[nattonrice]

Would the one that wiatrob supplies with the CTH do?
Perhaps you could ask him if you could pick up two.

 

[regal]

Quote:

Originally Posted by nattonrice /img/forum/go_quote.gif Would the one that wiatrob supplies with the CTH do? Perhaps you could ask him if you could pick up two.

greek to me any links?

 

[nattonrice]

Hehe here the site where you'll see a pic CTH

I'm not sure if that is what you meant though.

 

[regal]

thanks

 

[wiatrob]

regal, am I sending you some? If I'd known it was you...

 

[regal]

Thanks these are hard to find, ought to have Runelight add them to the BOM.

 

[regal]

I'm using big 1uF russion 40 p-i-o coupling caps, would I be better off putting in .22uF vit C's. I initially went with these because my buffer input resistors measured low (around .8 MegOhms.)

 

[runeight]

I don't think you need 1u caps. 800k is a very high input impedance an your low freq response will be subsonic even with 100n. 220n should be more than sufficient.

 

[regal]

I have an "ebay" matched pair of 12AU7 that, well aren't well matched, at the same plate voltage the current differs almost .5mA. What is more important to balancing the gain, the plate voltage or the tail current ?

 

[regal]

One more question, when changing tail current and B+ is the recommended 19V drop across the CCS a minimum? I was always taught that a higher drop is OK ?

 

[FairyTales]

Hi, i've finished building my Soha II and i'm in the initial setup stage.

What i would like to know is if TL+ is ok at 22,5v (i'm on 230v if it change anything)?

Other readings are as follows:

TL+ 22,5V
TL- -15.06V
TH -12.66V
TB+ +117V

I will probably need to bother you guys a few more times before it's completly finished ^^

Thanks

Arnaud

 

[runeight]

Unfortunately, TL+ can't be 22.5V. It is a 15V fixed regulator so there must be something wrong in the PS somewhere in order to get 22.5. We'll have to fix this before you can go any farther with the amp. Could you please check the orientation and values of everything, including the orientation of the vertical diodes. Let's see if you find anything.

 

[FairyTales]

Thanks for the quick reply, so far i've checked the orientation of all the diodes and they are all ok, but i've found a resistor with a value of 2.6kΩ instead of being 30kΩ (R6p) could it be the source of the problem?

I will continue to check the rest of the components, thanks a lot for the help!

Arnaud

Edit:Nevermind it's not coming from the resistor i removed it, checked with the DMM and i get 30kΩ.

. I will continue my investigation, where could it come from if it's not the diodes orientation?
Is there a way to verify the LV+ regulator, i'm getting 26V between the first leg and ground and 22V between ground and the third leg, i was under the impression that it should give me 15V?

 

[runeight]

It could be that the positive regulator is reverse mounted. Or it could be that it's bad. There isn't much else that can go wrong.

 

[FairyTales]

I will try to source another regulator (see the edit in my previous post) tomorrow and see if it solves the problem as everything else seems to be ok.

Thanks for helping me out as i don't really understand how all the bit and pieces works together, i know how to solder and the basic functions of the components but when it comes to solving those kind of issues i'm completely lost.

Arnaud