Another Very different clone as promised.

[tom wesley]

Here is the second LM 3875 amp i mentioned at the end of my previous post.


This begn life as a disco light i was given by a pub landlord as it kept blowing all the pubs fuses??. (seized motor). Any how i always had the idea of puuting an amp in it and after a couple of years finally did. I bought a 2nd kit from Audio sector for my girlfriend Gemma who did most of the soldereing and made a great job. We then had to very carefully get it in the chassis. This caused a few rows but we got there, only the one heatsink is actually in use with the left channel. The right is mounted further bck on the mounting bracket boss which works fine. the fan runs on a seperate small 12v traffo in PSU box and she wants to mount white LEDS in it now???

I have also shown the PSU which is one of a identical pair i made using a 160va with twin 25v secondariers in a CT type setup with a 35a can type rectifier in the amp chassis. The Psu chassis is saftey grounded which is then taken to the amps pwr star which is the mid point on the neg speaker outs.
Dual inline 3a fuses mounted at rear of PSU and also a IEC outlet lead to power its twin if i build monoblocks.
The light runs off 240v mains and is from a kitchen extractor fan with the added bonus of not being the other side of the traffos.

This amps DC rails are running 38 - 40v do to the PSU giving 27 - 28v ac because of wall V. At this voltage the amp to me sounds more powerfull not in the obvious sense i cant really explain what i mean. My girlfriend uses it at hers along with rack mount active x-over and vintage sonics cabs (8ohm, 20w, 93db @1w/1m). Sounds great and with these extremley sensitive old cabs is V.Loud without any audible distortion. We dont want to damage cabs so re carefull and the fans a must in this chassis!

We wanted the amp to resemble a V-Twin engine and The PC heatsinks work to do this, she is going to spray them i think. All in all a very challenging build but well worth it. This amp is so compact it cn be just picked up and is v. portable so is good for doing small parties etc.

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Gems Internal.JPG

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vamp.JPG

gems V-Amp front.JPG

gems amp back.JPG

[ianpengelly]

Excellent reuse of an old disco light (I am presuming?)!