[sphinxllama]

hi,

just wanted to say that I found my mistake. should have read the link from achina more carefully. did not connect the case with houseground. now I did that there is NO rush when coming close to the tube!
and now

 

[Sathimas]

Hi there,

I was looking for a new headphone amp and came across the SOHA.
I've read this thread from the beginning to the end, along with some
other threads here concerning the SOHA. I found a lot of very useful
information, but I still got 3 Questions ...

My first question will hopefully easy to answer:
I need three LEDs, not only one. I attached a picture of my case.
(At least what it's gonna look like, ain't ready yet. Btw.: I haven't started building, nor ordered any parts yet.)
The two knobs will be backlighted by a red LED each, but therefore I need some current for the LEDs.
Can I simply solder some wire to the soldering spots of the socket LED ?
If the LEDs aren't that bright anymore - no problem, I don't want the Amp to illuminate my whole room

The second question is surely almost impossible to answer

I'm gonna order the level one kit from glassjaraudio, but I want to upgrade the
standard caps that are in the signal path. Jeff wrote that he would order some auricaps.
If I got that right, the caps in C1 and C13 should be exchanged.
Has anybody any expieriences with those caps? I don't want to order the parts from several suppliers,
since the shipping is mostly more expansive than the parts themselves.
Would you suggest upgrading anything else? I don't want to spend too much money.

Also important - I'm living in Germany, so all the extra parts I need will be ordered there.

My third question: grounding ...
As you can see below, my case will my made out of wood and only the front and back panel will be aluminium.
I already saw some pics of SOHAs in wooden cases, so this should be no problem,
but is there anything special to be taken care of concerning the grounding?

Here's the picture:


Cheers,
Sathimas

 

[heatmizer]

jeff will give you some upgrade options on the order form.
c1,c13 and c2,c14

What is the extra knob for?

 

[Sathimas]

Hmm, I already filled out the order form, but there were no upgrades choosable?
I'll try again ... but thank you for the advice.

The extra knob is a source selector.
I'm tired of plugging and unplugging the CD Player, the MP3 Player and the record player.

[EDIT]

Just tried again, since I got no US zip code, I cannot complete the order form.
I'm stuck at the page that tells me to choose the shipping ...
I'll contact Jeff about that.

Any suggestions concerning the caps anyway?
Does anybody have a list of the things Jeff ist offering (and prices)?

Sathimas

 

[headphonejunkie]

On the point of grounding. I use completely wooden case I made myself and have no ground problems at all. Of course if you use a metal case things are different.

 

[heatmizer]

This jeff other site:
http://www.geocities.com/jeffrossel/
Other than that I used nichicon muse es 1000mfd in c1/c13 bypassed with panasonic ecqp and panasonic ecqp on c2/c14
A good build guide is here:
http://www.mb3k.com/soha.html
mb3k also has some alternative caps (boutique) on his BOM

 

[Blooze]

I built mine (p2p version) in an all wood case, but made sure I had safety ground going to all the exposed metal components (ie. tube guard, etc...) that might come in contact with any voltage. Here's a link to pics.

http://www.pedalforroses.homestead.c...phoneamps.html

 

[Sathimas]

I already head seen these sites - but I didn't really understand the BOMs.
I don't know, maybe didn'T to see the wood for the trees

Now I got it - thank you.

About grounding - thank you for the advice to ground all metal parts
that might come in contact with any voltage. I'll keep an eye on that.
@ Blooze - amazing casework - wow.

But what about the LEDs? Is the question that stupid?

 

[Sathimas]

Hello guys, im back.

My SOHA is up and running perfectly now - well, it was running perfectly.

For my test- setup I only used one input, going through a turn-switch
http://www.reichelt.de/?SID=265Sd2ha...ie%2523CUK.pdf
Everything was perfect - what a sound, wonderful.

Today I finally mounted my finished wooden back-side und soldered the other
2 inputs to the switch.
Now I somtimes got some buzzing noise in the background, like the backgroundnoise you have when your radio reception is not perfect.
It seems to be worse on loud notes, quiet tunes do not distort. Eric Claptons Unplugged is nearly flawless,
some Metal CDs I tested are awfully bad...

I got no idea where the problem might be.
Maybe its because I did not solder the ground of any single RCA Jack separately to the Signalground Spots?
I connected the three left ones and soldered them to the left SGL, likewise the right ones.

Hope you got some solution or hint for me.
I was SO happy with my SOHA

 

[Sathimas]

Ok guys, since none of you had any idea about my problem, I had to find out myself ...

Yesterday evening, the distortions where gone when I connected the amp to my CD Player.
Today - they where BACK !

I was about to go crazy... Just 10 minutes after I finally finished the case the amp started making problems again...

Then I began to simply undo anything I did before I reconnected it.
Only 5 minutes later I had the solution:

I'm using a Y-adapter from my CD Player to my Onkyo Receiver and the SOHA,
because always plugging and unplugging the cables bothers me.
If the receiver and the amp are connected I get distortions, if the
Onkyo is not connected - I've got perfect sound!

Now I'm wondering how to get rid of this problem, since I'm still not willing to
steadily change the cables - this disturbs the perfect order behind my receiver
________________________________

I still got one other problem - although I grounded the Alps, I still got a little humming.
Not to loud, but its noticable when I listen to quiet music at a lower level.

Any advice?

 

[Blooze]

Maybe build a switchbox between your sources and amps? This is what I've been thinking of doing. Seems like Nate built a nice switchbox for a headamp show once.

Do you have resistors on the output? I got a little hum on mine without them and went ahead and put 160R resistors on the output. Took care of it.

 

[Sathimas]

I got the 150 Vishay/Dale Resistors on the output.

The hum really annoys me ... I mean I don't here it on 90% of my music anyway, but I still know that it's there.

I don't want to build a switchbox, because of that my SOHA has a source sellector knob

My problem is that I don't have enough room here ...
My Soha Case got rather big and it already covers like 40% of my Onkyo 674.
Since my Receiver gets damn hot, I cannot place anything above the heat source.
Maybe I'll build one if I'd ever posess more than one headamp

 

[heatmizer]

How close is the toroid to the circuit board? needs to be at least 1.5 inches away. I ended up casing the toroid in a metal enclosure to get rid of the quiet hum. My case did not allow me to move the toroid away farther.

 

[Sathimas]

I knew it ... the torriod ...

The torriod is exactly zero inches away from the board,
my case is very small (I had started building it for another amp and wasn't able to change anything anymore.)
and because of that the torroid is kind of stuffed into the case.
I even couldn't mount it horizontal, it has some 40degrees angle to the ground

I'll post some pictures soon.

I'll try to get some thin metal plates and encase the torriod in them.

 

[heatmizer]

Try a tuna can