[Barry.B]

Hi All,

I am currently using a Meridian G08 CDP as a transport (couldn't wait for the Bryston CDP to arrive in the UK - but may regret this!!) using the S/PDIF output feeding the DAC in my BP25DA via a Chord Prodac digital interconnect.

The snag is that I am getting intermittent drop outs in the music when playing a CD which is getting very frustrating, these appear to be totally at random and occur irrespective of the condition of the CD playing surface etc.
The G08 has had a recent drive change by Meridian UK so in theory that should be Ok, but it's a DVD rom drive so you never know!

I spoke to one of the Meridian service engineers today for advice.  His comments (my interpretation of his description so this is not to be taken as a quote please) were that as the G08 upsamples to 24 bits and 88.2 kHz the DAC it feeds needs to be able to read at least 24 bits and 96 kHz or there is a possibility of it being temporarily "overloaded/choked" causing the drop outs in the music.

The Bryston DAC according to the BP25 manual has an input sample rate of 16-108 kHZ and can read word lengths of 16, 18, 20 and 24 bits so that should be ample and it also upsamples. Would I be right in assuming that the signal would be upsampled twice, initially by the G08 and then again by the Bryston Dac?

The G08 S/PDIF output can be set to 44.1 or 88.2 kHz but it sounds better using the latter, but the drop outs occur using both settings.
Is it possible that there can be a conflict between the G08 S/PDIF output and the BP25DA input that would cause these drop outs?

The whole point of purchasing the BP25 with the on board Dac was hopefully to be able to use a high quality CDP/transport as a source and then let my Bryston/PMC system get on with playing the music which it does so well.  I wanted to use the S/PDIF method to connect the two as it is a, the simplest and b, hopefully the purest method of hooking the source to the pre-amp (although I stand to be corrected).

As a comparison I have been using the RCA's from the G08 and the CD input on the BP25 this evening and so far no drop outs (typical) if that is any help.

I would appreciate any advice/help with this one as it is starting to get annoying, I don't want to be listening for the gaps in the music all the time.  Maybe James, you could comment if you get a mo' please.

Many thanks in advance for any replies.

Regards,

Barry B

The rest of my system is vertically biamped Lexicon NT 212's (3BST's) driving PMC LB1's.  The interconnects are Chord Chorus and speaker cables Chord Odyssey.

[jethro]

Do you have a regular DVD player with a coax out that you can try with the BP-25DA
to narrow down where the problem is occurring ? If it's still a problem with the
cheap DVD player, then do you have another coax cable that you can try to narrow
things down even further ?

[Barry.B]

Hi Jethro,

Thanks for your quick reply, so far I've been running a JVC XV-N412S DVD player from it's coax S/PDIF digi out into the BP25DA and guess what, after several CD's - no drop out's so far! Obviously I will need to run this over a longer period to be sure (as I said this snag is intermittent so will be "fun" to chase).

When using the analogue RCA output's from the G08 to the CD input on the BP25, the problem again doesn't appear to be present.

Could it be possible that there is a word lock issue between the G08's DAC and the DAC in the BP25 (clutching at straws!!!!) similar to the snags that have been discussed re. SP2 Processor?

Just as an aside, I am surprised at while obviously not in the same league as the G08 CDP in resolution etc, how good a cheap DVD player like the JVC sounds hooked up to my system!! which goes to show how good the Bryston DAC is.  I have read in other forums about an increasing number of people going down this route after experiencing reliability and poor service back up issues with some high end equipment.

Regards,

Barry. B

[brucek]

I wanted to use the S/PDIF method to connect the two as it is a, the simplest and b, hopefully the purest method of hooking the source to the pre-amp (although I stand to be corrected).

Barry,

You have purchased a very expensive CD player that you're not using to its fullest. The dropout problems are an issue to be sure, but why are you not using the CD player as a player.

In a stand alone CD player you use the "same" clock to get the data off the disk as you do to clock the oversampler and clock the D to A converter and clock the sample and hold circuit, upsampler, etc, etc. Now indeed, this clock is divided and multiplied to obtain the correct rate, but the fact is this "synchronous" system is nearly jitter free. The lowly CD player using analog out (if done well) can never be beat in theory by a transport/DAC situation.

It doesn't matter how well you clock the data from the disc and assemble it into the correct format to transmit it out the SPDIF interface, you will have an embedded clock that must be re-created by various means to take care of the D to A process in another external circuit. Errors will be present in this re-created clock no matter what method is used unless you connect a second cable between the transport and DAC with the original clock. This would work beautifully, but the fact is, if you put all this in a single box, we call it a CD player?

The pristine analog out of that CD player requires a proper analog path to the power amp, and you have purchased that path with the BP25. Why not take advantage of it..

brucek

[Barry.B]

Hi Brucek,

Thanks for taking the time to put your view over in a no-nonsense way, it is appreciated. 

I have assembled this system over a number of years by doing the rounds of the dealers in my area, listening to different products and deciding what I wanted and then started on the slow game of saving up for the next item on my list.  Luckily (not for the dealers though although the original intention was to go back to them cash in hand!!!) on each occasion I happened across either an ex-demo unit (the BP25DA - paid the same price as basic pre-amp) or it came up second hand like the NT 212's and the G08 which I bought from a guy who hated digital and was going back to vinyl and let me have it for just over half retail cost.  The LB1's were the result of an insurance claim after favourite eldest son put a football through the bass/mid driver of one of my then current speakers, "sadly" they were out of manufacture and not available. After I nearly wrung his neck I realised he had done me a favour!

This does not detract from the fact that I realise that I possess some serious high end Hi Fi which is in use daily and brings me a lot of pleasure.

I originally had an Arcam based system, CD9 source with 10 integrated amp.  Discovered bi-amping so added a 10P power, and all was rosy in the music dept.  But I had to go looking again and to cut a long story short, discovered Bryston and out went the Arcam amps.  Still looking, fancied a Musical Fidelity Xray V3 player to use as a transport (highly recommeded in reviews) but was demo'd a G08 with a BP25/4Bsst and the rest is history.

I understand your feelings that I am not using the G08 to it's full potential, but I have been in the lucky position of being able to do extended listening trials comparing the two paths of reproduction from the player ie analogue using RCA's and S/PDIF.  To be honest there is but a hairs' difference between the sound using the analogue path from the RCA's and the S/PDIF with Bryston DAC, which is a compliment to both manufacturers.  But this system plays beautiful music in either mode IMHO.
Yes I know I haven't tried using the balanced outputs yet, but will in due course and that may change my opinion.
Personally, I prefer the S/PDIF just a tad more and believe me if the analogue route sounded better that is what I would be using. 

Which is why I have been so frustrated with the dropouts!!!!

Regards,

Barry.B

[Barry.B]

I wanted to use the S/PDIF method to connect the two as it is a, the simplest and b, hopefully the purest method of hooking the source to the pre-amp (although I stand to be corrected).

It doesn't matter how well you clock the data from the disc and assemble it into the correct format to transmit it out the SPDIF interface, you will have an embedded clock that must be re-created by various means to take care of the D to A process in another external circuit. Errors will be present in this re-created clock no matter what method is used unless you connect a second cable between the transport and DAC with the original clock. This would work beautifully, but the fact is, if you put all this in a single box, we call it a CD player?

The pristine analog out of that CD player requires a proper analog path to the power amp, and you have purchased that path with the BP25. Why not take advantage of it..

brucek

Hi brucek,

I'm not sure of the ethics of resurrecting a thread after all this time, but I felt I needed to let you know my recent findings.

I received my BP25 back from my dealer last week after having the mute/normal switch replaced and the DAC checked under warranty.  While I was at the dealer, I asked if he had a pair of balanced cables that I could loan for a week.   Well, he lent me a pair of Atlas Mountain Snow 1 metre cables.

Firstly, what a relief to get the pre-amp back.   You really find out what you are missing when you have to go without the decent quality reproduction in music you are used to for a while.

Secondly, I initially put the system back together how I had originally set it up with the S/PDIF from the CDP feeding the DAC input on the BP25.  I listened for a while then installed the balanced cables between the two.

Obviously there was a jump in volume with the balanced cables.  However, when I compared like for like volume settings (as close as I could get without a dB meter) balanced compared with S/PDIF produced a significantly wider and fuller soundstage.  With S/PDIF, the music is all there but appears more focused centrally between the speakers.  With balanced, as well as the soundstage appearing to extend well past the outer edges of the speakers, what is interesting is the whole effect is more "musical" and "warmer".  The detail is there in abundance and I now understand what is meant by the quiet passages in music seeming "inky black", I am assuming this is the lower noise floor of balanced cables.

So getting to the point of my post, you were correct about using a proper analog path but in my system it means using the balanced connections.  So to get the best out of my system, I now have to start saving for balanced cables to go between the CDP and pre-amp also "Y" balanced cables to go between the pre-amp outputs and my bi-amped power amps!!!(only one left and right balanced output on the BP25)

So thanks for your advice, it's taken me a while but I eventually understand what you meant.

I will still use the S/PDIF for my Squeezebox SB3 as the digital output is far superior than the analog.
Using balanced cables has also eliminated the dropouts so I assume there is a mismatch on the S/PDIF between the G08 and the BP25 probably due to the lack of a separate word clock connection.

Regards,

Barry.B

[brucek]

Sounds good. Actually, I use the balanced cables that Bryston sells and they seem quite good with a decent price.

Yeah, any cheaper device like the squeezebox that would obviously have an inexpensive analog line output section, it would be better to use the dac in the Bryston, but I think you've made the right decision about the disk player.

brucek