My X600 hum for a while

[ljames]

Wow, never know there is a a section for Pass Labs alone! Great.

I have a pair of X600 for several year now, yeah, the oldest one I guess, make great sound driving my old trustful B&W 802.

However, it always has one problem in one of X600 blocks. It hums for like 20-30 minutes when I turn it on, the other one is fine, no any noise. The hum coming from the unit, not from speaker, not sure where it comes from. (transformer is suspected though) It will become completely silent after that period, seems warming up has fixed or stabilized something. Any idea how I may fix this?

 

[sakellogg]

cant fix it, sorry. gunna have to send it to zen mod for proper disposal.

im kidding.
have you tried it with nothing hooked up to it?
like just the amp to speakers.

 

[Zen Mod]

cant fix it, sorry. gunna have to send it to zen mod for proper disposal.

im kidding.
have you tried it with nothing hooked up to it?
like just the amp to speakers.

no kidding in that idea - it's completely sane



good advice - disconnecting speakers and source ( preamp)

if humming is still there - it's certainly xformer

if humming amp share same mains outlet with non-humming amp , influence of DC in mains can be discarded ... so - only cure is to replace mains xformer

b'cause monoblocks are in case , replacing xformers ( by orig. specs) in both is probably more practical than chasing original one for just one amp .

or - removing hummster from amp , de-nuding it and give him a bath in any sort of nitro based varnish or paint .

I will try that first .
cheapest and most DIY solution.

edit : in any case - least time consuming solution is to send both lousy amps to me , for quick check , and proper disposal after that

I'll not charge anything for that ........ sole reason is love to DIY folks

 

[AudioSan]

no kidding in that idea - it's completely sane



good advice - disconnecting speakers and source ( preamp)

if humming is still there - it's certainly xformer

if humming amp share same mains outlet with non-humming amp , influence of DC in mains can be discarded ... so - only cure is to replace mains xformer

b'cause monoblocks are in case , replacing xformers ( by orig. specs) in both is probably more practical than chasing original one for just one amp .

or - removing hummster from amp , de-nuding it and give him a bath in any sort of nitro based varnish or paint .

I will try that first .
cheapest and most DIY solution.

edit : in any case - least time consuming solution is to send both lousy amps to me , for quick check , and proper disposal after that

I'll not charge anything for that ........ sole reason is love to DIY folks

and then you send the chassis to me? for free ofcourse

 

[Zen Mod]

naah

ya remember Christine's disposal ?

 

[AudioSan]

hehehe

 

[ljames]

Thank you guys for the good advise and fast replies. I will try it tomorrow when it's cold. Now it's warm, and when hot/warm states, there is no buzz at all.

And thank you Zen Mod for the offering, it's going to be a big pain shipping these monsters at over 300lb.

 

[sakellogg]

i have had realy good luck making torid xformers dead quiet by getting them nude, and wrapping with super33, then 1or2 wrap of rubber isolation tape. if you need transformer paint let me know. i have gallons of the good stuff. ill send u some in a can if u pay the shipping.

 

[a.wayne]

i have had realy good luck making torid xformers dead quiet by getting them nude, and wrapping with super33, then 1or2 wrap of rubber isolation tape. if you need transformer paint let me know. i have gallons of the good stuff. ill send u some in a can if u pay the shipping.

Hello,

Could you elaborate on this , what if just wrapped in rubbertape...?

 

[sakellogg]

just wraping in rubber tape is what i do when i unwind or rewind xformers. and it has worked well for me. i use the super33 (eletrical tape) as the first wrap to hold it together then i use the rubber tape.
you could just wrap them in rubber tape. in this case i would make sure that they are clean, and no shorts....etc first then do it.
i guess im saying.....dont use this as a band-aid on a bad xformer. but any hum within reason on good xformers gose away when i do this.

 

[sakellogg]

forgot to say....... on torids, never done this on others.
and keep in mind heat. it will keep them warmer than normal.

 

[BlownRx7]

sakellog,
What is rubber tape?
Where do you get it?
TIA

 

[sakellogg]

scotch linerless rubber splicing tape
130C
for low and high voltage (thru 69kV)
can be used on cables whose emergency overload temp can reach 130deg C.
right off the box. comes in 2" 1" and i think 1/2" width by 30'.
as far as where..... proably a electrical supply house. i get it at work from ralroad projects that they dont use it on but send it to us anyway.
the skinner the better.

 

[sakellogg]

i didnt answer what is...
its a soft rubber, used for all kinds of stuff. ive seen it used for wrapping the splices at the weatherhead of a main service of homes. sealing outdoor ant. conectors for r.f.
its like 2mm thick elec. tape that has no glue on the back that will seal itself.
if you take a strip of it and roll it into a ball on your desk it will become a ball of rubber. but its not sticky. i love it works good for wite ties too.

 

[ljames]

It's not happening lately, until today, I hear it again. I guess it's much related to the room temperature when I power it on.

I realized one thing, the one that buzz, the meter is lower, it's much less than 1/4 of full range while the other one is very close to 1/4. Is it possible to adjust the meter (I guess it's bias?)

And, we have 220V power supply at home, I wonder if the power is also something I may try, wonder if there is way to change it from 110V to 220V easily (internal switch or minimum re-wirling).

Lastly, does X600 got service manual?

Again, thanks to all who replied with great suggestions.