"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

@xcool 

not sure if this is still relevant to you but when I had the Parasound a21+ and then the JC5 amps, I got the best sound by running both the Cary and the Parasound amps with trim levels at 50%.  

Reducing the gain on the Parasounds back panel to 50% and the Carys front panel controls to 50% gave me the best sound using balanced connections.  I know the manuals say to use 100% on the trim controls for best sound but that was not the case for me- try it if you can- 50 / 50.  

Also I am going to get the gain reduction mod from Cary because my amp does not have gain trim like the Parasound. 

@avanti1960 Ooo I have heard the DeVore O96 with a top end Hegel setup and I was very impressed how fun and engaging that speaker is.  If I had a smaller room that would be the first choice to re-investigate.  

Last summer I purchased several precision resistors at varying Ohms to see if I could come up with XLR attenuators.  Think a few bucks each 0.1% metal film.  No matter the schematic (T U etc) or attenuation calculation, it sucked some of the life out of the music.   Back to an earlier point, the 6SN7 are higher voltage, low current and they won't be able to deal with low amp input impedance or high attenuation without significant engineering.  Too bad, I had hopes!

Please let us know how the gain reduction affects your system!   Note, did you reach your 15dB preamp happy spot using the loudest streaming material?  Seems like the streaming industry is going to stick with max volume unless Europe smacks them around a bit.

@jaybe  Grats on the Raven!    Now that you have had a number of months with it how do you like the character of the pre?   I have looked at the specs and followed the discussion here on Agon where Mr. Sachs and Mr. Olsen chimed in.  What caught my eye was the use of the step down voltage/step up current transformer on the output stage.  That could potentially solve all my complaints about Cary gain and allow me to use the XLR inputs on my Pass (20kOhm).

 

I have also done a fair bit of tube rolling the last year.  My impressions of the difference between RCA and XLR have changed a bit.  I still find the RCA warmer, the XLR brighter.  However the RCA input stage does strange things to the sound compared to DAC straight into the amp.   I have tried a bunch of tubes in the input circuitry and until I grabbed another pair of the Linlai Elites I couldn't figure it out. They are very clear, layered and pretty in the sound, and in comparison I find NOS tubes (early 50s, GTA/B) to be on the murky side.  Think soft focus film vs clear.  My current working theory is that the SLP-05 was voiced for XLR input first, which creates challenges for a completely different circuitry input design.  But, as others here mentioned which I can hear more clearly now with the Linlai elites, it can be a bit overdriven in the highs.

At the end of the day it is still a very nice sounding pre, but with impedance and gain matching challenges.

 

 

 

@avanti1960 do you know how the Cary modification reduces the preamp’s gain?  Do they increase the value of the cathode resistor in the first gain stage or reduce gain by lowering plate-load resistor values?  

 

 

@khloebo 

I tried 10db attenuators and the sound was not bad- probably could live with them but since the gain reduction service is available I decided to do that.  Not quite 15db but 17db which should be fine.  The full bore 23db was often acceptable sounding.   Success of attenuators working seems to depend on speaker sensitivity- higher the better. 

@testpilot 

I am not sure how they will achieve the reduced gain it but it will include "new components".