"Too much gain"? (Cary SLP05 question)

Hello all,

I thought it would be worthwhile to add to this thread as the unit does have a ton of gain that will severely limit use of the main volume pot. After reading through this thread and others, there has been some good information and some incorrect conclusions. I thought I would relay my experiences here to help future owners resolve the question of what to do with the excessive gain in a pre that they love.

First, let’s be clear what the circuitry is. ALL inputs, xlr (via input tube buffer) or rca get routed to the right and left input trim pots. The pots are a cheap Honeywell plastic potentiometer, 100kOhms. Recommended use for this pot from the Honeywell sheet is in ATVs, joystick controls, and more. Ruggedized for military standards. These Honeywell pots are directly wired to the two plastic potentiometer layers of the Alps 100 kOhm pots, which has a motor control. So you can use either the trim pots or the volume knob to control volume, or both. It doesn’t matter electrically, you just have 2 pots in series.

I have played around with the pots on the Cary, as well as digital attenuation. Re digital, some software driven attenuators are definitely better than others, but it seems like -10- to -15db is the limit where I don’t hear issues in volume matched back to back comparisons. Yeah, I know it shouldn’t be the case mathematically, but something is off. Besides, even -30 or -40 db digital attenuation isn’t enough to give you full use of the volume knob. So that isn’t the answer.

Playing with the pots is interesting, because you will quickly notice with volume matched testing that the balance trim pots are clearly filtering the signals. This shows up with low level information at all frequencies, but it is most easy to see with higher frequencies. Maybe a system runs a bit bright? Well ok, but the full spectrum loss of clarity and detail is not a favorable trade. Buy tubes that are rolled off on top, *cough* I meant warm sounding.

Playing with the Alps volume pot gives similar results, but with less severity. The channel imbalance near max attenuation is a problem though, as is the high frequency filtering which makes the bass seem exaggerated.

So what are the solutions? I guess you have to decide what you want out of this pre. Do you use the headphones a lot? The input trim will likely be important unless your tubes are perfectly balanced. Input trims are useful for troubleshooting, but that is limited case scenario when it is also easy to just pull a cable. Only use the volume knob and you just want it to work better?

If you want it all I would look at replacing the volume and the trim pots with high quality stepped attenuators. Goldpoint,Khozmo, or others are good examples. Yes they are expensive. But your $6-8k amp deserves better than 3$ and 12$ pots. I put in a 24 step mono 100k pots in place of the trim as I don’t use headphones. If you do, maybe see if 47 step will fit.. First off, night and day improvement in clarity at all frequencies, you will sit up in your chair. Second, with high quality pots you will notice that the Alps isn’t exactly bad. If you do most of the attenuation with your stepped pots, then you can run the Alps from 12o’clock to full on with good results. In messing with this configuration over the last month, I would say that the less the Alps is in the chain, the clarity improves but with diminishing returns. My next step will be to replace the Alps with a 47 step attenuator and call it good. The upper range of the 24 stepped input trim is just a teensy bit limiting in my system.

Motorized volume knob mandatory? Well there are solutions depending on the attenuator you choose, but they are expensive. I would go this route if you plan to keep the pre for as long as you can. I haven’t decided what to do yet, I might see if I can use the existing RC design and fabricate an adaptor for the new attenuator. We’ll see.

Hope this helps. Yes, get a professional to do the work and the usual disclaimers. I have no knowledge of EE or circuit designs, these conclusions are my own experience and you may get different results. Make modifications at your own risk.

@immathewj

I have learned your issue the hard way having bought a power amp with 26db gain for my Cary SLP-05 (Pass Labs XA30.8).  Even when the Cary's gain is backed off to half (going any lower affects dynamics) there is too much gain in the system. 

I tried the 10db rothwell attenuators and did not care for the results.  

I also tried using the RCA outputs which drops the Cary gain from 24 db to 17db.  This definitely helped but I lost a lot of the 3-D huge soundstage when not using the XLR outs on the Cary, the balanced outs run through another set of tubes and the sound stage is much larger and the sound is ore dynamic.  

Ultimately an amplifier with 23 to 20 db gain works best- or an amp with adjustable gain like Parasound a21+ or JC5 which I run at about half gain.  

@immatthewj Definitely think you will be happy with your decision. I went through the same litany of issues running SLP-05 into Pass X250.8. The Rothwell’s have worked out great. I usually run main volume pot between 10 and 1 with small. Balancing L/R pots at 100% and system is dead silent and very dynamic.

@harpo75 Thanks for the clear explanation on balanced gain, pot issues etc. i run balanced from the Cary to the Pass and my analogue from the phono preamp to the Cary. I actually loved the extra balanced dB bump on the mc cartridge. I am currently running rca from my 2.0 v digital source as I have not been able to hear a difference and I like the reduced gain even at the 2.0 volts( still run main volume between 10-12 for digital) I will revisit this again but since cables are different that clouds the comparison and I want to stay away from lowering main volume below 9 o’clock. Enjoy, looks like you got some great experienced advice here.

@desktopguy

thanks for the explanation.

I am actually the OP on this thread, & one of my questions/concerns was "am I losing anything, sonically, by having to keep my volume pot backed off to a low setting?" It sounds as if I may be.

6 oclock is my volume pot backed all the way off. Normal listening volume for me depends upon the CD (how loud, or I guess how much gain(?) of the CD itself) but it is usually at or about 9 oclock & sometimes, but not often, as high as 10:30 or 11 oclock. I would think it would be screaming at me if I ever put it at 12 oclock. (Part of this is probably due to the small listening room I am presently in.)

As far as what you said about nonlinearity at volume pot extremes, a little while back ago I was messing around with a Sheffeiel Labs test CD that I bought a long time ago & I came upon a test I had never done, & that involved a test tone & the instructions were to put the leads of a voltmeter on the speker wire terminals & compare the readings of both speakers. I did note that one was a bit higher than the other, so I used one of the balance pots of the preamp to make them even. This was a while ago, but I think I remember doing tube swapping on the preamp to see if the discrepancy followed the tubes, & I was thinking, at the time (if I hadn’t confused myself) that it was following the position of 2 tubes (L & R) for the balanced inputs of the preamp.

After reading your replay, I guess I should repeat that test & see if I was correct about it following those tubes.

Anywy, thanks again for the explanation.

@immatthewj, sure. If gain issues exist in the system (in my case, due to relatively high voltage output of the upstream DAC), this results in my using the downstream volume pot (of the headphone amplifier/preamplifier being fed signal from the DAC) rotated nearly all the way counterclockwise. That means if I rotate that pot very far at all in the clockwise direction--to increase volume--the already borderline-excessive volume increases quickly and to an intolerable level.

Traditional wiper-type volume pots often exhibit sonic nonlinearity at this extreme counterclockwise rotation. Typically this is experienced as poor channel tracking, with one channel sounding louder than the other. Depending on the specific volume pot, there also might be higher than usual audio distortion at extreme counterclockwise settings.

One goal of reducing system gain via devices such as the Rothwell attenuators (installed in the RCA inputs of the amp/preamp) is to reclaim some of the lower roatitonal range of the amp/preamp’s volume pot, so I can adjusting the desired volume a little further up from the farthest counterclockwise position, thus avoiding any non-linearity at that position.

Note: with certain other types of volume pots (ie, stepped, reed-relay, or digital domain designs) there is no apparent non-linearity at the pot’s rotational extremes. Thus these pots exhibit little or no nonlinearity with in systems with excessive gain, Howeverr, there may still remain the issue of having "too few steps" for effective volume adjustment.

@desktopguy 

could you explain to me what you mean by this?

but it also risks the audibility of any channel-tracking non-linearity in any give volume pot.

Thanks.

@desktopguy ah thanks man. I read your previous post too fast. appreciate the reply though. I just ordered a set of Rothwell attenuators, so hopefully they'll do the trick. 

@docroasty, I've never heard any Cary electronics. I've used the Rothwell attenuators (single-ended, rated @-10 dB) only on the Kinki Studio THR-1 headphone amp/preamp. In that application, the Rothwells did nothing I could detect to the overall sound, beyond lowering the gain somewhat (as intended).

I'd have to hear them in a larger 2-channel system to dial in their transparent. But in in my pretty resolving, high quality desktop system, they did exactly what they're advertised to do and seemed quite transparent.

@desktopguy any feedback on the Rothwell attenuators with the slp-05? 

I don’t own any Cary gear so can’t comment on that aspect of this thread. But I surely do know about gain problems in my main desktop system. I’ve wrestled with excessive gain in this system for years, always with the same symptoms: the main preamp volume pot has only a few degrees of play at the lower/left end of its rotation, such that the lowest volume to the highest volume are adjusted only from, for example, 7:30 on the dial (the end of counterclockwise rotation) up to perhaps 8:30 or 9 on the dial for the very loudest volume desired. Not only does this deprive me of the ability to fine-tune volume easily and repeatably; but it also risks the audibility of any channel-tracking non-linearity in any give volume pot.

This situation only got worse when I went from a delta-sigma DAC with 1.9 volts output single-ended; to a NOS/R2R DAC with 2.5 volts output; and most recently, to a NOS/R2R DAC with 3.0 volts output. I got through this because the preamp/headphone amp I’ve been using, the Violectric V281, has very granular and effect gain controls, separate for the line-out vs headphone output. With both controls set at -12 dB, things have been fine, and the V281’s range of usable rotatotion of the big stepped volume pot is ~9:00 (lowest volume) to ~1:30 (highest).

Then 2 weeks ago I got a new headphone amp/preamp that I burned in and want to hear as the main system preamp/headphone amp, in order to give the overworked V281 a rest. Unfortunately, this new unit (Kinki Audio Vision THR-1) represents a "perfect storm" of excessive gain:

• It has rather extreme power (28 wpc @8 ohms down to 1.3 wpc @600 ohms). It’s really an integrated amp that lacks speaker taps
• But it has no low/medium/high gain setting. What you get is the full native gain of the unit on all downstream sources
• As a result, this amp is virtually unusable in my system for use as intended.
• But I know from burnin listening that it sounds wonderful and suits my tastes in every way.

So what to do?

First, I experimented with inserting a very good sounding, transformer-based passive volume controller between the DAC and this new amp. Doing so is a real PITA (additional run of interconnect; place 2 new units on crowded desktop instead of just 1), but with its volume pot set to -10 dB, it does exactly what I want: the volume pot of the new amp now can be used from ~9:00 to 2:00 on the dial, lowest to highest volume, which is ideal for me.

Before this thread, I’d never heard of Rothwell attenuators, though I had heard of cheaper ones that get very dicey/up-and-down user reviews, with too many comments talking about loss of transparency and dynamics. Reviews and user comments for the Rothwell attenuators are far more positive. So I just ordered a pair of 10 dB attenuators as a way to simplify my new system.

My overall point here is the gain problems are totally real, Cary gear or no Cary gear. When you have gain problems, they can't simply be resolved by using the volume pot at the lowest few degrees of rotation. That’s usually produces sonically sub-par results, plus is borderline-impossible to live with, day to day.

26db (Modwright KWA 150 SE).

@shredder 

do you know how much gain your power amplifier has?  

I owned an SLP-05 as well. It sounded great in many ways, but I ended up selling it because (you guessed it) it had too much gain (and hence noise). I tried various attenuators, including Rothwell's,  and the input controls on the pre itself, and they helped but ultimately  compromised the dynamics. I paid for the Ultimate Upgrade but the small reduction in gain was not audible to me. Cary told me that dynamics would be compromised if they attenuated further. 

I replaced the Cary with an integrated (Ayre AX-5/20) and have been very pleased.

Good luck.

Philharmonicpete - Yes the total gain is reduced about 3db to about 21 I believe on the ultimate upgrade. The reason is that the plate load and cathode resistor values were changed which changes essentially the “slope” if you will, of the sound.  This made the sound less thin and a little more full in the bass and midrange.  I liked this as I always thought the original 05, although great, was a bit thin and a hint bright for my taste. Also all the better Mundorf caps and beefed up power supply cleaned it up.  So the gain wasn’t purposely reduced (although it has more then it needs) it’s more of a byproduct of the value changes on the plate and cathode.

The headphone circuit is very good.  The only thing to upgrade there would be better output transformers to improve the bass response and overall sound quality. Maybe something like the Lundahll or Sowter or something like that.  Of course it has to fit too!  I thought it would be nice to look into but I never have.

immatthewj - By all means the SLP-05 sounds much better run full balanced.  Don’t go back to RCA single-ended.  You won’t like it after running balanced.  Balanced is fuller sounding, more dynamic, better imaging, cleaner, etc.  
Cary Audio of course won’t upgrade the controls or headphone output transformers.  They are only going to put in what they supply.  You’ll need a tweaker to do that.  I’m sure there’s plenty of people on the forum that have the expertise to tackle that if they wanted to. 

LISTEN TO THE DAM PREAMP!

The balanced connections sound noticeably better (pre outs). The balanced circuitry passes through another set of tubes. Just do a quick AB comparison. That is all it took for me. The balanced soundstage is huge and more open with distinct separation between instruments, it is really something.

Using the RCA outs the sound stage is instantly collapsed and less exciting, very obvious.  

I choose balanced every time. Give it a try from your listening position.

All right sorry! I always explain too much.

@harpo75 no, not at all! Thank you! I like the sound of tubes when everything is running good, but I really do not have the mind for comprehending a lot of this stuff.

It almost sounds like you would agree with the previous advice that @russ69 offered, which was to use the RCAs?

I guess I am feeling stubborn about that because of the $ I invested in my balanced Kimber Silver Streaks. If I do go to my RCAs, the best I have on hand (right now) are my Kimber PBJs.  (I also have a bunch of Monster, but I don't think that was ever very good interconnecting.)

I am going to continue to be redundant and reiterate that I can, in fact, find a place with the big knob where the I am good with the level--but my question was related to whether the quality of that level would be better if I could achieve it at a higher than 9 o-clock setting of the volume knob.

Thanks again!

@harpo75   Are you saying the balanced gain total  for the ultimate upgrade is now 21 dB rather than 24 dB? And does the gain get lowered with a totally single ended input as well?

Also any comments on the sound of the headphone amp in this preamp?

@immatthewj 

with the left / right gain controls each at 50 % (sounds best) 

the volume control is at 9:00 to 10:00 or so most often, moderate loud, for my higher output digital sources and 10:00 to 11:00 for my turntable.  

@xcool’s statements are perfect.  Love it. 

Although the Cary support person is very nice, sometimes he doesn’t give me a straight answer [. . .] He never really answered my question.

“Haha. Yeah. There was a time when I used to rave to anyone who would listen to me about Cary Audio’s telephone tech support. I will say no more on that subject.”

Yes, absolutely right!  Now the answers are just cut and paste.  Dan and Marc used used to be great on the phones there but there’s no more phone support as many companies are doing.  And Dennis Hadd’s statement still holds true and now even more so.  The two balance pots are even cheaper ones then they used to use.  Years ago they used the Clarostat  pots in that position.  Then when those got more expensive they change to some very cheap generic pots which are terrible. At least they still use the Alps Blue Velvet in the main volume position.  
 

Also glad you didn’t go for the lower gain mod.  Part of that mod is already in your ultimate upgrade when they change the cathode resistors. The rest is simply adding four resistors in the line gain stage to reduce the signal and I didn’t think the preamp sounded as good then.  Just lost its life. 
 

If you want to keep the two balance controls and improve the sound quality get a couple of high quality mono pots for that position.  Like a couple of the mono version Alps Blue Beauty or better.  Or better get the Khozmo or whatever.  There isn’t a lot of room there before it hits the pc board so you’ll have to measure things.  As I mentioned the value of the pots are stamped on the back of it their values. 
 

Another answer that is better then two pots, find the position that sounds best on the balance pots and, that gives you some master volume adjustment freedom, measure the resistance of the balance pots and install to high quality resistors in there place.  That will sound better then most any pot.  Of course then you have no control over balance.

What to understand in the way the 05 is that the gain of the tube circuit is set.  It’s just on.  What you are controlling is how much of the signal coming in from your source you are going to allow to go forward into the circuit and be amplified.  Now the balanced input circuit (6SN7 tubes 3&6) of the SLP-05 produce gain also.  About 9db on ultimate upgrade units and 12db on a standard one.  So the balanced input gets amplified and then routes through the balance controls and then the volume control, then on to the line stage circuit consisting of the four 6SN7 tubes 1,2,4,5. The single-ended inputs route in from the switching relays directly to the balance and volume controls.  That is one reason why there is so much gain on the balanced inputs.  Along with twice the signal from the +/- phases.  I’ve heard of people trying and I’ve tried lowering the gain into the balanced inputs from the source but I’ve really noticed a lack of dynamics and overall sound quality then. They need the +/-2V in for best sound.  Another thing to be careful of is how much input goes into the balanced inputs.  They overload the tube if you go much more the 2V per phase of the balanced signal.  Meaning balanced +2V and -2V.  Like once you hit about 2.3V to 2.4V per phase you will start hearing it distort/clip. Things get hard and bright first then fully distort.  So be careful of your balanced source components. To understand better, those two tubes are “full on” and there is no volume control in front of them. It was designed in the day when the standard source component output was 2V.  

All right sorry!  I always explain too much. 

Backing off the gain knobs gradually until it sounds best (listen carefully) and you are good to go.

@avanti1960 I am actually going to try this. With your L and R ’input level’ knobs backed off to where you feel is optimal, where is your ’listening level’ (the big knob) usually at?

Oh, and on edit:  I do have some vintage RCA black glass vt231s in my balanced input sockets (#3 & #6) and I am working on four more.  I am also working on a vintage 5AR4. 

The discussion on this topic is very puzzling.  The idea that people would buy attenuators or a gain reduction mod for their SLP 05 is something I see and hear no reason for.  

Buy a NOS rectifier and some 6SN7 tubes.  Use the balanced connections.  Optimize your interconnects.  Absolutely.  

Set the gain by listening to your highest output source with the gain knobs set at full.  According to an old Stereophile review this effectively eliminates their circuitry. But does it sound the best?  

Not for me.  Too much gain and the sound was edgy at low volume levels.  

Backing off the gain knobs gradually until it sounds best (listen carefully) and you are good to go.  It sounds amazing!  The sound will be better at the same net loudness levels.  It works!  

The Roth well attenuators work well with very minimal loss of micro detail 

in a very high resolution system, depending on quality of cables and rest od system .what is in your Cary for a volume attenuator is key, if it is a Alps volume pot that is cheap and seen as a silver round drop ,just a plastic conductive wiper.

ifitis a resistive ladder attenuators then it should not me much of a issue.

@xcool the confusion is not your fault. I just would have thought that for a job parts + whatever the hourly rate for labor is would have covered a job. I may be out of touch on that as I really try to farm as little as possible out. Like for The Ultimate Upgrade, for example, they give you what the rate is for the job (kind of like getting your ball-joints on your auto replaced); I wonder why they don’t do that for the Gain Reduction Mod.

Although the Cary support person is very nice, sometimes he doesn’t give me a straight answer [. . .] He never really answered my question.

Haha. Yeah. There was a time when I used to rave to anyone who would listen to me about Cary Audio’s telephone tech support. I will say no more on that subject.

As far as using the ’input level’ pots in conjunction with the ’listening level’ (the big knob) pot to compensate for gain, reading through the replies I have received, there do seem to be two schools of thought re that. As I typed in one of my last responses to a reply, way back when I bought my Dennis Had "hot-rodded" SLP90, Dennis must have felt that L & R input level pots were, at least to some degree, degrading the signal path (but that was 30 years or so ago he built that preamp, and I wouldn’t be surprised if the pots are better now a days). I said I would say no more about a certain subject, but I really don’t see why Cary Support cannot provide a simple straight answer on that. Oh well, one of many things in life that I do not understand.

So, not to be redundant (but I guess I constantly am), but for me the bottom line is that I can find a volume setting that makes me happy, and if there is no difference in sonic quality between a certain volume at 3 o-clock & that same volume at 6 o-clock (and reading replies, there seem to be a couple of schools of thought on that as well) I am good with it as it is. I think it would be useless to try and get a straight answer from CAD Support on that also.

Hey, it is real good to hear that you will be reunited with your SLP shortly. I bet you are loving that news. And since you didn’t mention it, I am assuming that, at least for the time being, they didn’t tell you what was broke..

Hi @immatthewj,  the cost is actually $140 bench fee plus parts and labor.  He didn't specify how much is parts and labor.   Sorry about the confusion.   Anyway, I decided not to go for that mod.

Although the Cary support person is very nice, sometimes he doesn't give me a straight answer.   I was trying find out from him whether Cary recommends leaving the left & right gain dials at maximum for best sound quality.  He never really answered my question.  Instead, he offered the gain reduction modification if I think the gain is too high.

As mentioned in my earlier post, I've been setting the gains at 3 o'clock position.   I haven't tried that many different combination of gain settings between the Cary and my power Amp.   I might try to do that when I get my unit back.    

Looks like my unit is pretty much fixed, they have been running it continuously over the weekend to make sure everything is alright.   I expect them to ship it back to me some time this week.    I'll try to post an update once I get it back.

@xcool thanks for the info on that.

Could you clarify

It costs $140 plus parts and labor.

I assume that is a typo, but maybe not? $140 + shipping maybe?

Anyway, have you been able to just fine tune with the big knob to find your "sweet spot"? Personally, I am thinking I can get the volume where I like it (although it does get there fast) but I just wasn’t understanding for sure whether the same volume would have a better sonic quality at, for example, 6-oclock versus 3-ocklock. Out of curiosity, did Cary Support offer anything on that part of the subject?

And how did you make out with the SLP05 malfunction you had posted about?

EDIT:  OOPS on that, I just reread your reply and I see you are using the left & right input level pots to compensate with.

Hey @immatthewj, I didn’t realize you’re the OP.  I think you had commented on the other Cary thread that I started.  Anyway, I just had an email exchange with Cary support about this gain issue.  Apparently they have a service called Gain Reduction on the unit to lower the gain by 6db.  It costs $140 plus parts and labor. I decided I’m not going to do that, but it’s an option for you to think about.  

Wow, thanks for all the input, everybody!   I need to sit back & digest it.

@harpo75   I actually did get this unit with The Ultimate Upgrade installed.

As far as the two balance controls, I have kept them maxed out for normal listening and in the past, with my SLP 90, I did find them useful for troubleshooting.  As far as having them taken out of the circuit, in '99 I bought my previous preamp, the SLP90, second hand from a dealer.  He told me it had been "hot rodded by Dennis Had."  What that meant was that, among other things, the balance control pots had been taken out of the circuit.  That SLP90 was a huge sonic upgrade for me, but I thought that most of the "hot rodding" that had been done to it made it totally unresellable (except to some dummy like me) so I called Cary up & spoke to Kirk Owens about undoing some of the mods.  As far as the defeated balance controls went, Kirk told me that in theory (or on paper) there was some signal path degradation, but whether it could be heard was another matter.  Sooooo, I did wind up having him put balance controls back in, and on the receipt for the work that he did, he referred to them as "improved quality L & R balance pots."  (And I did always run them maxed out, but I did, quite often, find them useful for troubleshooting.) 

I'm also a new owner of the Cary SLP-05, and I set the left & right gain of the unit to a relatively low level (around 3 o'clock position).

My power amp is the Parasound JC5, which also has a pair of input gain dials.  Parasound recommends to set them to the max.  That does seem to make the amp sound better when I was using my JC2 as the preamp.   So I kept it that way.

I did try to dial back the JC5 input gains, and max out the SLP-05 gains.   To me it sounds better with the JC5 at max, so I decided to dial down the SLP-05.  Even at the 3 o'clock position,  my max listening level rarely go past 10 o'clock on the volume control of the SLP-05.

Just thought I’d ad my two bits as I have a lot of experience with the SLP-05. I do not work for Cary Audio. First off avanti1960 is correct. The two “Balance” controls, essentially extra dual mono controls, can be turned down so you have plenty of range on the main volume control. If you want to be able to adjust the main volume control to 12 o’clock, then set it there and adjust the two balance controls until you find a comfortable level. This accomplishes the exact same thing as buying an external set of volume controls.
The main volume control in the SLP-05 is a motorized Alps Blue Velvet control. Fairly good controls. The other two balance controls are pretty cheap crap controls. And yes the quality of the controls will affect the sound quality. I know some people have wired past these two controls to get them out of the circuit and yes, it is noticeable. In the old days we used to be able to get the Tokyo KO-ON Denpa stepped attenuators which were fantastic and yes expensive! Khozmo now makes some really nice controls.
A poor quality control will add grain, noise and cause a loss of the overall clarity and smooth character of you sound, etc.

Another thing that can be done is to get the ultimate upgrade that Cary offers. One part of the upgrade is that they change the plate and cathode resistors which reduce the gain some and also improve the sound. There is a lot more done but this part is of interest to you. This upgrade is totally well worth it and dramatically improves the sound quality. I would also have them wire passed the two balance controls unless you really need them. Or purchase two really good controls and install them in place of the two inside the SLP-05. I don’t recall the value of the two but it is stamped on the casing of the controls.  I know the main Alps is 100K.

Just like any part in the circuit or a cable, etc.  The controls make a difference. Now whether your system can reveal that or you’re ears can hear that difference is where you draw the line on how far to go and how much to spend.  Don’t forget, if you add external volume controls that also means more cables.

An attenuator **is** a volume control. So congratulations, now you have two :-)

Just turn down the volume. If its not tracking well, sure maybe you need to add fixed attenuation to get the volume control into its linear range (which is why i abandoned rotary volume pots  a while ago).

4 resistors will do the trick, set up as voltage dividers.  Simplest, least sonically detrimental approach possible.  About 20 cents plus fabrication and whatever hardware you choose to use.

OK let me tell you my experience.  I have a Pass Labs CA160.8 amp connected to an Audio Research pre with Avantgarde horn speakers (16 ohm).  The gain matching was all wrong.  You could not move the volume button past a certain level without the speakers being ear splitting.  In addition the background noise was nearly as loud as the music.  Purchased a set of attenuators.  Problem solved.  Great sound … volume back under control and all background noise gone.  I bought Rothwell Attenuators on line.  You can select the amount of attenuation you like (recall there are three choices/levels).  Just buy these.  Price is OK and believe me they work like a charm.  Don’t cheap out to save $30 … these will likely be the least expensive bit of equipment you will have in your audio chain.

I would be careful with the channel volume control versus main volume. I had to carry 05 for many years, my understanding is that maxing out the individual volume controls put them out of the loop, allowing for a more transparent/better sound. I mainly used the main volume as the volume attenuator, I did not use the individual channel controls.  I use a totally different preamp now, no issues with the gain.  

"After reading through that revived SLP05 thread, it made me wonder and inquire if the same volume would sound better if I was obtaining it at a higher setting of the volume knob.  In other words, would my desired volume have a better sonic quality if it was achieved with the volume knob set to twelve o-clock or more as opposed to  nine o-clock."

 The answer is likely no. By adding the attenuators you're adding another step in the signal chain. Most of us would agree that is a bad thing. Just paint a new indicator on the volume knob. 

The reason for having a volume knob in it's "sweet spot" is that's attenuating, or altering, the signal the least possible.  By adding in-line attenuators you're working counter to this.

Thank you again to all that have offered me input on this.

@twoleftears  for the moment I will single out your reply as I can answer these questions with concrete answers:

There are two issues here, does the volume pot have an optimal operation range (typically around half way between min and max), and does the way the volume pot operates at the moment give you enough fine adjustability to hit exactly the volume that you want to listen at.

#1  That would be about twelve o-clock, and if I put it there with anything but low level recordings, it would be blasting me out of my small listening room.  It would be LOUD.

#2 Yes, I can find a level that works for me, but it gets there quick.  As previously typed, usually around nine o-clock with some + or - depending upon the level of the recording. 

After reading through that revived SLP05 thread, it made me wonder and inquire if the same volume would sound better if I was obtaining it at a higher setting of the volume knob.  In other words, would my desired volume have a better sonic quality if it was achieved with the volume knob set to twelve o-clock or more as opposed to  nine o-clock.

@russ69   when you say that an attenuator "will drive the preamp harder," is the bottom line that this is what I want to do to achieve (at least "on paper") better sonic quality? 

I had a Bruce Moore preamp with dual Goldpoint stepped volume pots. Volume was either to loud or to low, was not enjoyable. I contacted Goldpoint and he walked me through how to add resistors. I ordered some Takman resistors and soldered them in and each step was not so drastic. I could now find the perfect volume setting. I don’t know if you can add resistors but you may be able to change out you volume pot. 

I forgot the SLP has separate channel volume controls. I really don't think there is much difference between the main volume control and the individual volume controls. An attenuator on the other hand will drive the pre-amp harder, with less noise, and nearer the best operating range of the pre-amp. Not sure if it will sound better than just killing the volume balance knobs but on paper you would be operating in a better area. 

I have that same problem with my AR ls28se. Using the dac I can only go to 10 or 12 on the control before its too loud. I'm running 4 mono blocks, 2 PL evo 400 and 2 PSA 700m amplifier.  How could I incorporate this into my system?

@immatthewj 

sorry if I misunderstood.  

the goal is the best sound possible for the preamp and amp system and let the volume control fall where it may.  

in my case I started with the gain controls at max level and listened.  the sound was to edgy, like a phono preamp with too much gain, even at moderate volume levels.  it sounded slightly coarse, like you did not want to turn it up at all even beginning with low to moderate volume.  

I then backed off the levels until the sound was smooth and lost the edginess- happened to be right about mid level.  

it isn't about where the volume control lands, the gain controls adjust for the best sound though the volume range.  

i started with them at the highest setting (1) so that I knew what too much gain sounded like and (2) backing off just enough to sweeten the sound and not too much to lose dynamics and drive.  

FYI with digital sources volume at 9:00 is just starting to be fun, with vinyl the volume likes to be at 10:00 to 11:00.  

adjust the gain for the best smoothest sound starting at the top level and the relative volume level will sort itself.  

There are two issues here, does the volume pot have an optimal operation range (typically around half way between min and max), and does the way the volume pot operates at the moment give you enough fine adjustability to hit exactly the volume that you want to listen at.

Experiment with the trim levels and see if yo can hear a difference.

@avanti1960   again, I want to stress that I am not disagreeing or seeking an argument.  Only seeking clarification on this subject.  So if I use the left & right "input level" pots to control my volume, is that a better thing than using the big knob (labeled 'listening level") to accomplish my volume control?  I wouldn't be simply robbing Peter to pay Paul?

And to do this, what would you recommend?  Start with the big knob at 12 o-clock with the left & right "input level" pots backed all the way off and then advance them judiciously?

The Cary SLP-05 has a Schiit load of gain but so do a lot of other top tier preamps and it is not a bad thing.  

Easily adjustable by the two continuously variable gain controls on the front panel, one for each channel.  Also acts as a balance trim control too.  

Every preamp I have used benefited from some form of gain adjustment to fine tune the final gain through the amp, the Cary no exception.  

No attenuators required.  Easy to dial in without much effort.  

I was wrong about the price of the Rothwells...

I've bought affordable attenuators and I could not hear a difference. 

Thank you all for taking the time to respond & to educate me.  (And OOPS!  I was wrong about the price of the Rothwells--$109 = about $10 shipping.)

Thanks russ69. I have zero noise issues with any of my equipment.

Amps and preamps measure best at full throttle. The RCAs give you 3db less gain so you are in a better zone for the amps, not sure if it's audible. 

Thanks russ69. I have zero noise issues with any of my equipment. I'm pretty good at that part. I had my C20 done by Samra @ oldhvymec's suggestion. That was the best money I ever spent. 

The Cary I'm babysitting for OHM. It came in as he went out. I have my own, too. His is original no modifications. I get to side by side the two. One has all the goodies, one is stone stock.. It's kind of fun. Neither are as good as Samra's C20, that is the absolute BOMB. It works with anything and is tough as nails.. I hate the old analog pots, BUT it is the biggest part of it's charm also.

Save some money go to Parts Express Harrison Labs has Attenuator's for about a third of the price. I used the 6db version on my Audio Research SP-16 years ago. Worked like a charm.

The only problem with to much gain is floor noise usually.

I'd go to the RCAs with the PBJ cable, that should make you a little more happy. 

The only problem with to much gain is floor noise usually. If you have high gain and sensitive speakers it can be VERY noisy with certain media. I use a C20 Mac that has so much gain you have to be VERY careful. It is also one of the quietest preamps I've used. It took a few years to get there but it is black as night compared to any preamp. BTW I have a SLP-05. I just started fixing that mess. It sounds great and looks great, it still has a ways to go to catch that C20 though. I'm having a real tough time with no tone control. I'm glad I have a bass management system that is independent of preamp. Sure is pretty though. RED body black faceplate.

This is where volume control quality comes into play. Cheaper potentiometers will often be poorly matched between Left / Right channels especially at lower volume levels. The ubiquitous Alps RK27 is OK but maybe not great here, at least when you get up to the level of that Cary (I don’t know what the Cary uses, but there’s a good chance it’s this). This is why the insane Alps RK50 goes for such a premium. If you open it up the Alps RK27 is easily recognizable by its sandwich of 2 or 4 navy blue plastic "gangs" (they used to call this part "Blue Velvet") and a metal can motor & controller at the end (optional for remote volume control). The RK50 is a huge beautiful cylindrical brass beast (it won’t be this) and requires an external motor rig with belt drive to be remote controlled.

On the flip side a good stepped attenuator is utterly transparent sounding and well matched at all levels, but the steps themselves are too big on the lower end of its scale so it can be impossible to find the "right" volume when you have too much gain.

Digital volume controls give good matching and good granularity, but some will claim they don’t sound as good as the other 2 types.

Besides channel matching, the other problem with high gain preamps is that your music signal will be riding closer to the noise floor anytime you’re not utilizing most of its gain. So you’re much more likely to hear a hissss noise floor. The suggested attenuators will help BOTH your channel matching and signal to noise ratio.

The problem with some tube preamps is that it’s very easy to provide "way too much" gain for use with modern digital sources, with many tube circuits. Look at some of 1970s/80s ARC/ CJ tube preamps with ludicrous 20dB+ gains and 12AX7 tubes - this was before the digital age really took hold. Most balanced DACs push out 4 Volts. That’s way more than required to slam most amps well into clipping without ANY added gain from a line stage.