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SOHA II Builders Thread - Page 52

post #766 of 1686
Thread Starter 
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.
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #767 of 1686
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?
post #768 of 1686
Thread Starter 
Correct.
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #769 of 1686
Thanks. Didn't want to screw that up.
post #770 of 1686
Quote:
Originally Posted by pabbi1 View Post
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."
post #771 of 1686
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 ...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
post #772 of 1686
I believe they are LV-E and LV+E on the silkscreen.. they are TO-92's correct?
post #773 of 1686
wiatrob, yep they're TO92's... I see them (LV-E and LV+E) on the board, thanks!

zk
post #774 of 1686
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?
post #775 of 1686
Thread Starter 
Egads.

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?
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #776 of 1686
Thread Starter 
Quote:
Originally Posted by shellylh View Post
Yes, is this a problem? I am worried about the beginning of your sentence.... "hmmmm."
No. A socket is the best way to go.
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #777 of 1686
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.
post #778 of 1686
Quote:
Originally Posted by Computer Blue View Post
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?
post #779 of 1686
What slot does the board go into to match the face plate diagram? And does anyone know what size standoff works with that slot?
post #780 of 1686
Thread Starter 
Third from the bottom.
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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