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-   -   An illustrated guide for Aleph 60 builders (http://www.diyaudio.com/forums/pass-labs/227444-illustrated-guide-aleph-60-builders.html)

PKI 10th January 2013 01:34 AM

An illustrated guide for Aleph 60 builders
 
see below...

PKI 10th January 2013 04:12 PM

10 Attachment(s)
This thread is inspired by 6L6 and his very useful instruction (thanks, my older DIY buddy for all you help :-)! ): An illustrated guide to building an F5 - diyAudio
My original building thread is here: http://www.diyaudio.com/forums/pass-...ng-thread.html, but pictures worth MORE than words, indeed.

First of all I'd like to thank all members of this great forum, you all helped me and inspired me in one or other way :-). However(not a secret here :-), that my real supervisors are: Zen Mod and of cause Nelson. It is hard to tell how thankful I am. You can be sure, that you always get your "Thank you!" whenever I turn music on and have a pleasant smile on my face! :-)

Lets start:
I wanted to build an amp to drive my Infinity Renaissance 80, so after thinking and asking I decided — a pair of Aleph 60 monoblocks.

Parts:
1) Heatsinks: two(per monoblock) 5U 300mm with 0.2 c/w from hifi2000.it modushop.biz.
Shipping was very fast (like three days from Italy!)
2) Aluminum: cut to size from: The Best Place To Buy Metals & Industrial Supplies Online | Buy Metals Online | Buy Industrial Supplies Online | Cut to Size | No Minimum Order | CNC Laser Cutting | CNC Machining
Nice, but little bit expensive I think.
3) Transformers: 600VA@25V from: Antek - AN-6225
4) PSU caps: 4x100k@ uF/ch Uni-Chem from digikey: E36D500LPN104TEA5M United Chemi-Con | 565-3323-ND | DigiKey
5) PCB's: from chipamp: Order | Chipamp.com
6) Transistors: IRF244 and zvp3310 (FE) from our user h_a. You can PM him.
All other small stuff: ebay for wires and Digikey and Mouser for components.

Construction:
1) Chassis:
I do not have instruments except a wireless drill and small hand stuff, so constructing enclosures were the longest and least pleasant experience for me.
Especially enjoyed tapping: broke 5 tap because of excitement :-). Do not buy cheap taps they made of sh..t, not steel :-). For vent slots I found a guy with a milling machine who helped me.
After all here what i got (pictures 1, 2):


2) PSU mounting and wiring:
I used description from 6L6 thread, there is everything in there.
The only difference I had another type of caps — screw terminals. So,
— use an aluminum plate to connect capacitors like this: +(-+)- and 0.15Ohm 25W resistors for CRC filtering.
— after second pair of big cans I installed 4.7uF Wima MKP4 PP caps and 3k3 3W bleeders.
— drill two holes on this aluminum plate for the input voltage and one right in the middle on the opposite side for a ground star (pictures 3, 4(green wires to go a blue LED)):

3)Transistors mounting and wiring:
I used 6-32 taps to mount both boards and transistors on the sinks (see above how I enjoyed it :-).
For an Aleph 60 you need 6 pairs of output transistors, however, chipamp(BrianGT) pcb's gave only 3+3 daughter boards. So, you can either

— buy another set and connect two daughter boards together with wires (what I did)
— buy two extra output boards for SE BA amp from the store: P-BASO-2V20 - Extra pair of Single-Ended Output boards (Requires gain stage and bias boards; Makes 2 channels; Rev 2.0) - Burning Amplifier Series - Power Amplifiers - PCBs (what I would do now)

As thermo-conductive insulators for transistors I used aluminum oxide pads and non-conductive grease(paste) from Mouser (picture 5). They have many, choose your own!
So, here are some pics of my almost assembled amp with fired up PSU (see blue light! :-), picture 6, 7. Looks almost like a real amp, doesn't it? :-)

4) Populating and soldering:
— here is the original schematics with BrianGT notation (see, ZM, I had it from the beginning! ;-), picture 8.
— I use all parts from original schematics except: R11 — 500Ohm trim, R19 —200k trim, R21 — 2k trim and C20 — 12pF.
— bypassed 220uf Silmic II with Vishay MKP 1837

Thats pretty much it. Oh, do nit forget to put a jumper between -in and gnd if you use RCA (yep, did this mistake ;-). Picture 9.

PKI 10th January 2013 04:17 PM

Quote:

Originally Posted by Zen Mod (Post 3319184)
;)

did you chew on conversion to cascoded Jfet FE ?

I think F6 and F5Tv2 first! :-) I want Aleph with SemiSouth in the output :-(

6L6 10th January 2013 04:19 PM

Merge the text and photos yourself in the next few posts and then ask the Mods to delete all the old stuff.

AudioSan 10th January 2013 04:24 PM

this chassis looks very nice and clean:) but 1 question. are you running the LED's directly from +32V without any resistor in series?

PKI 10th January 2013 04:37 PM

Thanks AudioSan, no there is a 4k75 resistor hiding next to the ring crimp. Otherwise, it would be a bright LED :-)

AudioSan 10th January 2013 04:39 PM

aha. yes. i that's what i was thinking:D

PKI 10th January 2013 05:15 PM

4 Attachment(s)
Adjustments and listening:

It was a long story for me( and, I guess, ZM :-):

I messed up with input transistors and put not matched in Q1 and Q2 position
However, most important thing was bias and AC gain:

I bias my amp at 0.44A per device that gives me 2.64A total
I was playing with AC gain and found that with my speakers you need to go lower than 50%. Sorry, do not know how I was using my ears as a tool :-).

Now the amp sounds so wonderful! I love the tone, midrange, bass control and crystal hight, you know... What people say about Alephs true. Build one and you will love it.
Here are some (showing off) photos :-):

Zen Mod 10th January 2013 05:45 PM

:clown:

did I said - Fugly! ?

toufu 10th January 2013 05:47 PM

Hi PKI, I just built an Aleph 30 using BrainGT's board. I am using his spreadsheet for the BOM. Can you list the changes to make to make it into an Aleph 60? Thanks.


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