[Tjj226 Angel]

  Fellow Stax mafiosos,
 
I need your help. Yesterday I noticed, for the first time, a very, very low humming noise coming from my modified T1. This starts as soon as I hit the pre-heat button and without any source feeding the amp. To make things clear: the noise comes from the amp and is audible when sitting next to it (1-2 ft)!
 
This is very odd, what could be the cause of this problem?
 
Thanks in advance for any help...
 
Edit: it's a slight, not easily audible noise. I still cannot tell with certainity from where it comes exactly, but it's definitely the amp itself. It doesn't seem to effect sound quality when I listen with my Lambda Signatures.

 
 
Could be that one of your tubes is going bad. 

 

[Tjj226 Angel]

I will be joining you guys next week with some stax lambda nova classics. 

 

[AManAnd88Keys]

   
 
Could be that one of your tubes is going bad.

Wouldn't that have an effect on sound quality? I once experienced a bad tube on a headphone amp for dynamics, which had a huge impact on what came out of the headphones.

 

[edstrelow]

Well I am not buying what he is trying to sell here. I am thinking he is something like an internet troll. I think he should go to a hearing doctor and get his ears checked for tinnitus and come back with a doctors note before he posts again.

I tend to agree.  I pay little or no attention to posts from people who don't list equipment in their profile.  You have no idea where they are coming from. and mostly it seems to be from nowhere.

 

[AManAnd88Keys]

Problem solved: it was the placement of the amp! Looks like the T1 vibrates ever so slightly when it's switched on. I put it on a place where the rubber feet on the back (where the trafo is) have contact with a spot on the desk that allows for this low pitched hum. When I switch on the amp and slightly lift it up so that those feet have no contact, the noise is gone.
In a way the vibrations of the amp on that particular spot caused the amp to turn my desk into a sort of subwoofer

 

[jaycalgary]

Could a amp like the BHSE be scaled back so it is half the power and less parts? Maybe the 009's would shine on a really refined amp without all the headroom needed for the 007's.

 

[paradoxper]

Could a amp like the BHSE be scaled back so it is half the power and less parts? Maybe the 009's would shine on a really refined amp without all the headroom needed for the 007's.

Isn't that just a KGST?

 

[Tjj226 Angel]

  Wouldn't that have an effect on sound quality? I once experienced a bad tube on a headphone amp for dynamics, which had a huge impact on what came out of the headphones.

 
I am not quite sure. I had some cheap JJ tubes that started whining and then progressively got worse and then the sound quality started to go down hill and finally it started to red plate. 
 
I see you got it fixed with rubber feet though.

 

[s1rrah]

Had no idea Stax made a DAC; the X2t ... check this crazy thing (anybody heard one?) : 
 
...
 

 
...
 
http://app.audiogon.com/listings/da-converters-stax-x2t-2013-11-29-digital-ha4-7rx
 
...

 

[DefQon]

Theres also the less expensive Talent Dac. I've only seen 2 of those for sale for alot of money on canuckaudiomart years ago.

 

[Tjj226 Angel]

The problem is that for that price you can also get a very nice audionote dac and crush that dac.

 

[jaycalgary]

The Stax dac looks like a work of art but it's older than the hills for a dac. Would it even sound as good as a Nad M51 that I use?

 

[Waltzingbeear]

Well I've read many different things on this thread (only what, 3000 messages or so??)
 
So I finally have the opportunity to give a little back.
 
I decided a little bit ago to finally buy a direct amp for my Stax headphones (that I've had since 1972). So I bought a SRM MkII/Pro. Got it and all seemed well, recapped it (not a fan of dried out old soggy caps) and put it back together, all fine. Except I could never get a nice quiet connection, too much line noise.
 
Was thinking about making the input differential, simple task on those units. Perused the schematics (which I found through this thread) and thought OK. doable. So this eve I opened it up to start the process. Who ever "designed" the grounding scheme for these things screwed up bad. Moved two wires, re-soldered them to the proper place, and now with the same hookup that wouldn't give me quiet audio before, it is absolutely quiet. I guess I get around to balancing it, maybe, someday.
 
To change it to proper grounding, cut the brown and black wires from the shell of the RCA input connectors and run it directly to the wire to the chassis next to them. Remove the remaining wire that runs to the pot, THATS IT.
 
With the as shipped wiring, it runs any ground current "past" the pot and it gets incorporated into the signal, wrong, This was a classic pin 1 problem.
 
Cheers
Alan
Waltzing Bear Audio

 

[davidsh]

What is a fair price for a sigma normal bias? Assuming it is in decent condition that is..

 

[DefQon]

$450-600. Sigma Pro's fetch little higher.