Re: Update on LM4780 Amp
You mentioned you run the LM4780 chips in parallel. How about separating them and run each half separately? That would mean only one half of the chip would be used in each amp, the other half disconnected. I'm curious myself how much putting amp channels in parallel affect sound.
Here's the link how to use them in a single chip mode: http://www.diyaudio.com/forums/showthread.php?postid=636565#post636565
okapi said:
You mentioned you run the LM4780 chips in parallel. How about separating them and run each half separately? That would mean only one half of the chip would be used in each amp, the other half disconnected. I'm curious myself how much putting amp channels in parallel affect sound.
Here's the link how to use them in a single chip mode: http://www.diyaudio.com/forums/showthread.php?postid=636565#post636565
Hi peter,
the amps in question are in a relatively completed state that makes me reluctant to go back in and switch them from parallel to stereo.
however, the power supplies are more accessible and i have had some improvements (much better low end) in another amp by increasing my power supply capacitance (tried adding 1500 and 10 000 microF on each rail with a 4.7 microF bypass cap just after the bridge). So i plan to do the same with my LM4780 power supplies.
If that does not work i will try your suggestion. I'll probably experiment with a zobel at the same time as i think my main AC supply may not be the best ( my stereo sounds much better late and night, particularly on weekends).
Tim
the amps in question are in a relatively completed state that makes me reluctant to go back in and switch them from parallel to stereo.
however, the power supplies are more accessible and i have had some improvements (much better low end) in another amp by increasing my power supply capacitance (tried adding 1500 and 10 000 microF on each rail with a 4.7 microF bypass cap just after the bridge). So i plan to do the same with my LM4780 power supplies.
If that does not work i will try your suggestion. I'll probably experiment with a zobel at the same time as i think my main AC supply may not be the best ( my stereo sounds much better late and night, particularly on weekends).
Tim
Thanks for all replys.
Montag, it's really not so complicated. All you need is a piece of copper and a milling machine.
I must say that particle board is just temporarily replacement for plywood - must find some time to cut and paint.
The truth is that I allways liked open designs (like Byob amp) or my TDA1543 NON OS DAC.
Regards;
Montag, it's really not so complicated. All you need is a piece of copper and a milling machine.
I must say that particle board is just temporarily replacement for plywood - must find some time to cut and paint.
The truth is that I allways liked open designs (like Byob amp) or my TDA1543 NON OS DAC.
Regards;
Attachments
okapi said:
Thanks dude
I tried to design a simple cheap design that looks nice. it would have looked better if i used 4 seperate thicker plates and sunk them into the wood. But this is much simpler.
Bascially it is 250x170x55 mm in size. It has a 2200VA toroidal with two lm3886. I used two bridge rectifiers, with 2 x 4700uF per voltage rail. Voltage tests 30V per channel.
Just one dual 50K log pot in front with the standard national application circuit.
I was worries about hum with everything in such a small space but NO hum. Only a slightly audible hiss with volume control at full with ear agains speaker.
I have one LED connected to each voltage rail.
The meranti wood sides ,with clear stain/sealer.
I'll take some photos of the innards and post it.