roksan kandy input switching issue with audiolab 8200cd?

mbinz

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I bought the audiolab 8200cd a couple of months ago, and have just auditioned it with the roksan kandy k2. I took the cd player with me to addition with the amp. During the demo when we switched between inputs on the amp, the sound came out all distorted. Switching round the inputs on the amp cleared the fault. Thought nothing mor of it. Bought the last amp they had in stock and when I got it home it wouldn't power up. Over the Christmas period, they kindly loaned me the demo unit. I found that intermittently when changing input channels on the amp, I would get the horribly distorted signal again. We assumed as it had happened during the demo that the demo amp was at fault. (I have a recording of the problem I emailed to the distributor if its of any use!) I just today collected new stock of the K2 amp, and getting it home, it also exhibited the distortion when I had changed the input selection. This only happens occasionally, and always clears if I cycle round the inputs again. I have tried different cables and speakers attached, just in case, and I can always get it to happen after a few times round the cycle of input switching. I took it back, as they had one other in stock. We hooked it up in the demo room, and have not been able to reproduce the fault there at all... We are all stumped as to the issue, and if it is specific to only having the audiolab as source, or some other possible cause. Anyone have similar experience? I love the sound that comes from the Audiolab and Roksan combination, and would really like to track down the cause. As it happens on two amps when hooked to the audiolab, it seems a bit of a coincidence... This is going through qed silver cables to mourdant short ms906. I have also tried it on an old pair of tannoy 603's but it does the same. When the fault occurs, I can put the amp into 'standby', and when I put it back on it is still distorted. If I put into standby and then power the Kandy down and back on, the distortion is 'reset' gone again. :wall: I'm going to see if I can get the same issue with a different input source etc and generally have a play over the weekend; but has anyone else had an issue with the Roksan Kandy input selection or Roksan Kandy / Audiolab combination?
 

ISAC69

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Hi

It happened to me as well . look at the Roksan user manual page 9 ; the amp is very sensitive to short circuit , loudspeker impedence and high

volume level. the solution is when you are changing between inputs do it on a minimum or mute volume . it is a not big issue you will get use it .
 

mbinz

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Hmmm... I have confirmed that it only ever happens with the input the cd player is attached to, I moved it to be one of the line inputs. The cd player does seem to have a higher output than the other kit I have attached. I could understand if the output protection kicked in, but this is just simple distortion... The volume is at about '9 o'clock' position, so wouldn't say it was particularly load... I just turned the volume down to be so I can only just hear it, and yet if I switch around I can still get it to be distorted...

I have found that when it is distorted switched to the audiolab input, pulling the phone lead out of the amp and plugging it back in also clears the distortion. It isn't the amp cutting out or anything. Also, if the input the cd player is playing on; when it is switched to and it is distorted, stopping the cd playing results in 'white noise' still being heard, which I guess is what is causing the distortion... if I switch the cd player off the noise stops and is then ok when I switch it back on too. I'm not sure if the issue you have had is the same, like I said it does it even if switched to low volume... ?
 

ISAC69

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It seems that there is some problem with the CD , Did you try to play it with other amp ( not a ROKASN ) ?

I have had the same problem with my turntable . it had constant "white noise" and it seems there was some problem with its inner electric circuit ,

I got reed of it because I am not using it anymore .
 

Martinblueboy

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I have found that this seems to happen if you turn on the Audiolab and then turn the K2 on. So now I turn the amp on, let it fully power up and then turn the Audiolab on.

I was phoned at work by a panic stricken wife one day with exactly this problem; she thought she'd "broken" my pride and joy! Incidentally, that was the first time it had happened and I hadn't a clue what she'd done. Turning everything off and turning it back on seemed to sort everything out. It's happened a couple of times since then. Since turning the K2 on first and then the Audiolab, it's not happened since. I don't know if that helps but seems to work for me.
 

mbinz

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Thanks for all the suggestions so far... in answer to some points; I had the audiolab playing through a cyrus and and old moth power amp (with the cd on adjustable output) with no issues at all. The difference being that the the cyrus is changing the input selector as an analogue switch (I believe), and the moth was dedicated to the cd player, having no controls at all!

I have just tried the suggestion of powering everything down, switching Kandy main power on, the switching out of standby and then selecting cd input before powering on the audiolab. Initially works fine, but again, if I switch to another input and then back (while the cd is still playing), on occasions it still switches and the sound is highly distorted. Sometimes it is one speaker (either) and sometimes both. This is most consistent.

@MartinBlueBoy; was the issue your wife had to do with the sound being distorted, or was it the 'white noise' issue. (the only time I have heard the white noise is if it has switched to cd, been distorted, then stopped playing the cd... I have not had a 'white noise' issue at any other time...)

The one method so far that I have not had it happen, is if I ensure the audiolab is not actually playing, either stopped or paused, then switch, then start the cd playing. It almost seems that its the signal itself when active is not liked by the input of the amp, not sure if there are any sensing circuits for 'input overload' or something?

I have tried also a nad c541 on the same input, and the perceived level is about the same, (both cd players are significantly louder at the same volume setting than any other equipment, being a Panasonic dvd recorder and a nakamichi tape deck), but I can only get the issue with the audiolab, also the same if the audiolab is on a different input. One would assume the issue is with the audiolab, but if that is the case, why does the kandy only have the issue if the cd is actually playing when it is switched - unless the signal from the audio lab is upsetting the input somehow?

I have tried switching the audiolab to manual output level, and at -10db output, the issue still occurs, but perhaps not as much. At that level, the level is significantly lower than that coming from the nad (based of volume perception).

I must admit, I'm now probably aware of the issue now, whereas if I was using the amp for normal listening, I would probably either never have it happen (if for example I switch to cd without a cd playing), or it would be so infrequent as to put down to an anomaly! (If it was a mechanical switch, it could be put down to dirty contacts, and a twiddle of the knob would solve it!)

I would still like to get to the bottom of it, as I still don't think that in equipment that costs about £800 each, there should be any issue of this sort at all! If I could get the same performance from a different amp, that includes a phone input, at this price point or upto £1000, I would give it a go, but the kandy does sound sweet and I suspect I'd have to pay a lot more... I don't want to have to do that just because of this issue which is likely to happen rarely. I'm almost saying I'd live with it; but I'm not happy about it after spending this sort of money! `¬(

I'm sure if (and probably will anyway), I contact Roksan and Audiolab over the issue they will probably suggest the fault is with the other persons kit. So far though, as far as I'm concerned after trying at least three combinations, the only time there is an issue is when the kandy and audiolab are together. I also had to buy the audiolab from one dealer and the kandy from a different one as neither stocked both... oh well!

P.S. I wish we could get email notifications of replys! `¬)
 

Martinblueboy

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Hi mbinz, I'm not really sure as I wasn't there (I was at work). However, it has happened to me a few times and it's distorted sound rather than pure white noise. I probably hadn't picked up that you also have the problem when changing between inputs. I can't say that I've come across this before. It only seems to happen if you turn on the Audiolab and then turning on the K2 from standyby. Other than this very occasional problem I love the combination!
 

mbinz

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Thanks, yes it is distortion occasionally when switching to the cd channel if the cd is already playing. And yes, other than that, the roksan/audiolab combination is very pleasing to the ear! `¬)
 

deusExMachina

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Hi All -

I know Im a little late to this thread, but its good to see it as I have been having this problem and been wondering what to do...

I have just emailed both Roksan and Audiolab and asked them for a fix - I dont think this kind of problem is acceptable on kit that costs this much.

No one has mentioned this but on my combo if you use the tape out (using it for a headphone amp) I get bleed through of distored sound from the 8200 on all the other inputs - if you have the DAC plugged in it gets worse - no cool at all and nothing "clears" it.

As one of you mentioned both units are great - its just a shame that dont work together that well and a bit suprising given that What HiFi recommend this combination - I dont think that in all good conscience they should be recomending a flawed set up.
 

deusExMachina

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Hi All -

I know Im a little late to this thread, but its good to see it as I have been having this problem and been wondering what to do...

I have just emailed both Roksan and Audiolab and asked them for a fix - I dont think this kind of problem is acceptable on kit that costs this much.

No one has mentioned this but on my combo if you use the tape out (using it for a headphone amp) I get bleed through of distorted sound from the 8200 on all the other inputs - if you have the DAC plugged in it gets worse - no cool at all and nothing "clears" it.

As one of you mentioned both units are great - its just a shame that dont work together that well and a bit suprising given that What HiFi recommend this combination - I dont think that in all good conscience they should be recomending a flawed set up.
 

mbinz

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Hi, just seen your message, not sure if you are still watching here? (I don't think we get email updates for forum replies here?)

I'll check back every so often to see! `¬)

I had a response from audiolab Steve Hughes) and he did ring me as well, but they could not resolve the issue (initial suggestions were to try a reset as described in the user guide, and try another 8200cd player with the amp which was not really practical) and advised to get in touch with roksan.

I emailed the managing director at roksan who replied to me, and passed my query onto Roy Alvalle. Initial suggestion was to fit attenuators in line; but as we can set the 8200cd output to be adjustable, we can attenuate the output directly. I pointed out that by doing so, the relative levels between different inputs was then wildly different. They did respond with;-
If you are happy, willing and able to bring your unit and the Audiolab product to our factory, we would be most interested in duplicating this fault and hopefully offer a solution for you. I look forward to your reply and decision. We would appreciate the opportunity to explore the problem in the first instance.
I have not been able to do so as they are in London, but if you get the same offer, I'd be interested to know!

#############################################################################################################

I have found that the issue (for me anyway!) only occurs if you have a cd playing on the 8200cd player prior to switching the roksan to the cd input. If you ensure no cd is playing, then select the cd input on the amp before then playing the cd it is never distorted on the cd input. If you then switch to another input and the back to the cd input while the cd is still playing, it can then be badly distorted! The only way to clear it is to stop the cd playing, switch to another input on the amp then switch back to the cd input then start the cd playing again...

I suspect it is probably due to 'chatter' in the input switch circuitry when the input is switched while there is the signal playing. Why it only seems to happen with this combination, i'm not sure? I wonder if anyone else has had an issue with other source input to the roksan?

Anyway, if you get anywhere with them, please post back here if you are still watching the forum! `¬)

Cheers,
 

deusExMachina

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Update -

I have been using the 8200CD in variable output mode with a -10db cut since I discovered this problem and that seems to have resolved it.

I suspect this problem occurs (and i'm no audio engineer) because the audiolab puts out about 2.05v and the Roksans line levels are 470mV so they are being overloaded by the output - a -10db cut takes the output to approx 0.632mV so is much closer to the matched input.

I'm going to try some Rothwell inline attenuators (-10db) also so that I can set the CD player back to standard output as its a little confusing for others using the hifi and I'm afraid they might accidentally damage the amp by using the CD gain rather than the amp.

Will report back to this thread.
 

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