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Ah right, no what I meant was *intrinsically* in the voicing of the speakers, not something that's recently gone wrong, and which has been exacerbated by a change of equipment (post Krell failure, maybe?)
Was the issue there before when the Krell was in the system, or at any other time? Can you remember exactly when it happened?:)
Marco.
Without trying to teach granny to suck eggs, the impedance matching is much more critical with high frequency digital signals.Quote:
Originally Posted by Marco
Weirdly I found that the coax input of the Topping D50 wasn't matched at all, a schoolboy error in my book, it was high impedance.
Once I had fitted a 75 ohm terminating resistor it was much more rock solid.
Yes, Alan, I completely agree. That's one of the reasons I use Mark's cables, as they're genuine 75 Ohms, with the supplied Canare plugs.
Marco.
When I had the Krell 50S in the sound was perfection. Since that went faulty I've tried all my other amplifiers including the other Krell and can't get that sound back 100%, it is very close except for the extreme top end not sounding quite right. Using the DAC as a pre-amo helped, the Audiolab transport helped, but it still isn't quite there.Quote:
Originally Posted by Marco
When Alan was round we tried his Neurochrome power amp and his pre-amp and the problem was still there, Which suggests it isn't the amplification. Except that with the Krell 50S in (it will work for a bit before it plays up) the issue pretty much vanished, Alan can testify to all this.
Okies... For me then, that points to the speakers (how the upper-frequency response has been set via the crossover) and/or the characteristics of the tweeters, causing the issue in question, either or both of which the Krell successfully ameliorates.
If you've tried everything else, and the problem still persists, except when the Krell is used, then logic dictates that's likely what it is:)
Marco.
The speakers are getting on for 25 years old so probably not 100%. Even so it seems odd that only one power amp out of half a dozen sounds right with them.
I could put this down to the other amps being old or not that good to begin with, but neither of those applies to Alan's Neurochrome amplifier.
It's really a mystery, if the solution was obvious I would already have solved it!
Really need these Tannoys to arrive, then at least I can rule out the speakers from the equation.
Borrow a fifty quid ProArt from Alan. That'll make you do a double take!Quote:
Originally Posted by Macca
Indeed, especially the latter. Any more news on that - has Shaun been in contact again?:)Quote:
Originally Posted by Macca
Marco.
So you are no longer using the Trompeter cable I made up for you?Quote:
Originally Posted by Marco
The length effect manifests itself if either the output of the CDT and/or the input of the DAC are not matched to 75 Ohm. If there is a serious mismatch, then you need a long cable to increase the triple transit time and thus delay confusion this causes when the digital signal changes from 0 to 1 and vice versa.
RCA phono connectors themselves can never be 75 Ohm impedance, despite what any manufacturer will claim. However the impedance mismatch occurs over a very short length (effectively the length of the mated connector) that it effectively self cancels. That is why SPDIF can 'get away' with using RCA phonos - to do the job properly, Sony and Philips should have specified the use of 75 Ohm BNC connectors. (This is completely different effect to the one of using long cables to increase the triple transit time.)
Not right at this minute, Barry. I wanted to try a full 'loom' of the same (Mark Grant) cables, from source to speakers, which is what's now in place, but I intend on revisiting the Trompeter cable again, now that my ears have been 'attuned' to the sound of the Mark Grants, and see if there is any difference:)Quote:
Originally Posted by Barry
Yup, thanks for that, and noted. It's also the reason why I intend on fitting the digital output of my CD transport, and input of my DAC, with a BNC connector, then also changing the connectors on the coaxial cable, to BNCs. That's a project for later though, as it's not easy accessing the former.Quote:
The length effect manifests itself if either the output of the CDT and/or the input of the DAC are not matched to 75 Ohm. If there is a serious mismatch, then you need a long cable to increase the triple transit time and thus delay confusion this causes when the digital signal changes from 0 to 1 and vice versa.
RCA phono connectors themselves can never be 75 Ohm impedance, despite what any manufacturer will claim. However the impedance mismatch occurs over a very short length (effectively the length of the mated connector) that it effectively self cancels. That is why SPDIF can 'get away' with using RCA phonos - to do the job properly, Sony and Philips should have specified the use of 75 Ohm BNC connectors. (This is completely different effect to the one of using long cables to increase the triple transit time.)
Marco.