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Help and Advice Needed: Cary Audio SLP-05 Preamp RMA Disaster

First, I want to thank everyone. This forum has been one of the best sources for information about gear, and I have used it extensively for years.

 

I am in need of help and advice on how to proceed from here.

The preamp is a Cary Audio SLP-05 Ultimate w/ Kimber Kable Upgrades.

Does anyone have an issue with the volume on their SLP-05 not fully muting when the knob (not mute button) is turned to zero, and do they have significant crosstalk between the channels?

This is only with XLR in and XLR out.

In particular, I would like to hear from people with DAC's with a rated voltage of 4.5V or more on XLR. This is about every high end DAC like the Holo, Chord, Auralic, and even Cary offerings, as well as DACs from Matrix, and other entry level high-end DAC's

 

My Gear:

i9 based server running HQPlayer Embedded and Roon Core.

Sonore Optical Rendu, Holo May KTE DAC, Manley Snapper Monoblocks, 6Pi Cornerhorns.

 

The story is a bit long,

so here is a TLDR;

My SLP-05 preamp does not mute when the volume is turned to zero (mute button works fine), and has significant cross talk between channels. I can input a 1KHz test tone into the LEFT channel (not other inputs), and hear it clearly from the RIGHT channel with the volume turned to zero.

Here is an unlisted video that I sent to Cary demonstrating the problem.

Cary is claiming the issue is my gear. First, they claimed my amps have too much gain (it has less than the Cary amps), and too many watts (watts?!?), then my speakers are too sensitive (102dB). They finally fixated on my Holo May DAC having too much voltage at 5.8V on balanced (the Cary is rated at +/-3V, or 6V). They remained fixated on this even though I provided the above video using the Matrix DAC which is rated at 4.5V.

 

I measured the voltage coming out of the Matrix DAC as shown in the video at

    

pin1-pin2

pin1-pin3

pin2-pin3

Matrix DAC LEFT

1.085V

1.084V

2.170V

Matrix DAC RIGHT

1.083V

1.081V

2.164V

 

which is very close to what they claim is "standard."

Cary is being resolute in stating that they have sold thousands of these preamps, never had this problem, and my case is unique. It seems I am the only owner of a Holo May (or Chord, or Auralic, or...) and an SLP-05...

 

Advice needed:

Cary is proposing modifying the preamp as follows:

1) Relocate a capacitor that is getting charged via the ground plane near the input buffer tube, and isolate the input buffer ground.

2) Tie the floating XLR neutrals to ground at the relays (this will short the inputs when an input is not selected).

3) Add a 5:1 voltage divider across the input for XLR 1, and RCA 1 to reduce the inputs from 5V to 1V. I do not know what they propose to use for the ground reference here.

I would like some feedback on these mods. I think some of these are pretty questionable. Why tie the relays directly to ground when it might be better to tie them through a 1M resistor? Tying the XLR neutral to ground seems like an invitation for common mode distortion and might prevent the circuit from being fully differential. 

Moving the cap seems fine, but it does not address the core issue - why are we having ground plane issues in the first place?

----------------------

The story as briefly as possible

I want to be clear up front, that I never engaged in raging, yelling or name calling, I never made any demands other than "you have to make this right." I did express myself as being "very upset and angry," and in a later email, "Please understand that my trust is pretty much gone at this point."

I RMA'd my 2 week old SLP-05 because the volume would not fully mute with the volume control (mute button works fine). While they had it, I paid ($250.00 + $250.00 shipping) for the gain reduction mod.

They could not find anything wrong performed the gain reduction mod, and sent the preamp back to me.

When I powered on the preamp, it was DOA. It turned out FedEx dropped it hard enough to knock the rectifier tube loose, and break the straps holding the big power capacitor down.

I found the gain reduction had no effect that I could determine, it is too loud at 10:00, and almost impossible to adjust to a low listening level.

I found the signal still bleed through at zero volume, and I found that the left channel bled through to the right channel.

 

What ensued was a steady stream of what can only be called BS (or "nonsense" as I referred to in my emails) with the Quality Service Manager. When it became clear that not only was I being not being listened to and there was a lot of CYA going on, I called and asked for the contact info of someone in authority to monitor the situation. I was given the email of the owner, who it turned out was never told about the shipping damage. I was finally issued an RMA 3 weeks after getting my preamp back.

 

They once again could not find anything wrong.

I had to actually write out an experimental plan for them to duplicate the issue.

As far as I know, they did not test another preamp with or with out the upgrades to see if the issue is unique to my unit or not.
 

It is clear to me that Cary does not want to know if there is a problem.

I am at a near loss as to how to proceed from here, and I could really use any input you good folks could provide.

 

Thanks you,

-Josh

joshua43214
roxito
23 posts
 

@joshua43214

Really glad you shared your experience. Now I am hesitating to deal with Cary Audio’s after sales support. I left a voice message on the Cary Direct sales number, but they never called back. It is absurd that they dont have a return policy if you select their factory upgrades (per the website)!

Couple Qs:

1- Am also concerned if my setup will need additional attenuator with SLP-05. My Terminator DAC has an o/p 4.6Vrms on the XLR. My power amp has a 29 DB gain. Speaker sensitivity is 88db.

2- Have you found an alternative to SLP05 ? I have similar requirements (balanced, remote, tube, ideally 6sn7)

avanti1960
1,480 posts
 

in all fairness to Cary dealing with nearly double the recommended input voltage that the OPs DAC has in balanced mode is a tough thing to accomplish.

in fact I have read in other manufacturer’s amplifier and preamplifier manuals that input voltages of greater than 2.5 V from a source may have some bleed through even at zero volume control.

not trying to be a Cary apologist, just that manufacturers design for a maximum input voltage. if that voltage is 2X the specified amount, you may have some bleed through.

personally not a big deal and easily fixed by using the single ended output on the DAC which would have cut the output voltage in half.

Manufacturers try to design for typical nominal source voltage which is usually no greater than 2.5 volts as is the case of my Luxman DAC and Sony HAP player.  Turntable phono preamps are even much lower at ~ 1 volt output or so.  

Designing for 6 volts input sensitivity would cause other affects and compromises to the lower voltage sources and affect their dynamics and volume level.  

immatthewj
2,035 posts
 

I left a voice message on the Cary Direct sales number, but they never called back.

@roxito  , maybe it is due to the holidays.

But I can tell you that, unless things have recently changed, they no longer offer telephone tech support.  The last time I needed tech support I had to send an email, & it took a while to get a none too helpful email back from them. 

joshua43214 OP
49 posts
 

I want to thank you all again.

Sorry to get back to this thread so late, my internet was down until last Thursday, and I have been getting caught up with other things after getting back from vacation.

 

I have spent much of the last week reviewing my notes and thoughts that led to my initial purchase of the Cary, and used that plus this experience to chose a replacement preamp. I chose to go with a BAT VK-33SE, I think it might synergize better with my Manley Snappers.


It is interesting to note that many manufacturers publish the rated input voltage, Cary does not. Imagine how much different my experience would have been had they published this info. They could have simply pointed at the spec, told me to find a way to meet it. I would have simply sent it back and taken responsibility for not doing my due diligence, as well as the loss for shipping and restocking. In stead, they wasted months on passing blame around and covering each others butts, and made me a very unhappy customer who will be happy to share my experience with others.


In fact, I most likely would not have purchased it in the first place because I do pay attention to details like this.


I disagree with the comments that it is difficult to design the amp to handle higher voltages - it is actually easy. One needs simply to attenuate the signal before the input buffer - the SLP-05 does this on the RCA inputs, but not on the XLR inputs. I assume this is to save on cost and complexity since attenuating both legs of a balanced signal requires well matched components. This is the reason the signal was bleeding through at zero volume.

The source of the cross talk, and why the signal bleed affected the right channel more than the left is from a poorly located capacitor, and Cary was able to cure this by relocating it.

These are two separate design issues, one is a design choice, the other is a design flaw in the layout of the PCB itself.
 

It is my belief that Cary knows there is issues with this preamp. Considering the review linked by @decooney above showing pretty poor performance with respect to cross talk, it is impossible to imagine they are not aware of this issue. 

Judging from my experience and others, I think Cary has lost its healthy organizational culture, and is on a downward spiral.

 

Thanks again,

-Josh

 

avanti1960
1,480 posts
 

@joshua43214

Cary should have specified an input sensitivity spec in their manual, agreed.

However your DAC’s output voltage is exceedingly high with the XLR connections basically 6 volts, more than double the typical source output voltage. Many preamps would have trouble with 6 volts input. Included below is a note from the

manual for the Luxman CL38uC tube preamp stating the issue if input voltage is higher than 2.5 volts.

FYI the input sensitivity on you BAT is 3.0 volts, you may wind up having the same problem.

Also the full Class A circuit Cary SLP-05 is one of the best if not the best sounding preamps on the market. I have had nothing but courteous and prompt service when dealing with Cary.

To suggest that Cary’s culture is on a downward spiral because your source has 2X the output voltage than most preamps can tolerate is ludicrous.

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