Super-sensitive volume controls - remedy?

You could try some Rothwell (or similar) in line gain attenuators between preamp and amp. They look just like RCA jacks, but they reduce gain by 10-12 dB.

The Rothwell attenuators work well but if you have that problem consistently you might consider that you've got too much overall gain in your system and look for an amp or a pre-amp w less gain. Also, some pre-amps have an internal jumper that allows you to reduce it's gain.

Go passive. However, your issue is most likely your source is too hot. This either because the engineering of the music, due to excessive compression or even high efficiency speakers being driven by too much amp.

In any case...in line attenuation or a passive pre might be in order. Or....if it is the amp.....a less powerful amp.

I know live sound is different, but when I was running sound for my bands, I set the board to run at unity gain and then used the input trims on the power amp to control the gain structure. I almost considered a pro amp just to get that level of control, but I don't want to replace my Musical Design D-140. It sounds to me that the Rothwells would be accomplishing the same thing as the input trims.

Which brings me to a couple more questions. Where are all the power amplifiers that require so much gain from a preamp for this to even become a problem? I know I've never owned one, and I've had a few. If I purchased a Parasound power amp, would I still be using only a small portion of the volume control?

A pro amp has pots to control input gain. essentially this is equal to an amp and passive combination.

Minkwelder hi.
Most sources these days have enough output on their own to drive amps into clipping and then some, so there is no need to add more gain and colouration from an active preamp.

As Raymonda has said a passive preamp will do and probably give you even more transparency and dynamics.

This one is a bargain at $49 and uses a quality 10kohm pot.

http://schiit.com/products/sys-passive-preamp

Cheers George

Thanks for the responses everyone. I guess maybe I need to rethink where I'm going with all this. The Parasound 2100 seemed like a good idea because of the number of inputs (including phono) and HT bypass and all. I actually don't have as many sources as I used to, but I've conditioned myself to want them just in case. Maybe if I found a passive like the Schiit SYS only with 3 or 4 inputs I may be able to set it up to do the front channels from my AV, my CD player, then get a phono stage........etc....etc...etc.

If you are happy with everything else BUT the volume control, try some attenuators. I started with the Rothwells, then found some Endlers, and now I have EVS nudes. They all worked well. I just worked my way up the price ladder. My issue is that my CDP output is high, but it is a keeper, so I have learned to live with the attenuators.

Do attenuators like the Rothwells impose any sort of penalty related to sonic quality? Thanks. Hope this is of interest to the OP too.

I couldn't notice any difference. It is a just a resistor in the signal path.

11-23-14: Ghosthouse
Do attenuators like the Rothwells impose any sort of penalty related to sonic quality? Thanks. Hope this is of interest to the OP too

They "can"' as they could introduce an impedance mismatch between the previous components output impedance and the next stage, the amp.

As they are a voltage divider inside and this will change the input impedance that the previous stage sees.

Especially if that previous component is a weak high impedance tube output stage, EG: tube source or tube preamp.

Cheers George

I have read some very negative things about the attenuators, but others seemed very enthusiastic about them, which leads me to be very cautious about going that route. I would especially not want to "work my way up the price ladder" for something that seems like a band-aid to me.

The Denon DL-160 I'm using has a 1.6mv output, and I get a comfortably loud volume level at about 10:00. I can't imagine how the Parasound would handle my Shure M97XE at 4mv!

My Rotel RC-995 was very high gain whether I used it with my B&K ST-140, Hafler DH-500, or the Musical Design D-140, which underscores my question: where are the power amps that need all that juice?

I don't think I'm a particularly difficult person to please when it comes to sound, but this sort of rampant incompatibility is frustrating.

The Endler and EVS attenuators are basically additional volume controls.

11-23-14: Minkwelder
I have read some very negative things about the attenuators, but others seemed very enthusiastic about them, which leads me to be very cautious about going that route.

Seconding George's comment about impedance compatibility, I suspect that a significant contributor to the divergent opinions about in-line passive attenuators is the differing impedances of the components people use with them.

Based on measurements I once made of the Rothwell 10 db attenuators (which I used successfully, btw), the measurement having been performed with a not particularly accurate analog multimeter, they consist of a series resistor of roughly 22K, and a shunt resistor at their output of roughly 11K. Which together with a power amp input impedance of say 50K would amount to a load seen by the preamp of about 31K, or roughly 28K to 30K in the case of most power amps having significantly lower input impedances. Those values will be no problem for most preamps to drive, but might verge on causing perceptible sonic issues with some, especially some tube preamps.

Also, those values would result in the power amp seeing a source impedance (the impedance it sees looking back toward the preamp) in the rough vicinity of 7K. Conceivably that could sometimes have audibly significant consequences, especially in the case of solid state power amps having relatively low input impedances, and especially if that input impedance is not constant across the audible spectrum and beyond.

This assumes that the attenuator is placed at the input of a power amp. Similar considerations apply if it is placed at the input of the preamp, except that it would be the input impedance of the preamp and the output impedance of the source component that are relevant.

So I would say that in general the in-line attenuators stand the greatest chance of producing good results when used at the input of a tube-based component that is driven by a solid state component. And in general they can probably be expected to have the worst chance of producing good results when used at the input of a solid-state component that is driven by a tube-based component. Of course, there will always be exceptions.

Finally, I would not totally rule out the possibility that a few of the reports of really negative experiences with these devices may have been the result of installing them in the wrong place or in the wrong direction. They should always be inserted directly into the input jacks of the destination component, with no intervening cable. Inserting them into the output jacks of the component supplying the signal, for example, would generally result in a sonic disaster (although it would not cause any damage).

Regards,
-- Al

Mink- Are you running the Denon into the MM or the MC phono stage? W 1.6 mV output, the KAB calculator shows you only need 43 dB gain. The Parasound will give you 52 dB gain through the MM input and a whopping 82 dB through the MC input. So you should probably use the MM input, and even then you've got more than enough gain. I cannot find any specs for your amp for input sensitivity or gain, but your speakers are very high efficiency (98 dB/w/m), so they can be driven to very high spls w just a few watts.

I obviously don't know anything about this, so I am going to shut up now. I used the attenuators between both solid state and tube CDPs, and tube integrated amp with excellent results. Best of luck to the OP.

Do attenuators like the Rothwells impose any sort of penalty related to sonic quality?

Absolutely they do!!!!!!! I tried these several years ago and they literally destroyed the 3D performance and less so, the dynamics. Horrible horrible horrible solution to reduce the gain. I have this pair in my house somewhere. If I could find them, I'd give these POS's to you for free.

I suggest you contact the company of your line stage and see if there is a parts kit to reduce the gain by 6 db or so.

Thanks for all your input. After posting, I did some searches for the attenuators and found that this issue comes up fairly often.

I am using the MM input for the DL-160 and can't imagine what the Shure would be like. As for speaker sensitivity, it obviously has played a part in this, however my concerns with the Rotel preamp occurred back when I was using Magnepans, and, as I recall, was just as bad, if not worse.

I may, as Jafox has suggested, call Parasound and see if they have a soulution, and if I find a pair of attenuators that aren't too awfully expensive, I may give that a shot.

I think I just need to do a little more homework before making my purchases from now on!

11-23-14: Jafox
I tried these several years ago and they literally destroyed the 3D performance and less so, the dynamics. Horrible horrible horrible solution to reduce the gain.

John, I know that you are a particularly experienced and knowledgeable audiophile, and I always consider your comments to be among the most reliable to be found here, but nevertheless I must ask: Did you physically insert the attenuators into the input jacks of a component, or into the output jacks of a component? If the latter, as I indicated in my earlier post it would easily explain the poor results you obtained. At least, that is, if they were the Rothwells; I'm not familiar with the designs of the others that have been mentioned.

Best regards,
-- Al

Found a helpful review of the Rothwells at "Enjoy The Music" August 2003. See link below. A few less exclamation marks than in Jafox's post but, otherwise, seemingly consistent with his observations. I see them carried by Amazon so might b possible to try and return them if they didn't work out. I think I'll pass for now.

http://www.enjoythemusic.com/magazine/equipment/0803/rothwell.htm

One of the bigger problems faced by preamplifier manufacturers is that when Sony and Phillips got together and created the Redbook specification, they really had no clue as to what they were up to.

As a result, they set the digital audio output spec at 4 volts! Why do I say they had no clue?? Because its obvious they never looked at amplifier specs, to find out that no amplifier ever made has needed 4 volts for full output.

There was also an assumption that no-one would ever want to listen to tape, tuner, phono or any other source other than digital. The result is that you have to knock the digital source signal down in order to use it. Passive can kinda sorta work in this regard but have problems, attenuators can kinda sorta work but have problems and active preamps can kinda sorta work but have problems.

If you want to get to the bottom of this, complain to whomever made your digital source! They need to set the output to something a little more reasonable- 2 volts would help and 1 volt (which was the old analog standard) would be great.

We've been building our volume controls in our preamps so that the first few steps are fairly close together to help get around this problem. We can also build our preamps so that the line section has no gain but still buffers the volume control and can still control the interconnect cable to eliminate cable artifacts. But this too is an imperfect solution. In a world where you have some amps with anywhere from 15 to 50 db of gain and speakers that are anywhere from 84 db to 104 db, there are going to be problems!!

Now, much more so than back the 1970s or 1980s, equipment matching is a serious issue.

I understand what you're getting at, Atmasphere, but even back in the 70's and 80's I don't recall using any source that required turning the volume pot up much past 12:00 on any amp I ever owned. Of course, I have forgotten a lot of things about those days! Maybe direct from a tape head?

I may be missing some important electronic principle or oversimplifying things, but it seems that the maximum gain of a preamp could be lowered while using more of the volume pot to accommodate a wider range of output voltages from the various sources.

As far as I remember the Redbook standard has always been 2v.
Just look at the first players from Sony/Marantz/Philips.
EG: Sony CDP-101 Marantz CD-73 etc.
They all have 2v output spec, which is all that's needed to drive the majority of poweramps from yesteryear or today into clipping.

All this gain with preamps today, is a left over from the days of vinyl with low gain phono, step ups, and head amps, when you needed some extra gain.

Today digital sources, including phono stages have 2v and over output and that's all needed with a passive pre or unity gain buffer to send an amplifier into full clipping, so why the extra gain??

I keep coming back to Nelson Pass's statement below.

"We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.
Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up.
Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control.
What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection.
And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp."


Cheers George

Thanks for pointing that out George. Funny thing though, we see 4 volts and more all the time, of course we get a lot of balanced line DACs and CDPs used with our stuff, which may explain the disparity.

Almarg - I bought the Rothwells to help achieve a more common volume control setting for CD to match with the Aria preamp's built-in phono stage. I tried the Rothwells on the preamp's CD input. This helped a lot to bring the CD closer to the phono's ideal listening level near the volume control's 12 o'clock setting but the result was disaster …. and out came the Rothwells.

Jafox, as I said above two posts back, they "can" be a negative.
What is the output impedance of the component before them? and the input impedance of the component after them?.
That way we can prove with math, it was a bad electrical impedance match.

Cheers George

Really the best way to do it right is to send the CDP or DAC back to the manufacturer and ask that they lower the output. Its not that hard for them to do it and usually the result is better sound in addition to less troubles.

We have tried building in attenuators on certain AUX inputs and even though the impedance was no issue for the CDP, the result was a degradation, even with super high quality resistors. IOW attenuators are not a good solution.

An option that I loved on the Atmasphere amp I owned was being able to lower the gain of the amp by substituting jumpers for one of the sets of tubes. A great option for a system with too much gain. Bravo Atmasphere for that capability.

That is how I have run my Atma-Sphere amps as well due to the balanced output of my digital sources being 4.5 and 5.5 volts respectively. Atma-Sphere also provided with shorting plugs for the phono section of my MP-3 preamp as well for an extremely high output moving magnet cartridge. Ultimately though I will eventually address the issue at the source as Ralph has suggested.

I saw an AR ls 25 mk2 for sale, that interested me. 2 questions: 1- first stage, solid state. 2- A gain switch. Is this the solution to the problem we are discussing? How it works? I also have a gain problema.

I had similar problem with the NAD C356.
The problem is the volume gain. Problem solved
with the "Goldenjacks" from England. Very good tweak.
It even improved the sound. Highly recommended.