who makes the best volume pots / stepped attenuators?

Probably more of a DIY question, but I think it belongs in the hi-fi section, given how overlooked this important function seems to be...

I've heard Vishay stepped attenuators are very good for the money, as are ALPS Blue, but do the aforesaid companies (or anyone else for that matter) make higher quality steppies & pots for use in more expensive pre-amps?

Why are ALPS Blue pots so ubiquitous? See them in everything from £200 Ming-Da's to £3000 Arcam's....

Can anyone give me some ideas/examples of sub £2k pre-amps with super-duper pots/steppers (passive pre's included)?

Rgds
DT

 

IIRC Alps do make a super-dooper one but it is REALLY expensive. It is black I think.

If you want something much better, you really need to look at transformers I think...

As someone recently pointed out to me, if you have an amp with negative feedback you can re-wire the feedback loop so the pot becomes one of the resistors and thus you can adjust the volume but adjusting the amount of feedback. This cuts out a lot of the problems with the normal way of doing things.

 

No it does not - it means the amps bandwidth, noise and distortion performance (and for some topologies, stability too) will vary hugely depending on the pot setting. Not recommended.

PS. early DPA kit used Penny & Giles pots - very nice!

 

Perhaps I misunderstood what was said to me then. It was definitely to do with using it in part of the feedback loop. I can find the email when I get back home if you like.

 

Oh yes, what you proposed works OK, but only for varying gain over a very narrow window - not useful for the range of attenuation required in hifi volume control. Certainly interested in the email though.

 

Its quite often done that way but it does introduce problems. Think about the noise floor as well.

 

The best analogue volume control I know of, in terms of measured noise, linearity, balance, etc is on the left side of this picture:

 

I take it that's the NAD silverline pre?

 

No, it's the Master Series integrated (M3).

 

Hi,

Depending on what you want to spend. Have a look at the following. I have used these to good effect.

http://www.dact.com/html/attenuators.html

Also the Alps blue pots can be had for little money. If you buy in bulk and from the right supplier, they cost very little. Ideal for the mass production and keeping costs down.

On the Hifi Collective site, are a number of options. The Panasonic pots are very good as well. But have a look at the Dale Vishay stepped attenuator as it is a good one.

http://www.hificollective.co.uk/components/potentiometers.html

Transformer volume controls are well worth a look. Can be a pain to put into an existing amp but you can get build a pre with them in. Or buy one. Here are two.

http://www.diyhifisupply.com/diyhs_django.htm

http://www.bentaudio.com/index2.html

Audio Synthesis do a very good passive using vishay resistors.

http://www.audiosynthesis.co.uk/passion_ultimate.htm

SCIDB

 

Hi,

Music First Audio Passive Magnetic Preamp (abreviated PMP - pronounce as Pemp for fun) @ £ 1,500.

BTW, NON of the currently commercially availabe switched attenuators are particulary good, simply because theya re all based on the arguably more economic and cheaper solution of using a sngle deck switch and daisychaining loads of resistors, rather tha using two decks and a pair of resistors per position (shunt attenuators are usually best avoided, for obvious resons).

The best traditional attenuators I have made used GEC Pleesy NOS Type 72 Switches (currently still made by Blore Edwards but VERY expensive) and the dual resistor per position principle, using old Holco resistors and using a technique called "wire wrapping" where the actual contact and mechanical strength comes from wraping the wire (in our case the leadout from the resistor) around a stud (part of the single piece solid silver contact on those type 72 switches). Solder is only used to seal/fix the connection.

These where better than than an all Vishay Audio Synthesis Passion (a shunt pot) and DACT's and anything else we tried, untill we hit the first transformer attenuator, that is.

Ciao T

 

Any details for the GEC?

What did you think of VFV? The vibe put me off to be honest.

 

Bent Audio TAP

I've just noticed that Bent Audio have a new remote controlled preamp that looks gorgeous:



Thorsten, why is Colin using S&B TXs without cans?

 

Yep, saw that new Bent Audio (very, very bad name for a company!) pre the other day. Looks pretty interesting. Fully loaded and with remote control too! God bless 'em!

BTW - those Seiden steppers look pretty nice!

DT

 

DT I use the Dale/Vishay one in the link on SCIDB's site. It replaced an Alps blue pot, and sounds much better. Despite being of equal value to the Alps pot it 'sounded' a lot louder.

Thorstens comments that non of the commercially available stepped attenuators are very good. Cobblers IMHO.

 

Well, my Pathos uses a Vishay stepper, and I'm very impressed with its performance (and the quietness/balance of the pre section, given that its tube based).

Just wanted to know what quality of pot/stepper we should expect at different price levels, and its interesting that so many suggestions have come up! Wasn't aware there were so many alternatives to the ubiquitous ALPS unit

DT

Thorsten just stepped in with his comments/suggestions and that's fine. I'm aware of his commercial activities and any potential bias that may (or may not) engender. AFAIK he is a "purist" audio engineer, and I fully expect him to be critical of anything less-than-perfect.

 

I quite fancy the new audionote one on hificollective. Nick (of hifi coll) knows peter Q of Audionote, so I dont imagine seeing these things elsewhere. It would be cool to have the same vol control as a top audionote pre. I think mine is '50' and they only do '100' so I'm cream crackered (not that I want to change anyway..but..)

 

Those AN pots do look quite interesting - cheaper than I thought they would be! Aren't AN pre's £10k+??

DT

 

Hi,

Used to be sold at ham ralleys/vintage audio fairs by one of the smaller valve/parts vendors at around 25 quid the piece, long out of stock, new manufacture blore edwards last time I looked where around 270 quid, in the late 90's.

Here is a piccie of one of the first attenuators I build using these switches....



This one used a particular type of resistor Maplin carried a while back (again, long lost), which surprisingly where nonmagnetic and sounded very good.

And no, please do not ask why one switch is back to front.....

Sorry, I'm not tracking, somehow....

Ciao T

 

Hi,

Not sure who Colin is (Bent Audio is John Chapman). The why? Maybe to fit the low profile.

I prefer the cans, for limiting the hum pickup if suitable souces are nearby.

Ciao T