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Old 22nd April 2012, 08:33 AM   #401
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I can't believe there is nothing more to discuss about this beauty
So I post a picture of my HT amp 5 L15D's fed by a SMPS1000 from Christi .
I changed the input capacitors with Elna Simic II and the decouplers with Panasonics 820uF low ESR's from RS .
I was a bit dissappointed by the damping factor I measured , only 30 after the 30 amp relays in the DC protection . So I'm upgrading to a FET relay now , still figuring out what FET's to use for the lowest Rdson and reasonable gate capacity .I used 18 AWG wiring for the output , but the longest is only half a feet , so that could't be the reason

As far as the sound , This sounds very good ! on my 3839 Tannoys
There is some noise , but hey , does one stick their ears in a speaker before listening to Nora Jones .
All I can say , from a well experienced listener , this is a good amp !

Attachement doen't work right now , so I post it later ,

Cheers
Rens
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Old 22nd April 2012, 08:50 AM   #402
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Quote:
Originally Posted by doctordata View Post
I can't believe there is nothing more to discuss about this beauty
So I post a picture of my HT amp 5 L15D's fed by a SMPS1000 from Christi .
I changed the input capacitors with Elna Simic II and the decouplers with Panasonics 820uF low ESR's from RS .
I was a bit dissappointed by the damping factor I measured , only 30 after the 30 amp relays in the DC protection . So I'm upgrading to a FET relay now , still figuring out what FET's to use for the lowest Rdson and reasonable gate capacity .I used 18 AWG wiring for the output , but the longest is only half a feet , so that could't be the reason

As far as the sound , This sounds very good ! on my 3839 Tannoys
There is some noise , but hey , does one stick their ears in a speaker before listening to Nora Jones .
All I can say , from a well experienced listener , this is a good amp !

Attachement doen't work right now , so I post it later ,

Cheers
Rens
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File Type: jpg 183.jpg (345.7 KB, 1035 views)
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Old 22nd April 2012, 01:34 PM   #403
zog666 is offline zog666  Australia
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Quote:
Originally Posted by doctordata View Post
I can't believe there is nothing more to discuss about this beauty
So I post a picture of my HT amp 5 L15D's fed by a SMPS1000 from Christi .
wow nice!

I've been using my pair of L20D, powered with a smaller Cristi PSU, switched on all the time (except when we went on holiday) for 5+ months, it continues to be quiet, reliable, and sounding great. I should finish the project, need to make a front panel and tidy up the wiring, but it has been fine "as is".
I haven't upgraded the resistors, haven't had any heat problems, but I'm mostly running at quite low volumes.
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Old 22nd April 2012, 05:12 PM   #404
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Quote:
Originally Posted by doctordata View Post
I can't believe there is nothing more to discuss about this beauty
Hi,
just waiting to free the connex SMPS held back by the customs and I will have something to post.
By the way it's for a 4 channel system, 2 LD20's + 1 tk2050 T2. Hope to get it done before the summer.

BTW nice design!
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Old 22nd April 2012, 08:59 PM   #405
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Quote:
Originally Posted by doctordata View Post
I changed the input capacitors with Elna Simic II and the decouplers with Panasonics 820uF low ESR's from RS .
Did you listen to the amps before the changes?

Quote:
Originally Posted by doctordata View Post
I was a bit dissappointed by the damping factor I measured , only 30 after the 30 amp relays in the DC protection . So I'm upgrading to a FET relay now ,
Why do you think the low damping factor is caused by relay contacts and not the amp module itself?

Nice job on the amp construction.

What kind of case it that?
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Old 23rd April 2012, 05:37 AM   #406
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We did listen to the amp , I have one spare amp and that’s original .
We did some blind AB testing between the original and the modified and we ( The wife and son included ) all found the modified sounding a tat better . A little tighter bass and more transparent .
It was a mono test , so I expect it to be even better in stereo or 5 channel .
I checked the damping factor of the remaining four channels this morning and they were between 80 and 87 . After measuring the relay contact resistance of the low damping channel it was almost 0.120 ohms . I changed it and that solved the problem .
The other relays measured between 28 and 35 milliohms
So in the worst case my Amp internal resistance including the relay and wiring is 8/80=0.1 ohm
If I change the relay with 2 mosfets with an Rdson of 3.5 mOhms in series , my new damping factor will be something like 8/(0.1-0.035+0.007) makes 111 and I’m happy with anything above 100
I made the case myself from two Heat sink profiles I had laying around for the sides , I used 3mm aluminium sheet from the local hardware store for the front , back , bottom and top sprayed it black with a can of spray-paint and used 6mm MDF for the front on top of the 3mm aluminium, again sprayed black and covered with two layers of “Royal coat” decoupage finish satin , that gives an almost perfect ” Brushed” aluminium finish to match my Emotiva UMC-1

I cut a toslink cable in 5 and connected them with some 3 mm PVC tubing to the status LED’s on the amps and the other ends of the 1 mm fibres stick in the MDF front . Looks real good !


I used a plastic kitchen cutting board to mount the SMPS on the bottom of the case to safely isolate the high voltages .


Cheers ,
Rens
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Old 23rd April 2012, 11:27 AM   #407
MrSlim is offline MrSlim  Canada
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Rens,
Very nicely done! I love the creative use of materials and its amazing you were able to get the brushed aluminum look on the front. I also love the Toslink Led extension idea..
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Old 23rd April 2012, 05:20 PM   #408
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Rens,

Thanks for your diligence in before/after listening tests.

Interesting about the bad relay; may I ask which vendor it was from?
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Old 23rd April 2012, 09:39 PM   #409
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I am really impressed with your work, I am an emotiva fan myself and you really pulled off the look just fine.

Good job! Nice build, great detail. The real question... Have you driven all channels to see if the 1000 is enough? I am planning a similar build and keep coming up short on power in my head with a single 1000. I keep thinking linear is the way to go, but SMPS is so much cheaper and smaller. I keep hearing about horible buss pumping on multi channel class d setups, have you checked into it to see how bad yours is?
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Old 24th April 2012, 05:53 AM   #410
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Quote:
Originally Posted by noah katz View Post
Rens,

Thanks for your diligence in before/after listening tests.

Interesting about the bad relay; may I ask which vendor it was from?
I used 3 WLX-7 speaker protection boards from zoe_tsang .
They work pretty good . ( The only mod I made was a 24V zener in series with the flyback diode to improve the off time ) The circuit uses Songle SLA relays . I think I messed up the relay , because I did some pretty abusive testing on this particular one . I simulated 50 Volt rail voltage in an 8 ohm dummy load a couple of times on the input of the circuit and my Lab supply is current limited at 5 Amps . I wanted to be sure it operates as it should , because the Tannoy recones are ridiculous expensive ( and I had quite a few over the years once due to DC on output with my Dynaco Stereo 400 the rest due to much partying )
I tested all other relais , but only once , so they probably survived .
I don't have an unused one , so don't know the original contact resistance .
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