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Old 8th March 2009, 07:22 PM   #991
Tripmaster is offline Tripmaster  United Kingdom
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Quote:
Originally posted by audio1st
Hi,

Just finished fitting "Pedja's Discrete regulator" into my LM1875 Amp.. Had to end up using four, 25V, 30VA transformers because space was tight, (and I had them already ).
Loving the sound, a match made in heaven ..
Hi Barry

How has the sound improved when compared to your previous supply?

Ive yet to hook-up my discretes

Richard
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Old 8th March 2009, 08:48 PM   #992
Beftus is offline Beftus  Netherlands
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Quote:
Originally posted by Rainwulf


You should use much thicker wire for the PSU to amp hookup. You are saying that you are using .6mm for that link, yet using much thicker cable for the amp output... the PSU links are supplying that current you are so carefully trying to NOT limit using that thick cable at the output. You need to make the psu links as big, or even thicker, otherwise their resistance will limit your current from the psu to amp, and in the same vein, where is the earth return from the amp modules to the PSU?


The pictures show an early stage, earthing has been added since. WRT the thickness of the PSU links, please enlighten me, how much resistance would I lose if I were to use the thicker wire for the PSU links? I have a gut feeling that the loss in resistance is negligible, the links being so short in lenght. Would I be able to measure that difference with a DMM?
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Old 9th March 2009, 09:13 AM   #993
audio1st is offline audio1st  United Kingdom
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Quote:
Originally posted by Tripmaster


Hi Barry

How has the sound improved when compared to your previous supply?

Ive yet to hook-up my discretes

Richard
Hi Richard,

The difference that I have noticed is improved bass.
It's not lower (12ft x 12ft room), you just know it's there, not bloated either, controlled.
The mid's are as smooth as ever and the treble is bright, without distress.

I wasn't after mega bass and high volume, mainly late night listening.

Feeding the amp with 25vDC (same as previous), still no Ci (feedback cap), DC offset of 5mV each channel. Using with Active pre-amp.
Runs warmer than I remember, may just be the regulator sharing the heat-sink (case).

The relays on the speaker's output, are on a simple time delay (from Nick's website). This may be replaced with a speaker protection circuit. The LM1875, I have found, suffers from power on/off pops and clicks, the delay speaker turn on and instant turn off cures this.

Barry.
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Old 9th March 2009, 11:00 AM   #994
androuski is offline androuski  France
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I've also noticed a ploc from my LM1875 amp.
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Old 14th March 2009, 06:31 PM   #995
VictoriaGuy is offline VictoriaGuy  Canada
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Default my ref revC- my build

Finished up my chipamp a few days ago.
Many thanks to Mauro Penasa for a great design, and to Uriah and Peter who organized the recent group buy. Also to all the folks who contribute to the posts here- lots to learn.

It sounds excelllent and went together without any problems.

Case/chassis/transformer/heatsink is a recycled thrift store Sansui receiver.
Garry oak with tung oil finish.

It'll take a few messages to attach the pics, since the forum doesn't allow multiple attachments.

Cheers
John
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Old 14th March 2009, 06:32 PM   #996
VictoriaGuy is offline VictoriaGuy  Canada
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Default my ref revC- my build

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Old 14th March 2009, 06:36 PM   #997
VictoriaGuy is offline VictoriaGuy  Canada
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Old 14th March 2009, 06:38 PM   #998
VictoriaGuy is offline VictoriaGuy  Canada
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Old 14th March 2009, 06:39 PM   #999
VictoriaGuy is offline VictoriaGuy  Canada
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Old 14th March 2009, 06:41 PM   #1000
VictoriaGuy is offline VictoriaGuy  Canada
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