TVC Sound

Just to add, I haven't made it my business recently to check out the quality of other £1500 linestages so I can't comment on how well an MFA compares with those. All I can say is that I have listened to better linestages. I don't believe these are necessarily 'additive.' Funnily enough I would say the TVC is definitely 'additive'.

I do quite like the sound of it, mostly when it's playing very loud. I don't think I'd buy one though. I enjoy listening at low levels in the evening when the children are in bed. It doesn't sound right to me when used like that.

I fully agree that digital sources are not necessarily as good as it gets. However they are what many people, including me, listen to some of the time. Performers, microphones, recordings aren't perfect either. We have to work with what there is.

 

I agree it is quite concerning to have ringing like that. But I saw absolutely no difference when I was running it from a 44.1KHz signal gen.. so I really don't feel I need to worry at this point.

When CD is replaced by some super high-res format (more likely MP3 lol!) I will worry about it. Until then, though, the TVC remains superior in my eyes because it doesn't ring and it still has better THD, IMD etc.. (what else does it/should it measure better at, Thorsten?).

I'm not sure what I would do if I had a vinyl system, I'd want to measure the output of a square wave from a record and see how it reacts.

Anybody got a square-wave record? hmmm...

I guess I’d have to demo it against other pre-amps and see which sounded less coloured. Maybe Nick should have a listen to some more high-end active pre-amps from his TT. For CD though, it seem pretty obvious which is more accurate if indeed the passive does have better THD and IMD and other things.

 

That is utter nonsense. It is perfectly possible to make a well engineered amplifier that reproduces a 4KHz square wave without ringing.

 

How come?

On a side note, it is nice to see some objectivism from ZeroGain!

 

Not a true square wave I am afraid murray - no amp can have infinite bandwidth. I agree active pres can have much greater bandwidth than a TVC however bandwidth isnt everything and the main value of high bandwidth and slew in an active device is to reduce the ill effects of feedback. TVCs dont employ feedback so it isnt necessary. They appear to be good out to 100 khz or so and thats good enough for me.

I do plan to check against other units if people want to bring them (and phono stages) along.

 

More like just over 40KHz it seems.

 

Ripples aren't ringing.

The visible effect of the distortion of the square wave by the bandwidth limiting will depend on the phase characteristics of the filter, but the result will not be square.

It implies a lack of bandwidth control, an audio amp should amplify audio and not radio transmissions. Power amps especially can get upset, whatever their topology. It's better to manage the bandwidth by design than leave it to chance or the loudspeakers.

Paul

 

So just for clarification, has Simon got the dodgy Mk1 transformers or was that all disinformation from the manufacturer in the light of less than favourabler measurements?

 

Huh? I have the most recent MK.III and the measurements do indeed seem a bit better. Bare in mind that my signal gen was not as good in the first place.

 

What is the TX-102 doing then? It does seem to start and deteriorate over time so I guess it is actual ringing?

 

BBV,

a couple of questions.

Why keep referring to the Vibe? Is that some sort of benchmark for you?

Out of interest, what power amp and speakers are you using?

 

It was mentioned by several people earlier in this thread or in another thread (I cant remember which) as showing the tvc a clean pair of heels when it comes to accuracy.

I am using a PMC MB2-XBD-Active system.

 

So, Bryston electronics and the full PMC set.
Your priorities when reproducing music would seem to be somewhat different to mine and I can understand better now why what I hear as the shortcomings of the TVC might not be of relevance to you.

We can agree to differ!

 

No it wasn't. I suggested it might be on your list of active preamps to try, that's all. You claim you've already heard it, but presumably not a home dem? In any event, I do think you should try a few good active preamps at home as a comparison to the TVC. Give Walrus a call, they'll lend you a few. Your insistence that you have the best is somewhat undermined by the fact that you haven't done many comparisons. I remember you claiming on PFM that the White Noise DIY preamp you used to have was far superior to "any" (your word) commercial preamps, but you seem to have finally realised that perhaps that wasn't the case. Perhaps you may discover the same thing about the TVC too.

-- Ian

 

BBV,
As you seem to be enjoying the bel canto dac2, why not try a bel canto pre?

 

Which perceived short comings of the TVC would those be? What do you think you can hear. It is of course a familiar ploy to ask what kit someone is using and then blame "a lack of resolution" in their system in a knowing manner when it is revealed. It is of course complete nonsense. The fault could lie in your system as much as mine.

The BC dac is quite good but not outstanding. I bought it second hand for very little - until I can sort out something more permanant. Not as good as my PT de capo was for sure. If someone brings a BC pre (or any other pre or phono) along I will take a listen.

SSB - I was referring to SMs post as well as yours. The DIY WNA preamp was pretty good - as was the phono - both beat the corresponding TEAD units. However the TVC is better. As is the borbely. Most likely due to the absence of any of the opamps that both WNA and TEAD utilise. I loaded the WNA with the same opamps as the groove and they sounded pretty similiar, with quite a pronounced character. I have heard quite a few different pres and phonos over the years

 

Measured Squarewave response of the MKIII

Folks,

A friend of mine who owns a better digital camera and the Velleman 'scope with backlit screen kindly took these.... Conditions are 5V in, 10K load.

Generator output:



Output from TX-102 @ 0db:



Output from TX-102 @ -9db:



Output from TX-102 @ -20db:



Output from TX-102 @ -30db:



Output from TX-102 @ -38db:



Not much comment needed, a little rining, more at lower steps but nothing I'd loose sleep about (you should see the ringing in the compression drivers so beloved by some here and even worse in metal dome tweeters).

Simon's measurements show a lot more ringing PRECISELY because he did not use a true squarewave, but a squarewave overlaid with some additional junk (not exactly a single one sinewave either) from the digital filter, with a frequency fairly close to the resonance mode.

So, as observed, Mr. Jones aparently has an older revision, as what he has in hand appears an early one-off silver version that was custom made, NOT the actual released Silver Preamplifier. What is released and current production measures like above. one might wish to see a little less rininging, but what is there is fairly well damped and should not be cause for excessive alarm.

That said, if Speakers can have the square wave responses they have and nevertheless sound good, then I must question even for the much worse measuring MKI TX-102 any causal link between percieved sonic issues and the measured performance with squarewaves.

As a parting shot and to put into context the issues of ringing, here the impulse response of a rather highly reviewed and priced Speaker:



A 4KHz squarewave in this context would have a period of 0.25mS so each halve cycle (square) would be 0.125mS or around 1/10th of the ringing duration exhibited by this speaker.

Ciao T

 

According to some people I've talked to, wavelet analysis should be a more reliable indicator of amp quality than square wave testing. Not that I have a good undrstanding of this, of course, I'm just passing on a couple of comments.

It would also be interesting to see the spectral content of the distortion (even order, uneven order, falling distortion with order?).

 

I'd far rather listen to music via an amp than watch it generate sine waves. Bright shiny LEDs and glowing valves add to the aesthetic appeal of course.

 

BBV, so long as you consider this a competition, your system will be hamstrung.

I can understand Thorsten leaping to the unit's defence, simply because he has a financial/professional interest in the products mentioned.

But you simply seem to see your hifi as a weapon in some internet based virtual competition to the exclusion of all others. That is sad IMO and I think Ian's advice is the soundest thing I have seen on this thread.