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Commercial Gainclone kit- building instructions

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#821
i just checked out that polish transformer maker that Peter linked earlier on in the thread, the prices for those transformers are amazingly low! its like 25euros for a 300va 2x24v. Im in germany at the moment, might be a good idea to grab a couple i think. What modifications are worth having done to them? they say they can do the following:

Modifications include but are not limited to: core and coil saturation, electrical (between the coils) and magnetic ( external anti-disturbance screen) shields, enclosures filled with epoxy resin, and vibration-proof mounting.

http://www.toroidy.pl/index.php?option=com_content&task=view&id=6&Itemid=13
 
#822
kele1975 said:
In my case,maybe the value is to low(100uF on chip,and 10uF on rect).What do you think?
Can that be the reason of my problems(five posts above)?
Click to expand...

From what I can gather from your experience, audio nirvana was accomplished with the 2200uf Panasonics running bass and treble. I would say there is your clue. Try adding some 1000 uf-2200uf Panasonics for the treble amp and try your biamp set-up again. If you get the results you desire, then try upgrading the Panasonics to Black Gates, or a mix of the two ...or not.

Some are not happy until 10,000 uf run the woofers, but then they have to fiddle with snubbers and such for sound quality for the mids and tweeters. I believe this is more of a factor with inefficient speaker systems.

Different strokes for different speaker systems I guess. I'm sure you'll find the mix that works for you and your speakers. Fortunately, capacitors are not too horribly expensive for experimenting. Leftovers usually end up in future projects anyway. Always good to have an assortment of extra caps around.
 
#823
Hello 40 watt!

Thank you for your reply.Last night I've changed those 100uF BG STD with 680uF Pana FC,which I had in spare.Difference was immediate.

But I can not take the impression,that simple stereo is a bit cleaner and with more open soundstage,then bi-amp setup.May be subjective impression 🙂
 
#824
Hi

I have finally got round to building my chip amp. i have only wired up one channel so far to test.

I am using a 300va 25v dual secondary transformer with one psu board,one channel and one 8ohm speaker. There appears to be a slight background hum and the occasional crack on high frequencys. any ideas?

I have tried grounding as suggested earlier in this thread, Would installing some of the caps/resistors on the rect board help with this at all?
 
#825
i was wondering for the ease and simplicity of wiring could i use 17g magnet wire for all internal wiring save for the chasis ground? rca to board, board to binding posts, and rectifier board to amp board. (they are still connected)

also where do you buy your nobel pots?
 
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#826
Just completed Peter's Premium LM3875 kit and I'm very happy. Like many others here I'd like to offer a sincere thanks to Peter for his very generous and tireless support of our hobby. Here's a couple of pics of my completed amp.

Regards,
Dan

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.
 
#828
I built these cases myself. They're relatively simple. I just ordered the heatsinks and cut plate aluminum per the instructions in some of Peter's posts. The rest is the use of aluminum angle or square bar to attach the pieces together via various fasteners. The perforated aluminum top is just a snug press fit in with no fasteners. These cases are just another example of Peter's very generous support. He's always available to guide you along no matter what the obstacle.

Regards,
Dan
 
#834
beauistheman said:
ah ok fair enough. Are all switches like that designed the same way? I guess they wouldn't be, some will be on-off, not momentary contact. And the led, how is that powered?
Click to expand...

Based on the information I can find all these switches are Normally Open/momentary contact. The LED has a separate set of leads on the switch. If you look at the AMB Labs power circuit it powers the LED when the circuit is on. Not the only solution but a nice neat one that worked perfectly for me. I chose the Bulgin switch solely for aesthetic reasons. It's a nice looking switch with a nice feel to it. I thought it would make my amp alittle more professional looking.

Regards,
Dan 🙂
 
#839
Hi Peter

I have pretty much completed my first project now. I am using the LM3875 premium in Dual monoblock configuration. I am using 300VA 25v torroids, providing 36v rails. I am also using an ALPS 50k pot and 8ohm speakers.

I have a few issues.

1. The bass appears a bit dull.
2. There is a slight hum.

The only 2 wires i have going to ground are the CHG from each board. Is this correct?

Should the 2 channels be connected to each other in anyway in monoblock configuration?

Thanks for the help.
 
#840
below is my chip amp. layout not ideal i know.....best way i could find to fit it in the chassis i had🙁

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.


Any comments/advice would be appreciated.

Thanks
 
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