Does remote control degrade the sound of tube preamps?

i have just spent three years researching, designing and prototyping remote control intended for volume production.  My thesis was that it could nto only be a VERy attractive feature, but superior sonically.

The real answer is "it entirely depends on how". 

Leet's take the simplest method- a stepper motor, connected to the existing volume knob's shaft.  This will have zero impact - it mimics your hand.  So that one is 'sounds the same.

Next let's look at the traditional digital solution (e.g.: what's in your phone, mac, pc, etc). This does binary multiplication on the digital stream. Since there is truncation within the allotted 16 (or whatever) bits and no additional resolution int he DAC, this always degrades the sound. In fact at low levels the resolution falls to about 11 bits.  On the other hand the channels track perfectly and there is no additional noise,, aside from the quantization noise (which i note to keep the trolls at bay).

Next we can use a "digital potentiometer" .This is a terrible name, since they are analog and generally dual-resistor pair arrays.  Which is very good. But there are technical problems i wont delve into since they are very complex. I made tow sound really good (better than an ALPS or Nobel POT) but only at huge complexity.

Finally you can use a small embedded computer/contorller, lots of relays or analog switches, and pairs of  resistors. This is the old Mil-spec method and basically the best there is.  Old version used stepped knobs and cost the moon, both in parts and labor. They were also very clunky in many ways. But with a computer, it an be really elegant.  That is what i settled on. It makes old fashioned high end POTS sound veiled and shows thier awful tracking.  Beware there is no going back, take a deep hit and I've got oyu :-)

So the differences are very much n the details adn about 0.01% here will even understand them.  i admit i didn't fully realize what i was getting into with the potentiometer chips - such promise, and such issues.

The best solutions however are not cheap in either engineering or parts,

G

Yes there are MANY ways to employ both manual and remote volume control.  One of the most interesting is the EMIA approach of using an auto-former with many discrete taps that are relay switched.  I believe there are other transformer-based volume controllers, some even utilizing remote switching.  This probably represents the most complex way of doing volume control.

I also like the approach of having only one fixed resistor in the signal path, with volume determined by relay switched set of resistors shunting part of the signal to ground.  

+2 Mapman, couldn't have said it better! At my age, 80, I wouldn't consider a preamp without a remote control. My ears are the limiting factor now, a remote is the least of my worries!!!

It’s like buying a multilevel house when you’re 70 where it’s very possible you won’t be able to reach the second floor at some point. Even an injury with a recovery period Will totally disrupt your life.

So if you’re going to buy a preamp and have it around for a while you’re really appreciate necessity of a fully functional remote.

My impression is that manufacturers are being extremely lazy by not doing a fully functional remote. There is no sound impact. Most will likely take interest in the additional cost.

Further what if you put it in a second room how inconvenient is this?

@music_is_life

Thanks for @ blackdogs reference. Helpful in seeing where he is coming from, a competitor. His examples of “crappy integrated circuit volume” used in Audio Research equipment who’s sound “has been ruined” … making it a very inferior product had me question his motives. I have not found that to be true. In fact, I think this is a very self-discrediting statement.

I have had a number of products with discrete volume controls and not found them to be greatly superior to alternatives. High end audio component are composed of hundreds and hundreds of design decisions and components and singling out and slandering a single component as a fatal flaw on some of the finest equipment manufacturer seems a bit irresponsible… especially coming from another equipment manufacturer.

Hence the reason for my question. It was clear he had a chip on his shoulder… now it is clear from whence his prejudice comes.