I read the manual so many times that I know it by heart...
Success in the 4th amp!!
4th one is working great so I guess the first three has a (or
some) components fried. I have to find which one(s).
I guess that if I hear that sound, the LM4780 is working?
In the third amp if I put my ear very close to the speaker I can hear the music which is very very low.
Success in the 4th amp!!
4th one is working great so I guess the first three has a (or
some) components fried. I have to find which one(s).
I guess that if I hear that sound, the LM4780 is working?
In the third amp if I put my ear very close to the speaker I can hear the music which is very very low.
Hi
My amp is running since midle November.
I have easy loudspeakers (8 ohms) 90 db. The amp is dead silent and the sound is good, very good. Very happy with this one. I,m building a second one to biamp the loudspeakers.
Pavel, I made a litle change due to my preamp (passive) – R2,6 - 100K instead of 10K. I Use the noninverting input. Do you think this has any consequence besides a higher input impedance?
It does sound better to me, with my preamp.
Transformer: Torroid, 22x2 V AC, 250VA
Thank you Pavel and Peranders for allowing this project to be shared
My amp is running since midle November.
I have easy loudspeakers (8 ohms) 90 db. The amp is dead silent and the sound is good, very good. Very happy with this one. I,m building a second one to biamp the loudspeakers.
Pavel, I made a litle change due to my preamp (passive) – R2,6 - 100K instead of 10K. I Use the noninverting input. Do you think this has any consequence besides a higher input impedance?
It does sound better to me, with my preamp.
Transformer: Torroid, 22x2 V AC, 250VA
Thank you Pavel and Peranders for allowing this project to be shared
Upupa Epops said:Yes, probably it was crosstalk from other channel...But it is hard with you - soldering is basic knowledge of DIY amateur and nobody can to told to you where is mistake, if something will be uncorrect soldered...
Actually I'm a good solderer.
The problem was I didn't peel off the plastic of L1,L2 (at least I think that was the problem).
I will have to check to first two amps again to see if it's the same problem.
Thanks for the help. The amp sounds good! Very clean sound.
It gets very hot in bridge mode.
Upupa Epops said:Ad R2, R6 : Some opamps are sensitive to Rg unbalance and if isn't the same, distortion rise....It is case of OPA 134 too, so be carefull with listening impressions...
Yes, off course you are right. With a good preamp, it sounds great , stuffed with the original Rg (I listened to it with a good comercial preamp). It is only a temporary solution till i can put together a good preamp. Somehow my passive has dificulties dealing with low impedance input.
Anyway, thanks for the tips. You did a very good work indeed.
I built this amp months ago and it has been left on a shelf waiting for me to find an appropriate PSU to test it. I failed to find one and so yesterday I just connected it up to a trafo with 18V secondaries. The voltages at TP1 and TP2 measured fine and there's not DC offset at TP3 and TP4. So I plugged in some music and it sings.
First impressions are very good. I'm going to leave it running for a few days.
Great job thank you.
Sorry for the wait.
First impressions are very good. I'm going to leave it running for a few days.
Great job thank you.
Sorry for the wait.
C11,c15
Can anyone tell me if the negative leads of c11,and c15 should be facing the relay(center of the pcb). Thank you.
On more quick question I have 2 kinds caps that will fit in these locations:
47uf 50v Panasonic FC or 47uf 25v Elna Starget
Any suggestion on which to use or does it even matter at these locations?
Thanks!
-claiborne
Can anyone tell me if the negative leads of c11,and c15 should be facing the relay(center of the pcb). Thank you.
On more quick question I have 2 kinds caps that will fit in these locations:
47uf 50v Panasonic FC or 47uf 25v Elna Starget
Any suggestion on which to use or does it even matter at these locations?
Thanks!
-claiborne
Pavel,
Can you tell me if the negative leads of (c11,and c15) should face towards the center of the PCB. The polarity of the caps is not marked on the PCB.
Thanks for the quick answer and thanks for such a well designed amp.I am excited to get it working.
I will post some pics as soon as I get it done.
Thank you!
-claiborne
Can you tell me if the negative leads of (c11,and c15) should face towards the center of the PCB. The polarity of the caps is not marked on the PCB.
Thanks for the quick answer and thanks for such a well designed amp.I am excited to get it working.
I will post some pics as soon as I get it done.
Thank you!
-claiborne
Another PA03 finished.
Pavel,
Finally got my amplifier together and I cannot say enough good things about it. It sounds INCREDIBLE!! Thank you very much!
I will comment more when I get it in a permanent enclosure and test it with some good speakers.
I ran it for a little more than an hour last night and the heat sink was barely warm.
If anyone is thinking of building one,go for it. You won't be disappointed.
Here are a few pictures of it. I will post more when I get it in it's enclosure. Thanks again.
-claiborne
Pavel,
Finally got my amplifier together and I cannot say enough good things about it. It sounds INCREDIBLE!! Thank you very much!
I will comment more when I get it in a permanent enclosure and test it with some good speakers.
I ran it for a little more than an hour last night and the heat sink was barely warm.
If anyone is thinking of building one,go for it. You won't be disappointed.
Here are a few pictures of it. I will post more when I get it in it's enclosure. Thanks again.
-claiborne
