[xTr3Me.aka.Chris]

well do you know how much ohms they have? i got the kit from jeff...

 

[Pars]

Read the stripes or measure them... they should be the default (can't recall what that is).

 

[xTr3Me.aka.Chris]

Well I will messure them tomorrow, im listening atm

I will order some LM78 and 79 L 15 .. the 12 volt model does get quite hot... I mean really hot.

Im still searching for the right ones with TO-220 package.

I will also change the resistors for a lower gain ....
Is there anything I could/should also order for my soha? anything usefull?

greetings

 

[Pars]

These were the ones I ordered for strangedaze39's SOHA:

Mouser #: 511-L7815ABV
Mfr. #: L7815ABV
Desc.: Voltage Regulators 15V 1.0A Positive

Mouser #: 511-L7915CV
Mfr. #: L7915CV
Desc.: Voltage Regulators 15V 1.5A Negative

I don't think you need to use the L version (which IIRC is slightly lower dropout), but I guess it doesn't hurt. I also ordered some Dale RN55s for the gain thing, but did not do that to his amp. I think he may have done it himself per a later thread however.

 

[Ferrari]

TO-220 15V regulator is a "must" when running your amp with JISBOS buffer.
Besides that... some decent coupling caps

(C2 and C14 on SOHA board) can improve the performance of your amp a bit.

 

[xTr3Me.aka.Chris]

Hi,

I already have auri-caps, at least I was told they were good. But tbh I dont believe that amps are so important for sound :X

--
Do i need 1,5A negative regulator or is 1,0A also ok?

I also want a gain of 7, that means I need 100kohm and 50kohm for each jisbo.
I chose some metal-film 1% 1/4W. I will order in 2-3 hours I guess. I hope its ok.
So far I only found 51kohm and 100kohm. Do I need exactly 50kohm or is 51 also ok?

 

[regal]

51k will change the gain about 1/100%, I imagine you won't hear the difference!

 

[Pars]

Quote:

Originally Posted by xTr3Me.aka.Chris /img/forum/go_quote.gif Hi, I already have auri-caps, at least I was told they were good. But tbh I dont believe that amps are so important for sound :X -- Do i need 1,5A negative regulator or is 1,0A also ok? I also want a gain of 7, that means I need 100kohm and 50kohm for each jisbo. I chose some metal-film 1% 1/4W. I will order in 2-3 hours I guess. I hope its ok. So far I only found 51kohm and 100kohm. Do I need exactly 50kohm or is 51 also ok?

49.9k is the usual closest value to 50k in std. 1% metal film range. And no, you would never hear the 1k if you go with the 51k as regal noted.

 

[xTr3Me.aka.Chris]

And about the regulators:

"Do i need 1,5A negative regulator or is 1,0A also ok?"

 

[Pars]

1.0A is fine. I just used the same part type for pos and neg from the same manufacturer, although that isn't required either. Not sure why some are 1.0A and some 1.5A...

 

[xTr3Me.aka.Chris]

Well ok, so I can order now

Thx for your great help!

 

[xTr3Me.aka.Chris]

Well, it seems that I should have ordered the 1.5A Version. MY VR3 is for 1,5 A .. some voltages are wrong on my soha board plus I got a strange hum on my headphones.. I will replace the vr2 with the right 1.5 A version..

edit:
MB the hum ist not because of the wrong vr2..

I just reassambled the old 12volt - voltage regulators and still have the hum. when I change the jisbos with the OPV the hum is gone..

so I have a problem with the jisbos now.. I cant understand why.. I just changed R1 and R2

sometimes I rly hate DIY..

 

[regal]

The regulator isn't your problem

 

[xTr3Me.aka.Chris]

well I changed back to the 15V regulators and improved the connections and soldering..the crazy hum is gone but I still have a very very silent one.

When I turn the alps to about 2 o clock the hum is gone.. but in other positions its getting louder.. strange thing.

i also have about -19V at the -12V point (there should be -15V now..) and +18 at the +12V point (and there should be 15v too)

when I change to the opv the silent hum is gone but then I have a .. "brawl" "murmur", I dont know which word is the right one xD

edit:
The temperature of the tube is only influenced by the tube heater, and then the heater has the right voltage everything is ok right?
cuz the tube is getting very hot since some days oO

 

[Pars]

Quote:

Originally Posted by xTr3Me.aka.Chris /img/forum/go_quote.gif well I changed back to the 15V regulators and improved the connections and soldering..the crazy hum is gone but I still have a very very silent one. When I turn the alps to about 2 o clock the hum is gone.. but in other positions its getting louder.. strange thing. i also have about -19V at the -12V point (there should be -15V now..) and +18 at the +12V point (and there should be 15v too)

Are you sure your meter is working properly now? Measure DC V on a std. battery or something. Do you have the JISBOS boards connected when you are measuring the +12V and -12V points? If so, try disconnecting that and see what they are. Double check your JISBOS boards to make sure you don't have any semiconductors swapped, and that you actually have 2SJ74s and 2SK170s, not all 2SJ74s (the boards that I installed had a parts screw up where it only had 2SJ74s on it... fortunately I had some 2SK170s).

What are you using for a transformer on this?

Quote:

Originally Posted by xTr3Me.aka.Chris /img/forum/go_quote.gif when I change to the opv the silent hum is gone but then I have a .. "brawl" "murmur", I dont know which word is the right one xD edit: The temperature of the tube is only influenced by the tube heater, and then the heater has the right voltage everything is ok right? cuz the tube is getting very hot since some days oO

What is the heater voltage?