[mik000000]

Have v/strange problem with pimeta. I have finished amp except for bias transistors. Amp sounds wonderful. I have run it from 2 9v and from a tread set for 24v. I used the opa2132/opa132 opamps. Resisiter bank (r4-r8) is in a dip socket, and I have cleaned the flux from the board.

Voltage measured to all the chips checks out, and Iq is 35ma (without the led). There is no heat from chips and sounds seems perfect.

I also checked resistance between input ground and output ground. I believe this should be inf. When I connect the leads (with meter set to 200k range) the resistance shows approx 80k and then slowly climbs past 200k limit. When I switch meter to 2m range it shows approx 1m resistance and then starts to drop.

Am not sure if this is a problem indicator or just an amomaly of the meter.

Any thoughts?

 

[NeilR]

You're reading resistance across two monolithic amp chips so you're going to get strange results. If it makes you feel any better I'm reading about 4M between input and output ground on my Pimeta, but our configurations are different. My readings were somewhat erratic. Your current draw is reasonable although you didn't specify your buffer configuration.

If you were reading a dead short, that would be something to be concerned about....

If the amp makes nice music you should stop measuring stuff like that and enjoy the music

 

[tomb]

Quote:

Originally Posted by NeilR ... snip ... If the amp makes nice music you should stop measuring stuff like that and enjoy the music

That statement is a whopper. Ditto!

 

[MASantos]

If:

The DC offset is good value <10mV
The current draw is what should be taking into considerations your opamps, buffers, class A, LED
The opamps and buffers are not overheating(you should be able to have you finger on the IC's without burning youself
Voltage checks at the IC sockets
The music is coming out of your headphones.

Then you don't have anything wrong with your amp! Good job!


Quote:

Originally Posted by mik000000 Have v/strange problem with pimeta. I have finished amp except for bias transistors. Amp sounds wonderful. I have run it from 2 9v and from a tread set for 24v. I used the opa2132/opa132 opamps. Resisiter bank (r4-r8) is in a dip socket, and I have cleaned the flux from the board. Voltage measured to all the chips checks out, and Iq is 35ma (without the led). There is no heat from chips and sounds seems perfect. I also checked resistance between input ground and output ground. I believe this should be inf. When I connect the leads (with meter set to 200k range) the resistance shows approx 80k and then slowly climbs past 200k limit. When I switch meter to 2m range it shows approx 1m resistance and then starts to drop. Am not sure if this is a problem indicator or just an amomaly of the meter. Any thoughts?