"Too much gain"? (Cary SLP05 question)

A few days or so ago, someone had revived an old Cary SLP 05 thread, and common to that discussion seemed to be the subject of too much gain. 

My first question is:  does compensating for too much gain by simply adjusting the volume knob knob down degrade the sonic quality?

My second (2 part) question relates to this quote from one of the replies in that thread:

 A quick note to Pass Labs and they suggested a pair of Rothwell 10db balanced attenuators into the amp’s inputs.

What exactly do balanced attenuators do to resolve this issue, and if placed between the preamp and the amp, would they degrade the signal path & therefore the sonic result out of the speakers?

I am a relatively new owner/operator of a SLP05 and it is in front of one of the earlier Cary V12s.  I did find those balanced attenuators on ebay for (I think I remember them being) $89 a pair, which I find totally doable.  I am lsitening in a (very) near field room right now, and it seem as if I do have a lot of gain.  Generally the big knob is on 9 o'clock plus or minus a little bit depending upon the source material I am listening to.  I am using the balanced ins and outs to & from my SLP05 and I have been given to understand that using RCAs would reduce the gain somewhat.  I do have some RCAs (I am presently using Kimber Silver Streak balanced interconnects) but my collection of spare RCAs is Kimber PBJ and Monsters. 

For $89 should I try putting a pair of those  of Rothwell 10db balanced attenuators into the balanced amp’s inputs?



@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.


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 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.


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.