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Alps potentiometer

R

RoA

pfm Member
Unlike others, I never had a problem with amplifiers using conventional volume parts such as an Alps but I do wonder if they have a place in expensive amplifiers these days.

None of the amps I currently have use It (coincidence rather than deliberately choice) but I noticed in a recent thread about the Rega Osiris that this £7500 product uses a $20 pot.

Maybe I got this wrong but there are better ways no?
 
I don't really understand the technical details but the limited range on some pots when using modern sources is very annoying. My old amps remote volume control was very difficult to use. Small changes were virtually impossible. Knob was never above 9 O'clock.

My current amp uses a pair of TI PGA2311UA's https://www.ti.com/store/ti/en/p/product/?p=PGA2311UA. Massive variable range on the volume. It's a joy to use.
 
I've never really thought the Alps Blue are that good from a sound quality pov, though my pre amp uses one as its motorised.

I remember years ago replacing one with a Sfernice P11 cermet pot from Russ Andrews (Richard Dunn also used them in his amps for a while) and the Alps sounded dull and bloated in comparison.

The cheapo Omeg conductive plastic pots sound just as good as the Alps, but the channel matching at low levels is shite.... i've never had an issue with the Alps in this regard.

The Panasonic pots were pretty good iirc.

Anyone tried the motorised TKD pot.?
 
S-Man, I would have to ask our design and / or service teams but I have heard no reports "from the field" of any channel imbalance issues, and although there are apocryphal stories of non linearity at very low levels I, again, have not encountered any either.
 
quickie said:
I've never really thought the Alps Blue are that good from a sound quality pov, though my pre amp uses one as its motorised.

I remember years ago replacing one with a Sfernice P11 cermet pot from Russ Andrews (Richard Dunn also used them in his amps for a while) and the Alps sounded dull and bloated in comparison.

The cheapo Omeg conductive plastic pots sound just as good as the Alps, but the channel matching at low levels is shite.... i've never had an issue with the Alps in this regard.

The Panasonic pots were pretty good iirc.

Anyone tried the motorised TKD pot.?
Click to expand...


I use digital attenuation nowadays, but always liked the Alps Blue soundwise.
The fabled Panasonic is maybe a bit better - that was the last pot I used and still have it.
Sfernice (bought by Vishay) P11 is too clinical and bright for me - I still have a couple. Flaky build quality.
I haven't tried Omeg or TKD. I have tried a couple of resistors set at my usual listening volume as a comparison to the Alps. Not much in it!

For the DIY'er channel imbalance can be fixed with a couple of "faking" resistors. IIRC I achieved <0.5dB matching for a cheap chinese pot recently for the bass control in an active crossover.
It's very labour intensive though!
 
Mynamemynaim said:
assuming the error is constant across the usable range...
Though of course you should be able to improve the results
Click to expand...

No, surprisingly I was able to fix it over the whole range (on my sample size of one!). I had to "offset" the lower end with a series resistor and "curve fit" the rest with a parallel resistor.
 
RoA, I believe that many and various pots were tried and listened to and their consistency and long term durability and reliability assessed and given the long history of previous Rega products using Alps pots and the negligible rejection rates it was decided that on the balance of positives they were the one to be used.
 
paul darwin said:
RoA, I believe that many and various pots were tried and listened to and their consistency and long term durability and reliability assessed and given the long history of previous Rega products using Alps pots and the negligible rejection rates it was decided that on the balance of positives they were the one to be used.
Click to expand...

Wouldn't it have been reasonable, considering cost of the Osiris, to develop a custom solution?

Here is what Benchmark did. I have no idea if this is a custom implementation or 'off the shelf' but it ads perceived value to an expensive product plus technical advantages, at least according to the marketing blurb. Benchmark usually measure well.

https://benchmarkmedia.com/blogs/application_notes/benchmarks-256-step-relay-controlled-attenuator

My OP doesn't just apply to Rega. I do wonder if conventional volume pots belong in expensive products.
 
I removed the motorised Alps Blue on my Sugden A21Se and substituted it with 2 cheapo (18 euros) Chinese stepped attenuators off the Bay, one for each channel using the input selector knob for the right hand so as not to spoil the front panel ´cos I only need one input, vinyl, which I left as default. I can return it to original when and if, which I doubt. None too keen on the "feel" which is loose and lacking resistance but much cleaner as if a load of sediment had been removed from my petrol tank. I suspect those TDK and others are probably better.
 
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In the past we have employed stepped attenuation (Rega Elicit) but my personal preference from a sonic perspective is a conventional volume pot.

Runs for cover......:eek::eek:
 
The unjustified blind faith that Naim apparently has in these god-awful contraptions is precisely what drove me away from Naim.
If you want to hear how bad an Alps pot can be, have a look at Naim preamps and integrateds.
 
paul darwin said:
In the past we have employed stepped attenuation (Rega Elicit) but my personal preference from a sonic perspective is a conventional volume pot.

Runs for cover......:eek::eek:
Click to expand...

Hi Paul, interested in your reasons for preferring a "conventional" - is it the actual sound or feeling that you can't get exactly the wanted volume level with a stepped ?(my only experience of "stepped" is my bedside radio which drives me up the wall either being too quiet or too loud :)).

In my main system I use a passive with "conventional" and have toyed with the idea of "upgrading" it with a stepped attenuator, so would be very interested in your view.
 
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