Wm goes Thermionic

Which have their own foibles - I looked at the mfaudio type approach for my volco. High quality stepped attenutor is one fine solution. But expensive to get right.
 
Dev said:
I think you mean a Naimee in denial:D

Sorry WM, I'm having a bad day.
Click to expand...

Dev,

Thats a bit below the belt :p I don't have a mechanical contrived & thin sound sir. New drivers any one :D
Try Wembley speakers Dev, very good.
Mind you Kashmir isn't sounding too shabby at present, prehaps a run in in time for the valves :)
 
so what would you call a good stepped attenutor, how much would it cost and would it fit into the space available in the minimax? i always thought the volume pot was likely to be a week point....
 
Well I am using a 24 way balanced stepped attenutor with 96 welwyn resistors. Cost is about £150. Its a very high quality switch - much better than the dact used in the vibe. I am looking at using vishays which would add £400 to the cost! Obviously price will be lower for unbalanced.

The unit is quite small - how much space do you have? Should I find out some more about which switch is used?
 
Why not try a shunt? All you need is 2 very good quality resistors, and an accurate pot and your are away. No point spending £££ on 96 welwyn when 2 vishay will do!

Mind you haven't tried the fake law, maybe a trip to Maplin tomorrow.
 
BBV

In that case, you really should try the shunt tweak.
It puts only 2 resistors in circuit, the pot just acts as a divider to ground. Therefore the only quality components you need to worry about are 2 resistors of your choice.
 
i could have sworn i saw an article in a hi-fi world where they had bought a stepped attenuator from i think taiwan... that had vishay resistors for only about 30 quid... i'll see if i can dig it out. having said that i seem to recall the unit looked relatively bulky.
 
Hi,

blakeaudio said:
so what would you call a good stepped attenutor, how much would it cost and would it fit into the space available in the minimax? i always thought the volume pot was likely to be a week point....
Click to expand...

First, the best I ever build is not really significantly better than a Vishay P11 linear track pot with a lawfaking resistor and only slightly so compared to a generic linear track carbon pot. BTW, the difference between linear pot lawfaked and log/audiotaper types even of the exactly same series is not small...

Secondly, the switch I used for that was a NOS surplus GEC Plessy type 72, currenty retailing as non-surplus in the £170+VAT range, it is characterised by using solid silver stud contacts with all other contact parts silver (solid) too.

Thirdly, the resistors where some of least coloured sounding ones available, based on bypass-testing (they are no longer available, so I'll save the brand).

Fourth, the attenuator was a "true ladder" type with only 3 resistors per position, constant input impedance type, directly hardwired without PCB.

Next to that DACT sounded broken and only an all vishay passion manged to pull level.

The original Sowter attenuator transformer (which is miles worse than S&B TX-102) pi$$ed over the lot in any meaningful way.

Ciao T
 
Mmmm, heard one of those Sowters, and compared to a DACT it sounded so s l o w, that if we were listening to vinyl, I'd have said it was running at 30rpm.
 
Markus arn't you in London this week?
The combo is sounding very coherent & Musical this morning, things are settling into place now. Very pleasing :)
 
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Hi Big Tone,

Out of interest, what other valve pres did you try?

The Minimax is an interesting pre but doesn't have much spare to work on.

SCIDB
 

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