A guess on what amp this is?
zingo
Posts: 11,258
It's obviously a DIY and looks Rawson to me, but the single output device per channel makes me think chip amp?
Post edited by zingo on
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Scored a nice case anyhow:)
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Not mine yet... :redface:
It's a little hard to see details from the pictures, but it is a nice chassis with components none-the-less. -
my bad....
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Gain clone chip amp,possibly using an LM3886 or LM3875.
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Did you mean fowl? I say..I say..someone stole your innards son.
Give us the run down on this. It looks interesting.Stan
Main 2ch:
Polk LSi15 (DB840 upgrade), Parasound: P/LD-1100, HCA-1000A; Denon: DVD-2910, DRM-800A; Benchmark DAC1, Monster HTS3600-MKII, Grado SR-225i; Technics SL-J2, Parasound PPH-100.
HT:
Marantz SR7010, Polk: RTA11TL (RDO198-1, XO and Damping Upgrades), S4, CS250, PSW110 , Marantz UD5005, Pioneer PL-530, Panasonic TC-P42S60
Other stuff:
Denon: DRA-835R, AVR-888, DCD-660, DRM-700A, DRR-780; Polk: S8, Monitor 5A, 5B, TSi100, RM7, PSW10 (DXi104 upgrade); Pioneer: CT-6R; Onkyo CP-1046F; Ortofon OM5E, Marantz: PM5004, CD5004, CDR-615; Parasound C/PT-600, HCA-800ii, Sony CDP-650ESD, Technics SA 5070, B&W DM601 -
Did you mean fowl? I say..I say..someone stole your innards son.
Foul: adverb
1.
unfairly; contrary to the rules. -
Gain clone chip amp,possibly using an LM3886 or LM3875.
Thanks Fred! Gain clone was my thought based on the looks, but I've never built one, so I thought I'd ask all those who are smarter than me.Give us the run down on this. It looks interesting.
I just purchased it and will have to wait to get it in the mail. No idea about the sound quality, but the build looks decent, and I can always resell it for what I paid. -
Foul: adverb
1.
unfairly; contrary to the rules.
That is the last time I try a Foghorn Leghorn impersonation.Stan
Main 2ch:
Polk LSi15 (DB840 upgrade), Parasound: P/LD-1100, HCA-1000A; Denon: DVD-2910, DRM-800A; Benchmark DAC1, Monster HTS3600-MKII, Grado SR-225i; Technics SL-J2, Parasound PPH-100.
HT:
Marantz SR7010, Polk: RTA11TL (RDO198-1, XO and Damping Upgrades), S4, CS250, PSW110 , Marantz UD5005, Pioneer PL-530, Panasonic TC-P42S60
Other stuff:
Denon: DRA-835R, AVR-888, DCD-660, DRM-700A, DRR-780; Polk: S8, Monitor 5A, 5B, TSi100, RM7, PSW10 (DXi104 upgrade); Pioneer: CT-6R; Onkyo CP-1046F; Ortofon OM5E, Marantz: PM5004, CD5004, CDR-615; Parasound C/PT-600, HCA-800ii, Sony CDP-650ESD, Technics SA 5070, B&W DM601 -
Your Foghorn Leghorn impression is almost as bad as John Travolta's ability to pronounce names... :P
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If built correctly, expect a clean sound without a whole lot of umph."He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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What do you mean by lack of umph? Like 50wpc not much umph? It looks like it has a decent power supply; and non-smps to boot!
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I have a very similar build(non smps too) and it sounded thin in comparison to my Wyred amps...and even the little Pass F5 I had. Fine for the high or mid section of an active setup, or small desktop though."He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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Thanks for the thoughts. Since these chip amps are class A/B, I'll be interested to compare it against similar powered Tripath.
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Well I played "Lets Make a Deal" with the seller since he was semi-local, and I have the amp at my house tonight.
The output devices are one LM3886T per channel, fed by 55VDC, and with an offset of 35mv. Seems well built and we'll see how it sounds! -
I assume 55 vdc total not+ - 55vdc?Otherwise your exceeding a safe value.It does appear to have a decent supply with plenty of filter capacitance and hefty toroid.Many have used these chips with a mere 2000uf or so of filter capacitance.Why they under sized them makes no engineering sense but...
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Correct Fred, 55VDC + to -. The transformer is rated at 340VA, and it's a snubberized PS with 20000uF of capacitance.
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340va.Then you have plenty of transformer and heat sink area to add another pair of modules and make it a 4ch.
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But I only need two channels... Got another idea for single input 4 ohm speakers? :P
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Sure hook 4 modules in 2 sets of parallel(not bridged).That will give you increased current to drive lower impedances.
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That does look like a good option; even Jeff Rowland has an amp based on parallel LM3886s. The amp's been on for an hour and it's not even warm so I'm going to give it a listen and see how this thing sounds.
Thanks Fred! -
After having the amp on for two hours last night, I gave it a listen with a few different albums and was impressed. The LM3886 amplification was clean, detailed, natural, and seemed to have sufficient power. However, I was testing it on a pair of monitors with a subwoofer running bass duty, so that may help the amp keep its composure longer. I'll test it this weekend specifically against my Tripath amp to see how the chips compare, but I do like that the LM3886 has no tweeter hiss associated with class-D.
The amp and circuit was very well built, with star-grounding (and chassis grounding), solid electrical connections, high quality components including Cardas connectors and a Plintron transformer, and proper voltages at all test points with no hum or buzz.
