audio-talk

Excellent decorative symmetry .

karatestu wrote: ↑Mon Nov 07, 2022 5:37 am Looks easy on the eye Steve. I expect it's kind to the ears too.

Aye, it’s certainly easy on the ear. It’s a lovely little system.

Happy….as a pig in the proverbial… that’s me (pan preceding phrase right then centre then left. Follow with maniacal laughter from hard left.)

Daniel Quinn wrote: ↑Mon Nov 07, 2022 8:38 am Excellent decorative symmetry .

Yep, the missus is well pleased with the looks and the sound.

Excellent, does look really good!

Mike H wrote: ↑Mon Nov 07, 2022 5:01 pm Excellent, does look really good!

Thanks Mike.
Finally today, I got around to fitting the spikes to the speaker bases and levelling them up properly.

Since I started all that DIY stuff back in 2005, I’ve never really bothered about spikes and cables, but fitting the spikes to the Mission 773s brought about some nice little improvements to the overall sound. Biggest gain was the bass. Our Ant had noticed a bit of a thrum on certain notes and had pointed to the ports joining in as a possible cause, but it turned out not to be the case. It had actually been a suspended floor resonance. Coupling the speaker cabs to the floor at only the spike points rather than via the entire surface area of the cabinet bases, solved the issue.

I reinstalled the NVA phono boards back into the amp, a couple of days ago, so now the TT can simply be plugged into the back meaning, less boxes and one less cable and. I’m all for that these days. I moved the records upstairs into the study and placed the TT where the amp had been. The full system is now back together:

Having looked into this , the nva phono amp uses op amps much the same as the vast majority of phono stages . It has four however, which I think is unique . Further, each can be subject to its own power supply which I think explains the difference the power supply makes. The bigger and separate the better
.
I can think of no other phono amp except the tricord which trumpets power supply , but that only as 2.

Personally I am liking a lot discrete stages.

It has four however, which I think is unique

Four single op amps may be uncommon nowadays, however two dual op amps is functionally equivalent and it likely to be much more common. The cheap MM phono I make has two dual op amps and two singles (the singles act as a DC servo).

Cressy Snr wrote: ↑Sat Nov 12, 2022 10:28 am The full system is now back together:

Looking good Steve. Did you have any joy repairing the vinyl on the Missions?

Cressy Snr wrote: ↑Wed Nov 09, 2022 10:30 pm ...but fitting the spikes to the Mission 773s brought about some nice little improvements to the overall sound.

It doesn't look as though you're using the feet that were in the box I gave you - the speakers were much more stable when fitted.

Ray P wrote: ↑Sun Nov 13, 2022 3:31 pm It doesn't look as though you're using the feet that were in the box I gave you - the speakers were much more stable when fitted.

That job is on the list for next week. I need to get some shorter M6 bolts than the ones I have.

Ray P wrote: ↑Sun Nov 13, 2022 3:23 pm Looking good Steve. Did you have any joy repairing the vinyl on the Missions?

Another job for next week. I’ve lifted the damaged areas with a scalpel, straightened out the torn shreds and re-glued the damaged vinyl down. I now need to match the colour and stipple over the joins.

Cressy Snr wrote: ↑Sun Nov 13, 2022 4:30 pm

Ray P wrote: ↑Sun Nov 13, 2022 3:31 pm It doesn't look as though you're using the feet that were in the box I gave you - the speakers were much more stable when fitted.

That job is on the list for next week. I need to get some shorter M6 bolts than the ones I have.

Hacksaw

Tried the outriggers today but I didn’t like the effect they had on the sound. It was hard to pin down what it was but it bothered me, so they were removed and the status quo restored.

Fecking spikes gashed my left wrist though. The perils of commercial speakers.
I’m leaving well alone now.

Been having a nice time with the RD/STS amplifier, scope and sig gen this weekend just gone.

I have, by playing with the NFb levels and adding Zobel/ inductor compensation networks to the output stage, managed, quite nicely to close the gap with the valve amp. But there was still some residual "solid stateness" going on. To cut a long story short, I did some further work on the NFb, piggy-backing different resistors onto the 18K stock setup, measuring and listening carefully to the results. I'm not usually one for this kind of fine tuning approach; I don't normally have the patience. However taking a leaf out of Mark Chris and Colin's book I shut up and got on with it. The upshot, is that an exact doubling of the feedback level has brought about a major improvement. It doesn't sound like the same amplifier any more. Running into the Mission floor standers, the bass seems to have found an extra octave of downward extension, whilst at the same time tightening up substantially and evening out across the low range.

I had thought that a peak occurring in some walking bass lines where one note stood out as the player tracked up and down the fretboard was a room mode being set off by the Missions' extra extension, except it wasn't. Kick drum also tightened and opened out so that it was easy to hear the characteristics of different tunings/degrees of damping being applied rather than hearing the same thud whatever the recording. Tom and snare strikes now rattle out of the soundstage like they should. Although the acoustic power is not to "drum kit in the living room" standard, drums do sound more believable now. The low register of piano is also rich, resonant and beautifully controlled, so I reckon the bass end is now better sorted than before.

Transients are faster with lots of small percussive details much more evident than previous. In fact, what I've often perceived as a frustrating lack of treble detail or extension with a lot of my projects, is simply down to not being willing in the past, to sweat the small stuff. It is also a long time since I've heard instruments or performers occupying their own acoustic areas between the speakers, with nothing bleeding into anyone else's space. Hmmm.

Nice work !