andre tchmil

need some 20 pieces of ECC81  ,
what are the good sources and brands in europe , at fair prices.


chefducuisine

Contact these guys:
http://www.tubeampdoctor.com/en/shop_Other_brands_OEM_Tubes_Preamp_doubletriodes/

Best way is to give them a ring and let them know what you need and for what purpose. They will come up with a recommendation.


gyraf

Or Billington in the UK.

You're restoring K&H UE100's?

Jakob E.
..note to self: don't let Harman run your company..

andre tchmil

Or Billington in the UK.

You're restoring K&H UE100's?

Jakob E.

 ;) yes.
Any advice on brands ?

andre tchmil

I see many exotic branded tubes , some claiming to be military labeled Mullards,
others rebranded Ei.
Prices for unknown brands  go from 8 to 35 euro.
I'm lost. :o

gyraf

The UE100 seems to be VERY forgiving when it comes to tube types. I would just get some halfway-decent types (maybe EI?), check that they actually work, put them in, and forget about it...

Also, if you're restoring, it's far from unthinkable that most original tubes are still within specs..

Jakob E.
..note to self: don't let Harman run your company..

andre tchmil

The UE100 seems to be VERY forgiving when it comes to tube types. I would just get some halfway-decent types (maybe EI?), check that they actually work, put them in, and forget about it...

Also, if you're restoring, it's far from unthinkable that most original tubes are still within specs..

Jakob E.

true , I measured them and 80% of them are still within specs, but now the whole unit is disassembled it's better to do it  now.
I know it's a bit of an overkill.
The hardest thing is cleaning those switches. Still looking for a good procedure.
« Last Edit: December 29, 2016, 07:55:58 AM by andre tchmil »

gyraf

PLEASE post your findings, methods and procedures...

I'll have to go down that route sometime in the not too distant future (if I can get my local ME to let go of them for a while).

Jakob E.
..note to self: don't let Harman run your company..

andre tchmil

I have good results cleaning the switches with kontakt 60 and isopropyl in that order.
Replaced  " all"  electrolytics .
The only thing that bothers me are the  loud  thumps when switching from linear ( bypass) to active.
A design flaw , or should I look somewhere at the gain stage ?


PRR

Measure the DC Volts at the switch, both ways. You probably have a leaky coupling cap.


andre tchmil

Measure the DC Volts at the switch, both ways. You probably have a leaky coupling cap.


I isolated module A.  low shelf.
Didn't measure anything suspicious.
The thump is there when switching from 6 to12dB/octave at a fairly high boost.
I think it's inherent to the design , no ?
« Last Edit: January 11, 2017, 10:41:55 AM by andre tchmil »