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

The RCA out on your DAC has about half the voltage as the XLR, any reason you would not use them?  

The problem does not exist with RCA input.

I only tested it with an RCA analog cable (Audioquest), not a properly rated SPDIF data cable.

 

I think I get where you are going with the idea since SPDIF cables are rated to have very specific characteristics.

 

Thanks,

-Josh

@acresverde

I did not try swapping for different cables, but I did think to verify the pins are correct.
Also, Cary was finally able to replicate the issue with their cables and gear.

@avanti1960 

Why not use RCA? Aside from the generic benefits of XLR, both the Holo May and the SLP-05 are reported to have the best output using balanced. I have found this to be true of the Holo May, but I have only listened to the SLP-05 for a few days in the 3 months I have owned it since it has been at the shop the rest of the time, so I can’t comment on sonic differences.

Also, using XLR lets me have a fully differential system from DAC through amp.

Thanks,

-Josh

@joshua43214

Post-1: "Cary is being resolute in stating that they have sold thousands of these preamps, never had this problem, and my case is unique."

Post-6: "Also, Cary was finally able to replicate the issue with their cables and gear."

 

Huh - confused - How so?

Were details shared about how they were able to replicate the issue?

@decooney 

Huh - confused - How so?

Were details shared about how they were able to replicate the issue?

Sorry if I was not clear.

I could feel my blood starting to boil again when I was writing the details. This whole affair has been the worst customer service experience I have ever had.

 

Both of statements are true:

Cary is being absolutely resolute in stating that my situation is entirely unique and caused by my "unusual" gear.

It took 3 weeks of wrangling before they finally RMA'd for the damage FedEx caused. They never issued and RMA for the signal issues, and they where only able to duplicate the issue after I gave them explicit instructions.
here is the email I sent them regarding instructions:

On Nov. 2, the day my SLP-05 came back, I emailed you. On line 3 of that email, I stated the amp would not turn on, and described the loose tube and capacitor. Near the end of that same email, I mentioned that FedEx could be blamed for damages. I did this intentionally to provide Cary Audio and honorable path to address my issue and get the preamp back.

 

I do not understand how you can say you did not know about the damage.

This is just one of the many examples of why I feel like my concerns have not been heard or have been brushed off, and is the root of why I am so upset and angry over this entire affair. Add to that, what knowledge of electronics I might posses has not been considered when making what are obviously nonsense replies.

 

If you have not duplicated the results, it is because you have not duplicated the experiment.

I suggest using the test tone I provided in an earlier email.
I suggest ensuring the voltages measured using that test tone match or exceed the ones provided for the Matrix DAC in that same email.

 

pin1-pin2

pin1-pin3

pin2-pin3

Matrix DAC LEFT

1.085V

1.084V

2.170V

Matrix DAC RIGHT

1.083V

1.081V

2.164V

I have attached the test tone wav file again.

I suggest not using a speaker with the sensitivity of a brick.

Note the above voltages are not far out of line with <Tech>s Nov. 18th statement "...standard line-level signal (typically 1-2V RMS)." I will not debate the validity of the statement, just point out (again) that Cary DACs are 6V RMS, as well as other standard high end DACs (the Chord Dave for example).

 

I make these suggestions as a person who not only designs and analyzes experiments for a living, but often has to duplicate the results of other scientists.

it was after that email that they duplicated the problem, and made the suggestions I detailed above.

 

Thanks,

-Josh