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Old 17th January 2007, 05:21 AM   #121
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Default Re: steal the best

Quote:
Originally posted by Ramandi


I like to go with the best components available . . .

For my diy amps,
my small budget allows me to buy the best components
available here even though they are not world-wide best.

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Old 19th January 2007, 03:11 PM   #122
steenoe is offline steenoe  Denmark
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Quote:
Nelson's is the best, the rest are all mess-around mock-up's.
Absolutely right Patrick, although one mostly sees
Panasonic parts in his amps. Being good solid components, they dont count as being exotic. You dont see outragously expensive parts in Pass amps. As usual, its the circuit that sings, not the parts You can go for expensive audiophile parts throughout and end up with an amp that costs 1/2 a million, sounding a fraction better (with a little good will ) than one costing 2K$.
I am not saying that you should skimp on quality, just that its plain crazy to spend several hundreds of $ on a single cap.
Good solid quality standard parts, is the way forward.

Steen
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Old 21st January 2007, 04:23 PM   #123
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Default Chasing the hum out of my aleph-x

Dear aleph-x builders, maybe one of you can help me with a problem I cannot solve despite reading all your posts.
I recently finsihed a pair of low power aleph-x monoblocks, they both worked at once and sound amazing! Best amps I have built, even compared to my zen V9!
Specs are: 14.3 V rail voltage, one rectifier bridge per channel, CRC filter with 3x 22mF, 0.2 ohm resisitor (5x 1R) followed by 2x22mF caps. 4 IRFP044 per channel, bias is 4A per side, current source set around 50%, relative offset around 20mV. I guess it is a typical low power configuration.
The problem is that one of the channels has a slight hum coming out of my 96db efficient speaker, while the other monoblock is absolutely quiet. By exhanging transformers, power supply, rectifiers and output boards between the two monoblocks I narrowed down the problem to the mainboard of the humming channel.
Here comes the strange thing that puzzles me: When I look at the output of the humming channel I see the following: The there is 100Hz oscillation only at the + output (measured to ground), the - output on the humming monoblock looks just like the + and - outputs of the silent channel. (+ output is the bottom trace and - output the top trace in the picture below). Amplitude of the oscillation is around 20mV.
How can it be that PS noise shows up only on one side (the + in my case) of the output?
Any suggestions for troubleshooting?
Thanks for any ideas.
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Old 21st January 2007, 04:29 PM   #124
Zen Mod is offline Zen Mod  Serbia
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Default Re: Chasing the hum out of my aleph-x

Quote:
Originally posted by 1001meier
Dear aleph-x builders,..................

check input CCS (on top of LTP) and check all tiny parts around output CCS

with "check" I mean- resolder them and-if that didn't help,change them one by one
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Old 21st January 2007, 04:33 PM   #125
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Wow, that's a fast reply.
Just for my information, what is LTP? (CCS I figured out)
So I need to take the shotgun approach....
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Old 21st January 2007, 04:42 PM   #126
Zen Mod is offline Zen Mod  Serbia
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Quote:
Originally posted by 1001meier
Wow, that's a fast reply.
Just for my information, what is LTP? (CCS I figured out)
So I need to take the shotgun approach....

hehe........ya made X and don't know what is LTP.....certainly hole in approach

anyway-LTP means Long Tailed Pair......these two funny mosfets on input of your X....just bellow that input CCS.....
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Old 21st January 2007, 05:16 PM   #127
flg is offline flg  United States
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I am by no means an Aleph X pert But if I recall, this amp has what is know as "Mcmillan" resistors, connected to the sources of the diff pair? Check those
Just a thought...
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Old 21st January 2007, 05:24 PM   #128
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Quote:
Originally posted by Zen Mod



hehe........ya made X and don't know what is LTP.....certainly hole in approach

...exactly, goal is to understand how things work by building them (and troubleshooting).
Thanks for your help!
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Old 21st January 2007, 05:26 PM   #129
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Quote:
Originally posted by flg
I am by no means an Aleph X pert But if I recall, this amp has what is know as "Mcmillan" resistors, connected to the sources of the diff pair? Check those
Just a thought...
yes, good idea. I am using 2.2K "Mcmillan" resistors.
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Old 21st January 2007, 05:42 PM   #130
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Default Re: Re: Chasing the hum out of my aleph-x

Quote:
Originally posted by Zen Mod



check input CCS (on top of LTP) and check all tiny parts around output CCS

with "check" I mean- resolder them and-if that didn't help,change them one by one
One more question after scratching my head: How could input CCS be the culprit since it is shared by both sides and the hum only shows up on + side? Moreover, inputs on - side is free of hum, looks just like + input.
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