• Disclaimer: This Vendor's Forum is a paid-for commercial area. Unlike the rest of diyAudio, the Vendor has complete control of what may or may not be posted in this forum. If you wish to discuss technical matters outside the bounds of what is permitted by the Vendor, please use the non-commercial areas of diyAudio to do so.

Commercial Gainclone kit- building instructions

Jump to Latest
#2,321
Thermal shut down, maybe power supply diode / transistors need heat sinking.
At worst, it was used over its limits, and the chips are permanently damaged, need replacement.
Check the voltages, any above 80% in supply are too much, they means supply volts should be around 80% of max. continuous rating.
Also, see if the capacitors are failing, but the result of that is not consistent.
Check for dried heat sink compound too.
 
#2,322
First thing - check supply voltages, should not be over +\-35Vdc and for your 4-ohm speakers better to be 28-30Vdc.
Second, is this both channels or just one? If only one, then disconnect the one with a problem and test the other channel to ensure it is working properly.
If it is, then use the good channel to compare voltages on the bad board and replace burned/shorted parts to get it running.
 
#2,324
Main filter cap sizing

I built my LM 3875 amps about 8 years ago. Absolutely love it and it has been solid for 8 years! My main filter caps back then were 1000UF at 50V. I recently had some issues with one channel and changed the caps out and the noise went away. I am changing all four out now but saw on here that 1500UF caps were being used. What is the difference and what will the effect be on the sound and does it matter, 1000UF or 1500UF?
 
#2,325
I must apologize for my lack of knowledge as where to post this simple question. >>>I have ordered the LM3875 deluxe kit from AudioSector and there has been no reply in 6 days. Is Peter Daniel still in business, or overwhelmed? Thank you all for your understanding.
 
#2,329
I might have been one of the last customers who got his order filled. Pretty fortunate. I built the amp with no real problems and have been listening for about 10 days now. I am glad that I built this amp. I haven't completed a chassis for it, since I wanted to listen for some time before I went further.
Thanks Peter for a memorable product
 
#2,333
I don't know if the LM3875 that Pete had in stock were matched to each other or not, but I suspect so. I am currently waiting on LM3875 for another build. It is supplied by another source, as is the circuit board. There are some differences that I will have to figure out when it all arrives.
It doesn't look like Pete will be stocking more supplies at this point, and I think that I was the last order filled.
 
#2,336
Peter Daniel said:
By stereo version I mean the use of a single transformer powering both channels. You could still use two separate rectifiers boards, but depending on wiring it may produce hum in some systems, so I always stick with a single rectifier board when using one transformer.

For demonstration purpose, I will install all the boards inside 3 x 1.5" U-channel, 1.25" aluminum extrusion. For normal listening, this is enough to dissipate heat from the chips, and when things get hot, you can always attach it to larger aluminum panel.

I will show a version with a potentiometer, and without, so stay tuned.
Click to expand...
Hi Peter. I am confused about the dimensions of the Al extrusion. I'm getting ready to order the kit and I'd like to order it also. Thanks!
 
#2,339
I need to replace one of the 1500uF Panasonic FC capacitors on my amp board. It was accidentally damaged when it got pushed towards one side. This capacitor is no longer in stock at digikey and Mouser. Is it ok to replace this with a 1800uF Panasonic FC capacitor instead? Are there any other capacitors I should try instead?
 
You must log in or register to reply here.
Top Bottom