/KT88 SET amp aka "Uber Beam Machine"

JoshK · « **Reply #40 on:** 5 Dec 2007, 05:12 pm »

Buddy,

Thanks for the props. When I get it done, I'll have to come over to compare on your single driver speaks. I'm long overdue to pay you a visit anyhow.

jrebman · « **Reply #41 on:** 5 Dec 2007, 05:22 pm »

Josh,

There are also the M-tube series from Mundorf that have values in the same ranges as the motor run caps (tens of uF) and don't cost a fortune.

I think we now have 3 local guys here interested in the SimpleSE 6550 project, so I'll be ordering a few more boards soon.

-- Jim

JoshK · « **Reply #42 on:** 5 Dec 2007, 05:24 pm »

Quote from: jrebman on 5 Dec 2007, 05:22 pm

Josh,

There are also the M-tube series from Mundorf that have values in the same ranges as the motor run caps (tens of uF) and don't cost a fortune.

I think we now have 3 local guys here interested in the SimpleSE 6550 project, so I'll be ordering a few more boards soon.

-- Jim

Would it surprise you if I told you I already have some?

They are pretty much larger values though (10uf, 20uf, 30uf) then what we need for a tuning cap (~ 0.5-2uf) and I am not sure if they are worth the extra money over motor-run caps in filter. That is yet to be seen.

jrebman · « **Reply #43 on:** 5 Dec 2007, 05:28 pm »

Oh, I was thinking filter -- and in addition to motor runs, and primarily to save space while increasing capacity. -- There are only so many 2-1/2" caps you can fit in a normal chassis

and that was my thinking on that.

-- Jim

Wind Chaser · « **Reply #44 on:** 5 Dec 2007, 05:28 pm »

Quote from: JoshK on 5 Dec 2007, 01:22 am

A cheap and simple chassis would be to use a pro bake pan, like these

https://www.surfasonline.com/products/15122.cfm

$23 and pretty thick aluminum and then just add wood trim around the edges and/or paint as is. You can also purchase raw aluminum sheets from onlinemetals.com and just make a top plot and the frame from wood. Options that don't cost an arm and a leg and still turn out nice.

Smart! I like that.

JoshK · « **Reply #45 on:** 5 Dec 2007, 05:33 pm »

Quote from: jrebman on 5 Dec 2007, 05:28 pm

Oh, I was thinking filter -- and in addition to motor runs, and primarily to save space while increasing capacity. -- There are only so many 2-1/2" caps you can fit in a normal chassis and that was my thinking on that.

-- Jim

The tubecaps aren't that much smaller, especially when you use a few of them to build up a normal value for filter. But you could use them in parrallel to the motor-runs. We will likely only need 100uf for filter based on prelim modeling, and you could basically obtain one single motor-run of that value but they are as you say 2.5" or so. The tubecaps are about 1.5" square and a couple inches tall. 80uf motor-run + 20uf tubecap might be something to explore. 80uf motor-runs are more common to come by then 100uf from what I've seen.

jrebman · « **Reply #46 on:** 5 Dec 2007, 06:01 pm »

I've got 2 100 uF and 4 80 uF motor runs on hand, so no worries there.

I didn't realize those M-tubes were so clunky -- but then again, I should have known better than that.

-- Jim

poseidonsvoice · « **Reply #47 on:** 5 Dec 2007, 06:04 pm »

Quote

I see no reason to choose Mundorf in this case.

With the other list of caps you mentioned...I agree!

Anand.

nodiak · « **Reply #48 on:** 6 Dec 2007, 07:01 pm »

Is ~ 1/8" thick aluminum plate good for top and back plates? I can get it cheap at local scrap yard.
The rest of chasis would be wood.

JoshK · « **Reply #49 on:** 6 Dec 2007, 07:08 pm »

that is good enough I'd think. If for some reason you need more support you can support it with wood or brackets.

jrebman · « **Reply #50 on:** 6 Dec 2007, 07:16 pm »

Don,

Is it 6061-T6? If so, it should be more than adequate as I once built a new floor to replace a rotted out one in an ancient pickup truck. By the time the truck went to it's final resting place, the aluminum floor was the only part left intact

.

-- Jim

BTW, the Welborne amps use a .090 aluminum top plate, and yours is .125, so really, no problem.

-- Jim

nodiak · « **Reply #51 on:** 6 Dec 2007, 07:39 pm »

OK, I'll eye this as the minimum thickness, may go thicker. I'm going to go ahead and make a parts list for the SimpleSE, tho not sure when can get to it.
Jim, not sure if it's T6, but yes it should outlast the rest. Once anodized a piece of aluminum for a sculpture (art class), but will likely go with powder coating this.
Josh, parts look nice, looks like a tater masher 5r4. I like the chasis size, gives some space between components, makes the amp look more confident.

JoshK · « **Reply #52 on:** 6 Dec 2007, 07:59 pm »

tangent....
My wife saw some pictures of Electroluv's gear the other day cause I showed her. She used to be into metal arts and even worked as a jeweler for a year before going to college. She briefly got excited about the possibility of working together to make artistic audio gear.

Back to reality...
I'd love to learn how to anodize and powder coat. I vague know it has to do with electro-chemical process, but that is it. I think though that my wife would allow me to invest in some such equipment since it can be used for her hobby too (jewelry work).

For this project I am thinking about oil rubbed copper look. I haven't seen it done in audio yet and think it would look bitching. I have copper plates (old copper shingles off ebay) to use. They will likely need to be reinforced with support underneath since they are a bit thinner and bendable than the aluminum I have.

nodiak · « **Reply #53 on:** 6 Dec 2007, 08:35 pm »

Googled electonluv, whoa, hadn't come across that yet. Could be fun to give more focus to visuals for sure, go more sculptural. I always thought some tube amps have a real cityscape look to them...could go off on that.

JoshK · « **Reply #54 on:** 6 Dec 2007, 08:49 pm »

But as you might imagine, his prices will make you go whoa too. Still very cool stuff and if I was going to ever spend big bucks on hi-fi that would be it.

Gordy · « **Reply #55 on:** 6 Dec 2007, 09:30 pm »

Josh,

Powder coating is quite easy actually, not unlike spray painting, except you need a charging system to adhere the powder to the parts and the electrostatic powder gun.... and you need an outdoor oven! I used to have a small commercial set up at work for testing pigment but, we put it in storage quite some time ago. All in all, it's just too inexpensive to have a commercial shop do it for you. My local guy painted two speaker stands for $40 once he know I was a hobbyist and I was supplying my own powder. I can't imagine a single plate or two running much more that $10-15....

JoshK · « **Reply #56 on:** 6 Dec 2007, 10:21 pm »

Thanks Gordy. I did some poking about and saw powder coating gear for about $300 or less but you need the outside oven like you said. Plus I really want to try the patinization on brass/copper. Onlinemetals sells sheets of brass. You could get the 12" x 36" and have them cut it in half making 2 12" x 18" pieces for two amps. This would cost about $80 each piece, so not cheap. But I have the copper sheets to work with first.

DaveC113 · « **Reply #57 on:** 7 Dec 2007, 12:22 am »

When I had my welding / auto shop the local powder coater gave me very inexpensive rates if I picked a color he already had on his schedule and ran my parts with others... Its an industrial process, and can look ok, but not as good as auto paint. You can also buy anodizing equipment to use at home, that is an electrochemical process... both ano and pc can be done at home pretty easily, but unless you are using it a lot or are just relly into doing it I'd suggest having it done locally. Another option is using a dremel or angle grinder with a fine stainless steel brush to brush the aluminum, then clear coat it with spray paint. Polishing is possible too, but its too much of a pita..

I had Jim order me a SimpleSE board, looks like a great project... most of the small SE kits just don't have enough power, and 300Bs are out of my price range. The TS 6550 seems like a great alternative. I like the James OPT suggestion, what about a ps transformer? The Chicago unit?

Also, (a bit off topic) I just got some of the Low Noise Russian Military NOS Reflektor 6922 tubes for my preamp. They are very good, at least compared to the NOS Brimar and Sovtecs I have to compare them to. At a fraction of the price of the sought after NOS tubes, they are a good deal too.

Dave

JoshK · « **Reply #58 on:** 7 Dec 2007, 12:30 am »

I think the Chicago power transformer is going to turn out to be the one I advise people to get for this project if its within their reach. Its a bit more expensive then a similar Hammond but it is made a lot nicer IMO. Fully potted, oversized core, plenty of filament current. I think that is worth a bit extra, but not everyone might agree. That is why when it comes to part selection, I will list options and suggestions for what I think it worth the extra and what is best for budget.

Those NOS 6922 Reflektors labeled 6N23P? Get them from fleabay?

DaveC113 · « **Reply #59 on:** 7 Dec 2007, 02:36 am »

Quote from: JoshK on 7 Dec 2007, 12:30 am

I think the Chicago power transformer is going to turn out to be the one I advise people to get for this project if its within their reach. Its a bit more expensive then a similar Hammond but it is made a lot nicer IMO. Fully potted, oversized core, plenty of filament current. I think that is worth a bit extra, but not everyone might agree. That is why when it comes to part selection, I will list options and suggestions for what I think it worth the extra and what is best for budget.

Those NOS 6922 Reflektors labeled 6N23P? Get them from fleabay?

Hmmm, maybe I can manage to get some transformers for xmas...

Yes, the tubes are the 6n23p, they were recommended by partsconnexion, $45 / MP. If you have a preamp that uses them, they're worth a try.

Dave