Commercial Gainclone kit- building instructions

[idjoel2000]

Originally Posted by northernsky

Your expectations depend on your reference and I do not know what is yours.
Concerning my amp, Audiosector premium kit with standard Panasonic caps, I am very satisfied and I found an incredible improvement in sound when compared with my commercial YBA Integrè integrated amp (respected in the audio magazine world and class A on Stereophile during 90s). Finally I got the transparent and natural sound from my Jordan JX92 drivers I heard at audio shows but never realized at my home. I did not realize how important was the amp for the final result.

A main difference between our amp is that, if I well understood, you are using 1 trafo 225VA while I am using a dual mono configuration with 2 trafos 160VA 25VAC.

The only limitation I clearly see of this chipamp is the possible lack of sufficient power in case of low speaker impedence and/or efficiency.

Renato

how is it lack of power when even the amp itself draws less than 2A?

Originally Posted by Peter Daniel

I wouldn't expect any difference with fuses and yes, I would suggest to start with Kiwame for gain setting, BG STD 1000uF at rectifiers and Panasonic FC 100uF on amp board, and then experimenting with different components, if needed.

it was very hard to find riken gold 680R 0.5W at that time, only 560R & 3k3, so i went with audionote tantalum. i thought kiwame would be even worse than the tantalum

i'll try your recommendation on the BG STD first, leave the BG F in place, and see how it sounds. thanks!

will report back soon

[peranders]

Originally Posted by idjoel2000

it's been up and running for more than a week, easily more than 50 hours break in. i'm still not quite satisfied with this amp, as i think this amp sounds not as open as i want it to be (i have really high hope for this amp)

Have you ruled out your signal source? How does it sound with an another amp? The LM38xx is pretty good if you do it right.

[dirkwright]

Originally Posted by peranders

Have you ruled out your signal source? How does it sound with an another amp? The LM38xx is pretty good if you do it right.

Or his speakers? If the amp is set up properly, then it's another problem. Mine is awesome, but my hearing isn't that good anyway...

[northernsky]

Originally Posted by idjoel2000

how is it lack of power when even the amp itself draws less than 2A?

I am not the right person to give technical comments (I can just copy a project at most).
The LM3875 datasheet gives 3.16A peak output current at 40W and 8Ohm loads.

I could verify myself that, even if my chipamp outperforms (in my view) my commercial YBA amp, the YBA provides a much higher sound pressure level: it is rated similarly 50W at 8 Ohm (but 90W at 4Ohm).

Renato

[idjoel2000]

Originally Posted by peranders

Have you ruled out your signal source? How does it sound with an another amp? The LM38xx is pretty good if you do it right.

i'm using my modded dacmagic. it sounds great with my other equipments

btw i'm using headphone, not speaker (very heavy to drive, like AKG K1000. i need to crank the volume od the GC to 1-2 o'clock to get to convenient listening level)

[idjoel2000]

i changed the caps in rectifier board to BG STD now, it sounds much more open!! but the low bass quantity is still less than before. i guess i will just let it run for a while before making any further judgments

after changing the caps, i measured the dc offset on the output of both binding posts. it reads 90 & 94mV on the left and right channel respectively when i set the potentiometer to maximum. is this normal?

[dirkwright]

Originally Posted by idjoel2000

i'm using my modded dacmagic. it sounds great with my other equipments

btw i'm using headphone, not speaker (very heavy to drive, like AKG K1000. i need to crank the volume od the GC to 1-2 o'clock to get to convenient listening level)

That's not right I think. Those headphones have 120ohm impedance and 74dB/volt sensitivity. You should only need a couple of watts to drive them to full output.

[AndrewT]

Originally Posted by dirkwright

..........headphones ...........74dB/volt sensitivity. ..........

Are you sure?

[dirkwright]

Originally Posted by AndrewT

Are you sure?

What are you, the fact police? Why don't you look it up yourself?

Yeah, I made a little mistake, what do you care?

74dB/milliwatt. It makes 107dB with 1 watt input.

Are you happy now?

Please, just go away.

[AndrewT]

Check your posts before abandoning them.