or Connect
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › SOHA II Builders Thread
New Posts  All Forums:Forum Nav:

SOHA II Builders Thread - Page 98

post #1456 of 1686

 

Quote:
  

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.

 

Have you searched the usual sources... like RS components, Reichelt, Conrad (all in Germany)?

Don't know about shipping to Norway, but it should be cheaper than ordering from the US for a small

number of parts.

 

I'm getting most of my stuff from RS Components ...

post #1457 of 1686

i am not sure of what i should search for.

I was thinking of cutting the power for ether the 220 before the torodal, or the ground after the torodal and having a main powerswitch in the back.

 

any ideas of witch would be best?

post #1458 of 1686

Always switch power on and off before the transformer... there are nice IEC power inlet modules

like this one ->  http://de.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=3521819

 

post #1459 of 1686

edit


Edited by egotrip - 10/28/10 at 4:32am
post #1460 of 1686

Waiting for my kit to be shipped from Glass jar Audio.

I am looking forward to build this amp.

post #1461 of 1686

Still waiting for my kit to be ready for shipping.

3.rd week of waiting. And no answers from Jeff.

Guess he is really backed up.

post #1462 of 1686

Waiting for my kit. Jeff shipped it today. :D

post #1463 of 1686

Hey everyone,

 

First I want to say thank you to runeight for the hard work designing this amp and glassjar for the kit! I just got the amp working yesterday and it sounds great!

 

Unfortunately, I do have an issue though. I am getting an annoying sound when the amp is on and I turn the volume knob or tap the tubes, or even move my hand across the desk that the amp is sitting on! Otherwise, the amp is very silent until I move lol, and its a little bit annoying which is unfortunate. I did some searching and while I couldn't find much useful, I think the term I'm describing is that the tubes are very "mircophonic." This is the standard kit from glassjar, same tubes 12au7, one says Bechman on it and the other RCA electron. When I remove the tubes and turn the amp on, I cannot hear this effect, but I do not know if that means anything. As far as a "hum" or "hiss" noise, the amp only does that very faintly at max volume (with the tubes in again) but that is being really nitpicky as I'll never get anywhere close to that volume with the headphones I have now with music playing, and even then its barely audible. This "microphonic" effect however is loud, and its a bit worse in the left channel.

 

Did I screw something up? Or is this a characteristic of the tubes? Thanks all!

post #1464 of 1686

Do you have it cased up?  A lot of times these noises go away once it is.

post #1465 of 1686

That's a good point, no its not cased up yet. It's sitting in the standard hammond case with the top and back plate removed. I just wanted to get it fired up and worry about nice case work later :) 

 

If it was a more subtle noise or one that changes with volume I'd suspect that it would be some ground issue or casing issue, but this is so prominent that I don't think thats it (but what do I know lol I'm very much a beginner!).

 

It would be nice if it would go away over time! Wait and see I guess. Also if I had to pinpoint the tubes I'd say the Beckman one would be the trouble maker because it was in the left slot. The sound comes through both channel but is louder in the left, and tapping the right and left tubes it seems like the left one rings more if that makes sense lol. 

post #1466 of 1686
Quote:
Originally Posted by viking87 View Post

That's a good point, no its not cased up yet. It's sitting in the standard hammond case with the top and back plate removed. I just wanted to get it fired up and worry about nice case work later :) 

 

If it was a more subtle noise or one that changes with volume I'd suspect that it would be some ground issue or casing issue, but this is so prominent that I don't think thats it (but what do I know lol I'm very much a beginner!).

 

It would be nice if it would go away over time! Wait and see I guess. Also if I had to pinpoint the tubes I'd say the Beckman one would be the trouble maker because it was in the left slot. The sound comes through both channel but is louder in the left, and tapping the right and left tubes it seems like the left one rings more if that makes sense lol. 



Some pictures may help.  It could be your wiring acting like an antennae.  It's hard to say.  Mine doesn't make noises when it's open, at least not to that degree.  One thing that does help is to make sure your chassis is grounded.  Coincidentally, my SOHA II proto is acting up (hiss on right channel and e12 firing off) and I have the top off on my desk and I'm in the middle of probing.  The sad part is I forgot what I'm looking at (part location) as the proto is a bit different than the final.

post #1467 of 1686

Thanks Holland. I'll try to put up some pictures up tonight when I get home. Though my wiring isn't pretty right now, I have a hard time believeing that's the source. If its acting like an antenna, wouldn't turning up the pot increase the noise? Also wouldn't it be kind of constant? The noise I am hearing is more like a physical noise amplified through the headphones. What I mean by that is when I touch the pot or move the pot to its stop I can hear it hit the stop. I can hear the tapping of the tubes through the headphone. This is why I really think its the tubes because they are the only things that I think can somehow turn these vibrations into an electrical signal that goes to my headphones? Again when I sit very still and don't change the volume, the amp is very nicely quiet lol.

 

Hopefully I've done a decent job explaining what I hear, my guesses as to why are just that - guesses. I really don't know much about the inner workings of this or any amp! lol


Edited by viking87 - 11/22/10 at 1:39pm
post #1468 of 1686


 

Quote:
Originally Posted by viking87 View Post

Thanks Holland. I'll try to put up some pictures up tonight when I get home. Though my wiring isn't pretty right now, I have a hard time believeing that's the source. If its acting like an antenna, wouldn't turning up the pot increase the noise? Also wouldn't it be kind of constant? The noise I am hearing is more like a physical noise amplified through the headphones. What I mean by that is when I touch the pot or move the pot to its stop I can hear it hit the stop. I can hear the tapping of the tubes through the headphone. This is why I really think its the tubes because they are the only things that I think can somehow turn these vibrations into an electrical signal that goes to my headphones? Again when I sit very still and don't change the volume, the amp is very nicely quiet lol.

 

Hopefully I've done a decent job explaining what I hear, my guesses as to why are just that - guesses. I really don't know much about the inner workings of this or any amp! lol


Oh, that type of noise!  Noise from poor wiring can be affected by the pot or not.  It depends which section is being impacted.  I thought when you said you move your hands around you pick up noise, that could be wiring issues.  When I was a kid, I built a digital counter, a millisecond timer, and the wiring was bad.  When I waved my hand over the circuit, the clock jumped around.  Thus I rebuilt it with tight wiring, laid flat, and twisted if necessary.  It was just a breadboard experiment, but I learned alot from that.  Decades later, it still sticks with me.

 

Your type of noise may be helped by using "those pointy feet" thingies.  I am drawing a blank on the name right now.  Different tubes may help too.  I have a stepped attenuator on mine and when I click it, I hear it, but it's not horrible.  I also have "those pointy feet" thingies due to microphonics and also the need to vent underneath.

post #1469 of 1686

Lol, I don't know what you mean by those "pointy feet thingies" but I'm sure its the tubes that are the problem. Or tube I should say. I just got home to play around with it and I switched the tubes from Left to Right, and now the sound is primarily in the right channel. It is quite annoying so I am buying a new set of tubes, although I think the RCA one is fine, its the Beckman that is the real trouble maker. If there is something else I am doing wrong, please let me know but I think it's just this funky tube!

 

Thanks for your help holland!

 

On another note, any tube recommendations? I know there is a separate thread and I should just try them out on my own but if your willing to throw me a recommendation I'll gladly accept! lol. I'm getting started earlier on the whole tube rolling thing than I had planned. :) Bass seems a little recessed, but the highs seem to sparkle with what I have now. My description of audio sounds are pretty bad lol, I just like good music!

post #1470 of 1686
Quote:
Originally Posted by viking87 View Post

Lol, I don't know what you mean by those "pointy feet thingies" but I'm sure its the tubes that are the problem. Or tube I should say. I just got home to play around with it and I switched the tubes from Left to Right, and now the sound is primarily in the right channel. It is quite annoying so I am buying a new set of tubes, although I think the RCA one is fine, its the Beckman that is the real trouble maker. If there is something else I am doing wrong, please let me know but I think it's just this funky tube!

 

Thanks for your help holland!

 

On another note, any tube recommendations? I know there is a separate thread and I should just try them out on my own but if your willing to throw me a recommendation I'll gladly accept! lol. I'm getting started earlier on the whole tube rolling thing than I had planned. :) Bass seems a little recessed, but the highs seem to sparkle with what I have now. My description of audio sounds are pretty bad lol, I just like good music!



You're very welcome.  It's been a long time since I've been on these forums, over a year I think.  It's good to see these projects still rolling.

 

"pointy feet thingies", lol.  They are just spiked feet for amps and such.  I can't remember where I got mine.  It's been over 2 years since I built this amp!

 

I am using the Tungsram ECC82.  I like it very much.  It's a bit different than the more common 12AU7s.  I also very much like the Amperex 8416 tubes.

New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › SOHA II Builders Thread