Aleph J for Universal Mounting Spec

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6L6

6L6

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lehmanhill said:
values for R7, R8, and R27 are needed.
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R7 - 1K (however, that's the easiest to adjust, merely twist it whatever what you need to set 0V dc on the outputs)

R8 - 1K (I would use a resistor here, not a pot, unless you truly need it)

R27 - 68.2K

In the past, metal film resistors like Panasonic ERX have sounded very detailed but a little cool. Thick film TO-220 resistors like Caddock MP930 have sounded slightly less detailed and a little warmer. Is something like this been experienced in the Aleph?
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Because of expectation bias, yes. :) :) :)
 
lehmanhill

lehmanhill

Member
Joined 2008
Alternate C2, C3

For those of you in Europe, a good choice for a compact C2 and C3 with very good sound quality is the Elna RJH series, 220 uF, 50v. They are available through Elfa-Distrelec. Of course, the shipping to the US is extreme, so I'll be using fat Muse caps, but I would be giving the RJH a try in this amp if I could get them for a reasonable price.
 
J

jrebman

Member
Joined 2007
Just saying hi and checking in -- I have my rev 2 boards from the store, H_A is putting together a semi set for me, and I have a pair of rather large Conrad mf35-151.5 heatsinks in hand already. Plan to build a couple of monoblocks (no room on rack for a stereo amp so the monos sit off to the side closer to the speakers.) I've read most of the last 30 pages of this thread and have a pretty good idea of what to buy.

I'm normally a low power SET tube guy but this amp has caught my attention for a variety of reasons.

Thanks to all of you who have put so much time nd effort into making this such a nice project and I'll be keeping my ears open for the build manual. Lots of experience with tube amp builds, none in several decades with pcbs and SS.

BTW, 6L6 -- I'm just up the road in Boulder.

Thanks again,

Jim
 
6L6

6L6

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jrebman - Monoblocks are a great idea! It keeps the possibility of ground loops down to basically nil! Better isolation, easier to make a really big PSU, it's all good.

I'll shoot you a PM with contact info, I would love to meet up sometime!

-Jim (also)
 
henryve

henryve

Member
Joined 2008
How do I know what is happening with my boards? I pre-ordered boards over a month ago, but have not received any e-mail notification that it has been shipped now that it is in stock. Who would I have to talk to?

EDIT: Oh brother! Never mind. I ordered the new PSU boards also and I see that they still have not hit the store. Now ETA of 31 August.
 
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lehmanhill

lehmanhill

Member
Joined 2008
This Aleph is kind of different from my other experiences. Normally, the cost of electronic components is the big share of the build cost. It is kind of weird to spend so much on power supply (tranny, CLC filter) and cooling, and spend less on transistors, resistors, etc.

Overall, the money is very similar, just different distribution.
 
6L6

6L6

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Funny you should mention that, I'm pricing out a kit to populate the amp PCB, with everything, and it looks like I can sell it for about $70 for the stereo amp.

I've got 30 sets of 2SJ108BL (The same chip as a 2SJ74, but in a different package) And if I can get enough interest, will make the kits.
 
6L6

6L6

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When I visited Foresthill about a month ago, I got a really nice present from Wayne - a bag of 2SJ108BL.

The J108 is the exact same die (chip) as a J74, in a smaller plastic package. The pinout is the same, and the only difference is dissipation, which in our application (the differential input pair of the Aleph J) works just fine.

This has been verified by Nelson. :cool:

After testing the pieces for Idss and matching them, I have enough to sell 30 stereo kits. One kit will populate 2 Aleph J circuit boards, I.E., one stereo amp.

The kit will include Matched IRF240 from Buzzforb, Wima film caps, Nichicon Audio grade electrolytic caps, Dale/Vishay CMF55 and RN60 resistors, Bourns trimpots, and other high-grade components. Everything to stuff the amp PCBs.

There will be no PSU components. (Although, if you are interested, tell me and I will look into it.)

At this time I'm looking to see how much interest the forum has in a parts kit like this. I only have the one batch of Jfets, so there will be only 30 kits. When they are gone, they are gone.

If you would interested in buying a kit, and at this time it looks like it will cost $75USD + shipping, please send me a PM. (I'm only recording interest at this time, not taking orders)

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2SJ74BL left and 2SJ108BL right
 

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Bones13

Bones13

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Joined 2006
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Wow, this amp will take a great leap forward if you put the kits together. I got my jfets from spencer already, and am in the midst of talking with buzzforb. But I think your kit will appeal well to the casual builder (like I really am), I just worried on not ever finding the JFets, so I started looking around.

Is there an electrical/thermal/mechanical reason that the Jfets are zip-tied together during construction?
 
J

jrebman

Member
Joined 2007
Slightly o/t, but I bought a pack of the keratherm insulators for this project and I need to know how to use them. Do you use them alone or with thermal grease -- silicone or berrylium oxide -- and what kind of torque should be used. Never used these before but it seemed like a good time to try them.

-- Jim
 
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