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Old 8th July 2007, 11:34 PM   #21
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Default Re: those transformers looking good with your great amp...

Quote:
Originally posted by cyril_hk
Hi Panson where do you get your transformers, seem likes some kind of low profile version. Looks really great!
Anyway, I just finished mine right early of May, no current limiter too, with all home made PCBs.
http://hk.geocities.com/cyrilwoo/

Cheers
Hi, the transformer is a special order. Your Leach looks great too!
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Old 9th July 2007, 11:04 AM   #22
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Default Re: Re: those transformers looking good with your great amp...

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Originally posted by panson_hk


Hi, the transformer is a special order. Your Leach looks great too!

This low-profile transformer was originally ordered for a low-profile chassis. But I eventually use regular chassis for installing a big (original) heat sink.
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Old 23rd August 2008, 12:26 AM   #23
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hi, panson can you contact me please thru email? I cannot do the same...
Also , that missing 1W measurement would be very cool!! Another question, I found a pdf on www bout an lme49810 front end with Leach output stage, is that yours ? Im fairly sure its yours and Im extremely interested about that one !!
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Old 24th August 2008, 10:40 AM   #24
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Quote:
Originally posted by tritosine
hi, panson can you contact me please thru email? I cannot do the same...
Also , that missing 1W measurement would be very cool!! Another question, I found a pdf on www bout an lme49810 front end with Leach output stage, is that yours ? Im fairly sure its yours and Im extremely interested about that one !!

Here is 1W, 10W and 50W THD vs freq.

Yes, I this is my proposal. Thank you for your interest! I will post results of this project when available.
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Old 24th August 2008, 10:40 AM   #25
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The amplifier (LEACH 150) has an on-board power supply (rectifier and reservoir cap 2200 uF x 8 per rail). I compared the THD of the amplifier for using its on-board supply to using a separate supply which has the same topology with 10000 uF per rail. Interestingly, THD at low freq region associated with the separate supply is better than its counterpart.

I also measured THD for using onboard PSU with an external transformer (same as internal). This helps us to make more meaningful comparison.

It can be seen that using a separate PSU achieves lower THD in low freq. region. It seems obvious the on-board PSU layout responsible to the degraded performance.
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Old 24th August 2008, 04:53 PM   #26
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This is THD for 1W, 10W and 50 W figure.
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Old 16th September 2008, 04:21 AM   #27
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I continue my journey of the above distortion evaluation. The rising low frequency THD is probably due to on-board reservoir capacitors’ charge and re-charges current. The capacitors are located very close to input terminal. They share the same ground plane (top layer). The ground area between +V rail caps and –V rail caps are very noisy. Hence, the input ground is polluted.
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Old 16th September 2008, 04:37 AM   #28
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I measured the waveform between ground A and B. Non-zero PCB resistance given non-zero voltage between A and B when there is current flowing. Since input ground point is in the middle of the current path of A and B, input ground is polluted.

Waveform between point A and B, and distortion residual are shown. You can see the two signals are correlated to some extent.



PS: Distortion residual means remaining signal where the fundamental component is removed.
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Old 15th August 2011, 09:12 PM   #29
Hocdm is offline Hocdm  United States
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I actually have a set of these same blue pcb's I got off ebay a couple of years ago. They came with dc servo boards also. At the time I bought it, it was advertised as a full kit. Once I received only the pcb's I checked the listing again and in small, ultra fine print at the bottom it said "pcb's only." I guess I should have looked everything over more carefully.

I never could find a parts list for the things. Diyzone doesn't seem to exist anymore. Anybody here have a parts list for this clone?
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Old 26th February 2014, 04:40 AM   #30
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Hi. I need that part list too. Please!
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