"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

Showing 17 responses by immatthewj

@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?

 

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!

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.)

@voodoolounge   this is strictly a question, not a question looking for an argument.

Why is a lot of gain necessarily bad? Does having more "real estate" (as I have hear it referred to) to utilize on the volume knob improve the sonic quality?

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? 

 

 

 

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.) 

@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.

@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..

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. 

@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

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.

 

 

 

 

 

I found after considerable testing that the XLR inputs and outputs of the Cary sound different (edit: compared to RCA).

@khloebo , my impression is the complete opposite.  I have found that when comparing SQ of the balanced circuit vs the RCA circuit, that after listening to my system using the XLRs the sound stage seems  folded in or collapsed when I use the RCAs.  

Out of curiosity, and not that it would have anything to do with perceptions of balanced vs single ended ins and outs, does your SLP-05 have the Cary Upgrade package?  

@khloebo , from reading your posts I have no doubt that you are way more tech savvy than I am (and in case that sounds like it might be snark, I am totally sincere) and I didn’t put as much science and knowledge into the comparisons that formed my perceptions as you have.

I acquired mine in ’21 from Cary’s preowned page, and from my memories of the emails I exchanged before I pulled the trigger, it was 8 years old at the time (it is one of the ones with the indentations on the power supply for the preamp feet to sit on, although I don’t have mine set up that way).  When I called Cary on the phone (they will talk to you on the phone if you want to buy something) to close the deal, I decided that I may as well do The Ultimate Upgrade at the same time, and an added "bonus" would be free shipping (no free shipping on preowned, but if one was to send a preamp to cary for the upgrade, Cary would send it back after the work for "free") even though that meant that once the upgrade was done I owned it even if I didn’t like it.

But to understand where I am coming from with my perceptions of the SQ, up until that point I had been listening to a SLP-90 which I had owned since ’99.  And the SLP-90 replaced a B&K digital HT preamp, so as you can see, my experience playing with high quality preamps is, to say the least, limited).

The SLP-90 was a huge upgrade in SQ from the HT preamp, but it was starting to sound as if it was getting tired.  So the fact that I was listening to a 30 year old preamp probably has a lot to with why I like the SLP-05 as much as I do, although I will say that the SLP-05 sounds a bit (or maybe more than a bit) cool and clinical in comparison with my SLP-90.

As far as my balanced input tubes, that’s something else I am doing different that makes RCA vs XLR not a fair comparison.  A friend from another site turned me on to a literal plethora of PAIRS of vintage 6SN7s (note that I emphasized ’pairs’) so after playing around with those in the balanced slots, I did note that some of them really really shined.  At the moment I have a pair of National Union 6F8Gs (obviously with adapters) in those slots, and they really do it for me some nights.  And prior to putting those in, I was giving a pair of Sylvania ’52 Bad Boys an extended spin, and they were making me happy, but for different reasons.  I also found two different pairs of VT231s  in that plethora that I thought were audibly better than the rest, with my favorite being a pair of black glass RCAs which made detail and separation stand out much more clearly and cleanly. (There were also pairs out of that fore mentioned plethora that I was not sure if I heard any discernible difference or not, and there are actually pairs of both 6sn7s and 6F8Gs that I have yet to even try.)  

So with that all typed, I realize that you were making your observations re XLR vs RCA with all tubes being equal.  

Back to the pots:  what you typed about using the input level pots in conjunction with the main Alps pot was quite interesting, because in my near field environment I am usually at 9 o-clock + or - a bit, and that, of course, is with the input level pots turned all the way up.

My vision is not very good anymore and also I am a bit dense when it comes to understanding  this stuff, but it sounds as if what you have been saying is that to get the best SQ given some of my other limitations also means lowering the gain and if I am stubborn about XLRs the next best would be to upgrade the two input level pots and use them for volume control with the main pot turned all the way up?  Or at least set the upgraded inputs low enough so I can run the main Alps at 12 o-c-clock or close to it?

Forgive me  if that is not what you have been saying. 

(Okay, so now I note that you said that basically the Alps is not at its best at the bottom OR TOP quarter . . . meaning that I would not want to run it all the way up if I was combining it  with the input level pots for volume adjustment.)

Regardless, unless I am totally misreading, upgrading the input level pots is definitely recommended.  Even though I make no claims to be a tech, I do have experience soldering and de-soldering . . . how tricky a job is replacing the pots on this unit?    

Having said all that, nothing needs to be done when you love the sound, XLR or RCA. 

Well, there are nights that I am in love.  But who doesn’t want more and more love?

Hey, thanks for your contribution to this thread!

@khloebo , although you addressed this to  @avanti1960 

 I should go back and see if the rectifier tube actually does anything for me. 

I have rolled three 5AR4s (the original Sovtek, a GL, and a Mullard with Amperex brand on it) and I cannot say that anything reached out and slapped me on the face.  But with that typed, I do not possess golden ears and there may have been a difference that was subliminal, meaning the way I believe  my ear/brain connection works is that I may be enjoying something either more or actually less, but it is a subconcious type of thing that results in either pleasure or displeasure.  If that makes sense, because it is a concept that is hard for  me to put into words.  And it makes A/Bs hard to do for me.  

I also have a couple of 5AR4s that I picked up that I have yet to try yet--an actual Dutch Amperex and a Japanese tube . . . maybe a Nakamichi?  I’d have to go back and fid it and look at it.  Someone on ebay was once selling some 5AR4s that they were saying were the "Japanese Mullards" (which I had heard of before) and the way I was doing ebay binges,at the time, I am surprised now that I didn’t buy one of those also.

A PS on edit:  hogging out those holes for the upgrade pots makes be a tad nervous, I will have to think about that.  I may try to get back to you on this project.

Check remote function.  In my unit, it controls volume and nothing else.  The buttons are for the cinema unit I think.

Volume is all that  the remote does for my SLP-05.

By virtue of the high gain, I’m assuming the volume will be set relatively low when the 2 gain pots are full on. This to me seems like the volume adjustment will be difficult, as even small adjustments will result in big changes.

I use the balanced ins and outs and I feel the soundstage is more open with more bloom that way; however, there is not a lot of available real estae on the main volume knob in my small room.  But that part really didn't turn out to be a big issue . . . my main concern is whether it would sound better if I could get the same volume with the pot in a higher position.

Aric has been very helpful in our emails and I feel he would be a great guy to deal with if I were to own one of his units. The communications from Cary have been somewhat different.

Tech support from CAD used to be soooo good.  That was part of what made me a fan of Cary in the old days.  Their customer service has changed a lot.

@testrun , don't you have the factory remote anymore?

@jaybe , I had sworn off Cary myself, but then this preamp came up on their preowned page at a price I could do, and before I had sworn Cary off, this was a pre I had heard great things about and I had always wanted.  Combine that with my previous preamp (SLP 90) being ancient and sounding tired, I did some soul searching and then did the fickle thing and pulled the trigger.  And in my system it has been transformative.  

@testrun , I am not attempting to be sarcastic, but if all you are using the remote for is the preamp, how could it get much simpler?  I mean it has an up or down for the main volume knob and that's all that applies to the preamp.