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Old 13th February 2010, 07:49 PM   #1311
cjkpkg is offline cjkpkg  United States
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OK...more progress...

I have the chassis 99% done...I think I am just down to shortening the leads for the power FETs...

I spent this morning trimming the rest of the wiring and twisting all A/C runs...

The amp is very silent on my Universal Chip Preamp...Haven't tried it with the Aikido yet...and it sounds very nice...

The heatsinks were quite cool so I mounted another pair of 0.47 ohm resistors on the right channel. So it is now running about 2A bias and the heatsink is hot but I can hold my hand on it "indefinitely"...V+/V- is running now at a loaded 15V.
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Old 13th February 2010, 07:55 PM   #1312
jleaman is offline jleaman  Belgium
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Good work, Definatly shorten them fet wires, did you also short the input pins gnd to in- ? that will give you more input gain.

Also, try this, get a decent ( or test ) pot and make a passive volume control, this is what i do with my aleph mini's and i realized how much i am actually missing by using a fancy pre-amp with all the switches and gizmo's.

looks clean in the chassis, also ditch the regular speaker wire for rca connector hook up wire, get some shielded wire, If you don't have any, just get some rca cable or a old microphone cable it will be a-lot better and wont induce hums or noise.
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Old 13th February 2010, 08:22 PM   #1313
cjkpkg is offline cjkpkg  United States
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Yes, I was worried about hum due to proximity with input/output to the input voltage for the PSU...so far so good...it is very quiet. I have it hooked up to some Fostex FE127E eNabld in Fonken cabinets...about 90-91dB efficient.

Also, I am now listening with the Aikido preamp and the gain is a little more and sounds really sweet.

I have grounded the IN- to chassis ground...the gain is remarkable.
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Old 13th February 2010, 08:24 PM   #1314
jleaman is offline jleaman  Belgium
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Quote:
Originally Posted by cjkpkg View Post
Yes, I was worried about hum due to proximity with input/output to the input voltage for the PSU...so far so good...it is very quiet. I have it hooked up to some Fostex FE127E eNabld in Fonken cabinets...about 90-91dB efficient.

Also, I am now listening with the Aikido preamp and the gain is a little more and sounds really sweet.

I have grounded the IN- to chassis ground...the gain is remarkable.
now try it with out a pre-amp and just make a passive volume pot thats what i did, and love it.

Noble pots / alps pots are cheap.
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Old 15th February 2010, 08:24 PM   #1315
cjkpkg is offline cjkpkg  United States
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OK,

Weird thing, I replaced the input and output hookup wire with some shielded cable I had kicking around...belden microphone wire 2 conductor twisted with shield. I now have a fairly noticable hum/buzz coming from both channels.

Where is the best place to ground the -IN to? Should it go to the star ground location or can I run a short wire to the CHGND on the output?

I may try to reposition the toroid too...
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Old 15th February 2010, 08:26 PM   #1316
Tea-Bag is offline Tea-Bag  United States
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It's usually wire placement near the toriod. Try moving the wire around some.
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Old 15th February 2010, 08:48 PM   #1317
udailey is offline udailey  United States
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Put an Alligator clip on it and move it all over.
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Old 16th February 2010, 01:04 AM   #1318
jleaman is offline jleaman  Belgium
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Quote:
Originally Posted by cjkpkg View Post
OK,

Weird thing, I replaced the input and output hookup wire with some shielded cable I had kicking around...belden microphone wire 2 conductor twisted with shield. I now have a fairly noticable hum/buzz coming from both channels.

Where is the best place to ground the -IN to? Should it go to the star ground location or can I run a short wire to the CHGND on the output?

I may try to reposition the toroid too...
Short in- to the gnd spot exactly beside it, there are 3 pins in a row for input,


in+ gnd in- short in- to gnd.
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Old 1st March 2010, 04:34 PM   #1319
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aleph mini. looks not bad
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Old 10th April 2010, 12:44 AM   #1320
cjkpkg is offline cjkpkg  United States
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Allright...

I built an F5 from Peter's boards. I originally tried a 300VA 18V toroid and it was a little anemic - I then acquired a 600VA 18 toroid - a heavy mother...

So I transplanted the 300VA unit into the aleph mini referenced above. It is dead silent and all I can say is that I think it can shoop da whoop as good as the F5. I read about 390mv across the source resistors with .235 resistance.

The heatsinks are HOT...I read about 60C and could barely touch them for a few seconds. It sounds good enough to get a 3U case and use the 2U for a proper preamp case.
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