Around the Blog-Fire

Regarding the leedh software volume control, theres simply no way around the math. Whenever you digitise signal level into a number of discrete steps, be iy in 16, 24, 32, 64 or 128 bit, there is rounding error involved. Sure go to enough bits and the steps and the loss becomes minuscule, but it's never lossless, not mathematically speaking.

Deaf rasta spider lol

I must admit that went through my mind as well, class.

Jah is with them.

Lose a little body?

Testing the sub,



Though to be honest the bass isn't that low on Shabba, only about 80Hz.

Have to find something a lot lower, I know 'Hey now' by London Grammar, that's got 32Hz bass ......BASS ......BASS .....BASS!

That is hiding the Milli Vanilli

I know theres loads of very clever people out there, but the maths is immutable, you can make all sorts of clever guesses and interpolate to ones heart content, but it's still guesswork.

And that's why there's no public data on the method, because it wouldn't stand up to scrutiny. One simply cant have a 'lossles'digital volume control, the bit loss is always proportional to word length and level change.

Don't talk cr@p. I like Maxi Priest .............

Hahaha

Next project, re-boxing a valve buffer stage.
This was boxed up previously as the 'Mad Cow Buffer' but the C core transformer hummed so that and the RCA sockets were used on other things.




A smaller transformer was sourced from China, the original C core was over specified anyway. Trannie and on/off switch:




The case is one that has been re-purposed (bit of a fannie expression really, it's like Merc dealers saying 'pre-owned'  ), so it's off to the workbench.

Small form

Like it

You sound very happy with the OCC cable? Is this the graphene stuff that you used?

A while back I bought a Lounge Audio LCR Mk3 phono stage, basically to scratch an itch to hear/have an LCR based phono stage.

The only other one I have heard is the Music First LCR designed by Nick Gorham and that is both sublime and exceedingly expensive.
However when I tried out the Lounge Audio it just wasn't very good. In fact one of the worst 'out of the box' phono stages I have tried.




The bass was distinctive in that there wasn't much of it plus there was a measure of distortion coming through. If I had just bought this to use as was I would not have been happy.

Fortunately I can alter things electronic, so I searched for a schematic without result. Back to the 'whip the board out and trace the circuit' principle, takes a little while though.
What I found staggered me  .

Although the discrete LCR network was ostensibly good, designed around the traditional 600 ohm impedance, the drive to it was through a very low value capacitor hence there was a bass drop off to the response. To compensate for this the designer had incorporated a bass boost circuit in the first op-amp stage, wtf?

The first stage of a phono stage definitely doesn't want extra bass boost. Once I had removed the boost and fitted a much larger (x50) coupling capacitor things got rather better.
However there was still some distortion which I tracked down to the inclusion of current sinks on the op-amp outputs. These were supposedly to make the op-amps work in a fully Class A fashion, but the sound was definitely clearer once these were removed.

The overall response was still bass light and I discovered that the supposedly 1.8 Henry choke in the LCR network was in fact a lot closer to 1.2 Henries, not good. Once I have re-engineered the LCR values to level out the response as much as I could the stage performed a lot lot better than originally. The LCR network wasn't a fixed 600 ohms over the full frequency range anymore, but being driven from the low impedance of an op-amp was an acceptable compromise.

The tale ends on a high note, I have just sold this and gave it a quick test before packing just to make sure it was OK.
The whole audio system has been getting more transparent of late and the reworked Lounge Audio LCR was exceedingly good.