[Cloud]

i will go back and check.  i got a nudging feeling i got the wrong VA for the transformer. I might have gotten 15VA thus for each of the secondary its only 500mA. if thats the case, i dont know what else to say but sorry x 10 in having my carelessness for wasting your and regal's time in helping me to troubleshoot. 

 

[runeight]

If that's the case, no apologies at all are necessary. I'd just be happy that you can get the amp back working again with a newer better transformer.

 

[Cloud]

turn out that the transformer was as spec. I removed all the wiring and reconnected them and TB+ was back to 100V+. good news!
 
however, another problem surfaced. e12 keeps turning on and off, on and off in a cyclic pattern. When its on, there is alot of distortion
 
Difference between TB+L and TPL and TPR and TB+R is around 24V
 
R10L and R10R measures 220mv across
 
Changed a pair of tubes, no difference.
 
Where should i look into for the new problem?

 

[Jaivan]

So I've been using this amp for some time now and it's great, but I've always wondered what is it's max output using 12AU7's?
How would I go about measuring this this?

 

[egotrip]

Just recently found this awesome amp, and I want to give it a try.
I am new to head-fi, and want a good starter amp. I love the idea of a DIY project. So this is right up my alley.
I have read the entire thread, but have overlooked some crucial informasion by all the reading.
Do the kit from Glass Jar Audio come with a 110vac or 220vac transformer?
I have contacted Glass Jar Audio trough their website, but haven't recieved any answer yet unfortenatly.
 
Looked for the parts on the BOM, and not all of the parts are avaiable from one place, witch is a drawback, since I live over here in Norway, where this kind of parts is hard to find, and postal handling is slow. Therefore getting all the parts from one place, as a kit, so i know i got all the parts, and haven't overlooked some parts, would be great.  (sorry about the poor english, and some long sentences)

 

[capernicus]

Quote:

Just recently found this awesome amp, and I want to give it a try.
I am new to head-fi, and want a good starter amp. I love the idea of a DIY project. So this is right up my alley.
I have read the entire thread, but have overlooked some crucial informasion by all the reading.
Do the kit from Glass Jar Audio come with a 110vac or 220vac transformer?
I have contacted Glass Jar Audio trough their website, but haven't recieved any answer yet unfortenatly.
 
Looked for the parts on the BOM, and not all of the parts are avaiable from one place, witch is a drawback, since I live over here in Norway, where this kind of parts is hard to find, and postal handling is slow. Therefore getting all the parts from one place, as a kit, so i know i got all the parts, and haven't overlooked some parts, would be great.  (sorry about the poor english, and some long sentences)

You should be able to get the entire kit from Glass Jar Audio - aka Jeff Rossel - with everything you need to build the whole kit.  He will give you an excel order form will all of the kitted parts on it.  If you decide like I did to build your own enclosure or would like better caps or whatever then you can elect to leave some parts out or buy extras of parts as well.  I bought the kit from Glass Jar but due to my design I ended up having to get a few more parts to make it all work the way I wanted to.  Be patient and I'm sure Jeff will get back with you.  If not, e-mail him again.  Best of luck!

 

[egotrip]

Quote:

You should be able to get the entire kit from Glass Jar Audio - aka Jeff Rossel - with everything you need to build the whole kit.  He will give you an excel order form will all of the kitted parts on it.  If you decide like I did to build your own enclosure or would like better caps or whatever then you can elect to leave some parts out or buy extras of parts as well.  I bought the kit from Glass Jar but due to my design I ended up having to get a few more parts to make it all work the way I wanted to.  Be patient and I'm sure Jeff will get back with you.  If not, e-mail him again.  Best of luck!

I just recieved an e-mail from jeff. just as you described, an excel orderform, neatly arranged.
I also got an answer to my question of the transformer primary voltage.

 The Transformer is dual primary so it will work for either voltage.

My order will be placed in a near future

 

[jjazzyj]

So I've been using the SOHA II for a while now and I've noticed a problem creeping up. After about a year, when listening to the amp with increasing frequency I get a crackling noise in one channel (usually left channel) then the E12 kicks in. At first it seemed that it was due to me having the tube voltage set to 100v. I changed it back to 60v and it seemed that the problem went away, but now it is back. I've tested the amp and the only thing that is weird and has been weird since I built the amp is the difference between TB+R and TPR is 15V instead of 19V. TB+L and TBL measure 19V. The tail current is set correctly. I've tried a number of tubes as well. 6N2P, GE 5963, Sylvania 5963, Sylvania 5814A, CBS Hytron 5814A. I get the same problem with all.  I've already checked for shorts and cold solder joints and there's nothing obvious.
 
Anyone have any thoughts on where to start troubleshooting?
 

 

[Avro_Arrow]

If you mean by "kicks in" that the E12 is muting, then the relay contacts are bad.
If you mean it has un-muted then the problem is likely in the input circuit.
The E12 shorts out the input when it's muting and releases the short when un-muted.
The problem is not likely to be after the tube as it would be there weather the
circuit was muted or not...
 
Good Luck!

 

[jjazzyj]

What I mean by 'kicks in' is that I hear crackling and the E12 mutes. Then a few random seconds later it un-mutes, then some random time later more static/crackling and the E12 mutes again.
 
Quote:

If you mean by "kicks in" that the E12 is muting, then the relay contacts are bad.
If you mean it has un-muted then the problem is likely in the input circuit.
The E12 shorts out the input when it's muting and releases the short when un-muted.
The problem is not likely to be after the tube as it would be there weather the
circuit was muted or not...
 
Good Luck!

 

[Avro_Arrow]

In that case I would be looking at the output stage and servo.
The DC offset protection of the E12 is probably kicking in.
Can you monitor the output with voltmeter and see if you are
getting excess offset?

 

[jjazzyj]

I will once I have the chance. I'm guessing at this point that Q1, Q2 for the right channel will need to be replaced. This is based on prior conversations in this thread. My first step should be to resolve the voltage difference issue that I described earlier. Then go from there I think. What are you thoughts?
 
Quote:

In that case I would be looking at the output stage and servo.
The DC offset protection of the E12 is probably kicking in.
Can you monitor the output with voltmeter and see if you are
getting excess offset?

 

[egotrip]

I have finally ordered myself a Soha II kit.
Just waiting for Jeff to process the orderform, pack and ship it.
To bad International shipping is slow....

 

[egotrip]

Anyone knows the diam.. on the shaft of the alps pot (6,3mm)?
and where to find powerswitch to use, I am looking for a on/off rotary switch w/same shaft diam.
This for use with idetical knobs.

 

[regal]

Quote:

Anyone knows the diam.. on the shaft of the alps pot (6,3mm)?
and where to find powerswitch to use, I am looking for a on/off rotary switch w/same shaft diam.
This for use with idetical knobs.

6mm