SOHA II Builders Thread
Apr 1, 2009 at 12:34 AM Post #766 of 1,694
It is not really necessary to solder the heatsinks to the board. The pads are there if someone really needs to do it, but the pins on the transistor (regulators) will hold the devices and heatsinks in place. I left them all unsoldered in my SOHA II.
 
Apr 1, 2009 at 12:37 AM Post #767 of 1,694
Great because I won't be able to do it.

I need confirmation of one more thing so I don't do something stupid. The depression in the top of the op amps mark pin one, correct?

Edit: I just realized pin 1 isn't labeled on the board either. Is it the pin to the left of the indentation on the socket?
 
Apr 1, 2009 at 2:09 AM Post #770 of 1,694
Quote:

Originally Posted by pabbi1 /img/forum/go_quote.gif
Hmmmm - you are using a socket, and not soldering the opamp in directly, yes?


Yes, is this a problem? I am worried about the beginning of your sentence.... "hmmmm."
 
Apr 1, 2009 at 2:39 AM Post #771 of 1,694
Finally received my soha II kit from glassjar - woohoo! The next few weeks is busy time for me but I intend to squeeze a few moments here and there to get this kit together.

Btw, I'm cross checking the parts kit received vs. the BOM and already I'm stuck
biggrin.gif
...can someone clarify where VR+E and Vr-E are? I think they're part of the E12 circuit (TO92) but can't seem to locate where they're suppose to go on the pcb. Thx.

zk
 
Apr 1, 2009 at 4:05 AM Post #775 of 1,694
Egads.
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The problem with the hiss problem is that not everyone has encourntered it. Because of this we haven't been able to pin down a cause. That is, to determine what is differerent about some builds compared to other builds that are using the same components.

At one time I thought it might be noise in the O/P transistors running at 100mA. But I think Ferrari measured this and it was negligible and inaudible.

Is anyone else who has a recent build also having this problem?
 
Apr 1, 2009 at 4:07 AM Post #776 of 1,694
Quote:

Originally Posted by shellylh /img/forum/go_quote.gif
Yes, is this a problem? I am worried about the beginning of your sentence.... "hmmmm."


No. A socket is the best way to go.
smily_headphones1.gif
 
Apr 1, 2009 at 4:17 AM Post #777 of 1,694
I built 2 and I had a minor hiss problem in one of them that had the transformer in the same enclosure. A bit of a twist to the transformer fixed it up.
I have also noticed that the tubes pick up a bit of noise from ground when I put the top cover on the case. The tubes sticking out of the case half way seem to be microphonic enough to pick up noise from the grounded case (on a noisy main line)

I'm not sure if this is the same issue as others have been seeing.
 
Apr 1, 2009 at 5:52 AM Post #778 of 1,694
Quote:

Originally Posted by Computer Blue /img/forum/go_quote.gif
Has anyone solved the hiss yet? I just finished a glassjar kit and have some soft hiss going on. It is there with or without tubes in. Any ideas where to start looking to fix this?


What headphones are you using?
 

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