Potato Cakes

Update:
The unit is calibrated and sound fantastic!!!
The only problem is the hum .
It's 50hz predominant and depends from output level.
I think it's not heater problem.
Suggestions?
Thanks!

This is same issue I mentioned earlier. My problem turned out it was from the heater, which is why I installed DC heaters for both of my units. The leads from the the transformer and any off board wiring to the heater connections need to be twisted very tight, but you also have to make sure you don't pull out the windings from the transformer.

Thanks!

Paul


ilfungo

Hi Paul
I'm tryng to install dc heater for  6bc8 12ax7 12h7
have you used also for 6AL5?
What power transformer have you used?
My dubt is regardind consumption, because have read the 6.3 consumption is double in DC.

6bc8  400ma
12ax7 300ma
12bh7 300ma
6AL5   300ma

total 1.3A x 2 = 2.6A

My hammond 370x is 2A on 6.3vAC...

Thanks!

Potato Cakes

These are the power transformers I used:

https://www.ebay.com/itm/153854905331?ViewItem=&item=153854905331

Has 3A for the heater winding and an additional winding that can be either 5V or 6.3V rated at 2A. I use the 3A winding which goes to the DC heater circuit which powers all of tubes in the audio path.

Thanks!

Paul

Update:
The unit is calibrated and sound fantastic!!

Could you send any sound sample via PM please?  ::)

ilfungo

Hy Greeok
I'm at home for covid 19 and don't have a samples ut I have a dgi 002 and 176 unit.
If you want send me a vocal sample or what do you want and I can process it for you...

ilfungo

Hi
I'm tryng to resolve the hum, now at accettale level
 but I'm not completly satisfied....
the stange is a 150 hz noise, is the first time i've seen it and the classic 50hz...
see attached...
suggeston please...
It's not heater hum I've tryed dc 6.3 without differences...

ilfungo

Sorry for a stupid question ...
The 12ax7 and 12bh7 are connected in parallel for 6.3 Vac Heater
If I'm not wrong pin 4-5 must joined and we have
6.3 between 9 and 4
6.3 between 9 and 5
Correct?
I've noticed that now pin 4 and 5 are not connected
and I have 6.3v between 9 and 5 and 3v between 9 and 4..

Hey guys, almost done sourcing parts! Looking to see if anyone on here has an API 361 VU Meter, UTC 0-17 Shield and A-33 Shield? Thanks!

Also for those looking for high quality vintage design, I found a 10HY choke made Classic Tones. It's Paper Layer wound like the vintage era ones using premium materials. Made in USA. Here's the link: http://www.classictone.net/40-18082.html

Also found that Aerovox has a new name, its CD Aero. They still sell their capacitors, but still waiting on a reply to see how to purchase. Doesn't look like they have them at retail.

Hoping all the builds are great or are coming along great!

Phrazemaster

Hey guys, almost done sourcing parts! Looking to see if anyone on here has an API 361 VU Meter, UTC 0-17 Shield and A-33 Shield? Thanks!

Also for those looking for high quality vintage design, I found a 10HY choke made Classic Tones. It's Paper Layer wound like the vintage era ones using premium materials. Made in USA. Here's the link: http://www.classictone.net/40-18082.html

Also found that Aerovox has a new name, its CD Aero. They still sell their capacitors, but still waiting on a reply to see how to purchase. Doesn't look like they have them at retail.

Hoping all the builds are great or are coming along great!
PM me if you still need an API meter. Are you in the USA?

Thx,

Mike
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*****
** * Kablooie!

Phrazemaster

By the way - did anyone ever find a clean copy of the schematic? The one I got, an original, is very blurry. Is there a clean crisp copy somewhere? I couldn't find it googling.

Thx,

Mike
***********************
*********************
******************
***************
************
********
*****
** * Kablooie!


Phrazemaster

And one more question - the Hammond 372 X power transformer puts out 620v, split that's 310v x 2. The schematic calls for 325v x 2. Is this a problem?

Thx

Mike
***********************
*********************
******************
***************
************
********
*****
** * Kablooie!


 

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