[donunus]

Figured out how to get rid of the leftover hum. Unplug the laptop or the usb cable from laptop to dac. The hum has something to do with the laptops power interacting with the usb connection. Its creating some sort of interferance because it makes the stax hum even though the amp is not plugged in the wall

 

[Ricey20]

Yep. Try plugging in your laptop to a inverter in your car while the car is running, you will get hum and static that will blow your ears

 

[yale.reinstein]

Quote:

Originally Posted by donunus /img/forum/go_quote.gif I noticed that my stax 252 has a hum that i can hear on the 202s even though the unit is unplugged. If I hold the 252s casing with my hands, the hum goes away. Is there any way I can permanently get rid of this hum?

Yes, ground it or just wait. I had the same issue with my 252A and my Lambda Pros with a non-stax selected power supply - which I assumed was the culprit. Grounding it became a real hassle and strangely enough one night they no longer hummed!

Also - for low level listening will I notice a difference with what I have if I upgrade to a nicer amp unit? I realize the 252 really doesn't have the juice for anything thumpy and loud - but I usually listen laying down in a silent room. Anyone have any suggestions for me? T1 or just hold out as long as possible and go for broke with something nicer? Another problem I have is the fact that I don't like the wideness and limited outputs of the current headamp KGSS or the look of tubes.

 

[donunus]

wait? hehehe What? it just goes away? maybe you didnt notice but something in your room was causing the hum and it went away when that appliance was no longer used. My transformer was supplied by audiocubes for the stax specifically by the way.

 

[bralk]

Quote:

Originally Posted by donunus /img/forum/go_quote.gif Figured out how to get rid of the leftover hum. Unplug the laptop or the usb cable from laptop to dac. The hum has something to do with the laptops power interacting with the usb connection. Its creating some sort of interferance because it makes the stax hum even though the amp is not plugged in the wall

I had the same problem with a srm-323/sr-303 and it got very loud if I touched the laptop (macbook Pro). It was also impossible to use wireless microphones when the laptop was running.
I now use an old Macbook G4 for music and the problem has gone away.

cheers

Tom

 

[oofie810]

I have the same problem with my 252A. Temporary solution for me was to connect it to my LD mkIII using rca cables. Now my problem now is that I want to sell my litte dot.

 

[plaidplatypus]

Quote:

Originally Posted by yale.reinstein /img/forum/go_quote.gif Yes, ground it or just wait. I had the same issue with my 252A and my Lambda Pros with a non-stax selected power supply - which I assumed was the culprit. Grounding it became a real hassle and strangely enough one night they no longer hummed! Also - for low level listening will I notice a difference with what I have if I upgrade to a nicer amp unit? I realize the 252 really doesn't have the juice for anything thumpy and loud - but I usually listen laying down in a silent room. Anyone have any suggestions for me? T1 or just hold out as long as possible and go for broke with something nicer? Another problem I have is the fact that I don't like the wideness and limited outputs of the current headamp KGSS or the look of tubes.

Justin could add more outputs to your KGSS. I had mine made with 2 pro bias and 1 normal bias output. For the Lambda Pro I would suggest the Woo GES it's a much better sonic match than the KGSS.

 

[ericj]

Quote:

Originally Posted by donunus /img/forum/go_quote.gif Figured out how to get rid of the leftover hum. Unplug the laptop or the usb cable from laptop to dac. The hum has something to do with the laptops power interacting with the usb connection. Its creating some sort of interferance because it makes the stax hum even though the amp is not plugged in the wall

It sounds like this could be a ground loop. What frequency is the hum? If it's 2x your mains frequency (I don't know if your power out there is 60 cycle like north america or 50 cycle), then it's probably a ground loop.

Transformer-coupling the audio would probably help, but might color the sound as well.

At least I'm assuming here that you're using a usb dac rather than a usb spdif interface connected to another dac. IMHO it's easier to transformer-couple spdif than analog without making any negative impact.

 

[donunus]

the hum is 50 or 60 hz not double

 

[krmathis]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif A sentiment i've heard before - that whatever a transformer box may lack in micro-detail and extreme spectral extension, they make up for in dynamic range.

Yeah, it seems to be the general consensus.
I have never heard a really powerful direct-driven amplifier like the KGBH, or a larger transformer than the SRD-7 Pro, so its not the final word. It can be a pointer in the right direction though.

 

[Kraps]

Will SRM 727II be able to drive two O2's at a time (since it has two outputs)?

 

[2deadeyes]

Not sure but from using the 717, it was able to drive 2 O2s, MK1 and MK2, with no problems. I would assume the 727 shouldn't have any problems.

 

[minivan]

has any1 brought up this interview of head of stax and technical director of stax before?
it talk about:
stax's business operation, number of staff, manufacturing process, the originality of the making of 007a and comparison of 007 vs 007a, reason why they change the voltage bias from 230v to 580 v. about they will be releasing a model price in between 007a and 404, releasing a 001mk2 for better portability, discussion of solid state vs tube amp

 

[Oublie]

have you the original links minivan or a text version of this info

tks

 

[dvse]

Quote:

Originally Posted by minivan /img/forum/go_quote.gif has any1 brought up this interview of head of stax and technical director of stax before? it talk about: stax's business operation, number of staff, manufacturing process, the originality of the making of 007a and comparison of 007 vs 007a, reason why they change the voltage bias from 230v to 580 v. about they will be releasing a model price in between 007a and 404, releasing a 001mk2 for better portability, discussion of solid state vs tube amp

It would be awesome if you could translate some of the more interesting excerpts from it (eg. 007 vs 007a)!