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DIY time aligning circuit defined?

L

Linnik

Flat Earth - Source First
I have been wondering why nobody has defined the Naim time aligning circuitry here?

It would be nice to mod the older preamps like 42.5, 32.5 and 62 for time aligned filtration.

The history of commenting it in DIY circles: Les Wolstenholme has written his thesis that time alignment by Naim means mixing some trebles between the channels with revised phase. While Andrew L. Weekes has confirmed this not being true but named time aligning being rather higher quality high freq. roll off filtering. Step ahead from the older similar circuitry. This being exactly how Naim themselves have described it to be.

Would someone skilled enough please define the circuitry layout?

Could it be easily planted to the older boards with some extra wiring or a small assisting board?

This would be most interesting for many of us modders, I am sure.

Oz
 
Why would you want an extra filter Oz..?? Extra circuits only serve to detract information from the signal and add unwanted noise. The so called time aligned filter does both and although Naim owners seem to admire the fuzzy, veiled effects this filter imparts, I feel the overall sound is better off without it.
 
And then you say you would be happy if you knew how Naim make that marvellous leading edge, Les!

People (i.e. Andy) tend to say Naim power amps sound much better when the extremes of the freq range is cut out in the preamp or in the input of the power amp. Outside the hearing area. With you and me, Les, (and with certain Mr. Parry too, your model) it could be quite narrow band necessary to be left, I guess... Our age takes part here. Real time alignment, you could say perhaps. ;)

Of course we can say that Naim power amps a peculiar. But isn't it quite obvious that all power amps work better if the extremes with all the possible nasties (no music signal) are filtered out from the input signal?

Oz


THANKS MUS!!!
 
My earliest experiments in this area involved by-passing the buffer boards in my 42.5. - I figured they served no useful purpose, so long as the source component could drive the volume pot. I have to say, I was surprised to find the results didn't stack up as I expected; There was more detail yes, but the music seemed to be less cohesive, less involving.

This led me down the path of keeping the buffers (with their simple RC input filters), and trying a new tack of improving the power supplies to each stage, using local regulation. This produced better results, but still fell short on the detail front, with the sound always appearing a little too veiled for my liking.

Eventually, a move to the 102 (in standard form, with its TA filters) brought me some way closer to the 'transparent' sound I was after. I knew local regulation would likely further improve the sound, so I modded the 102. Eventually, it ended up with local reg's and a much modified hicap, decked out with six ALW SR's.

The end result is a preamp that seems to connect the listener directly to the source, with no hint of smearing or loss of information, and with the music presented in a cohesive and accessable way.

The point I'm making, is that (IMO) the absolute best results are had by using a TA equipped preamp, with all stages intact, but with a much more sophisticated power supply to allow each stage to work to the best of its ability.

The NAC72 729 TA buffer boards can still (AFAIK) be bought separately, for those interested in trying them.

Mr Tibbs
 
I have had quite exactly the same experience in passing the buffer amp than Mr. Tibbs here.

Passing the buffer had to be done as it was advised by Les and Neil McBride by the obvious assumption the less the components, less the noise and loss of information.

But it did not much make anything better. Taking them back in the circuit felt better.

And afterwards, thinking the original principle why buffer was there made it more clear to understand why to keep em, too.

Yes, you can buy the boards of 72 but as doing DIY it would be more appropriate to mod the old buffer for the TA way. Or is it so much different that there is no no situation there?

The schema MUS sent might deserve more intense reading...

Oz
 
Mr Tibbs:
"Eventually, it ended up with local reg's and a much modified hicap, decked out with six ALW SR's."
Click to expand...
Hi Mr Tibbs
In the last few days I have been reading your posts with great interest, especially the "preamp fun and games" one.
As I am now in the stage of modding 32.5/Hi/140, I am really curious: how did you manage to push six SR boards into the Hi-Cap?
I am also wondering about the local regs in the 102 - where did you locate them? did you use a ready-made PCB or just stitch-wiring?
Thanks, Yair
 
The question of TA boards or not is avery interesting one.

My preamp has them removed ( along with almost everything else) and it does not suffer from the problems reported above. However, I use an APX2 (2 transformers) to power the pre-amp and if memory serves me corrctly CED posted that his preamp only worked well with the TA boards removed if seperate windings or transformers were used to power the gain boards. so I think I stumbled on a successful formula without knowing why.

I also altered my APX2 earthing to provide seperate earth returns as suggested by Mr Tibbs, and this is a no-brainer, superb!

Regards,

Ian
 
"Yes, you can buy the boards of 72 but as doing DIY it would be more appropriate to mod the old buffer for the TA way. Or is it so much different that there is no no situation there?"

The 729 boards aren't that expensive AFAIK - certainly not expensive enough to make DIY 729's a worthwhile exercise.

"I am really curious: how did you manage to push six SR boards into the Hi-Cap?"

This is one of those times when a picture is worth a thousand words! Basically, I made up an 'E' shaped copper heatsink/mounting plate which stands vertically in the hicap near the outside edge, opposite the capacitors. The SR's are fixed to this in two columns of three SR's (three in each half of the E shape). Get the idea?

"I am also wondering about the local regs in the 102 - where did you locate them? did you use a ready-made PCB or just stitch-wiring?"

The LT reg's are fitted on some small home-made pcb's, with the reg's mounted under the 102 pcb, at each stage.

"The question of TA boards or not is avery interesting one. My preamp has them removed ( along with almost everything else) and it does not suffer from the problems reported above. "

I think it's more a matter of personal preference than anything else. That's the beauty of DIY - you can decide what works best for you.

"I also altered my APX2 earthing to provide seperate earth returns as suggested by Mr Tibbs, and this is a no-brainer, superb!"

I'm glad you think it's a no-brainer and I hope others try it too :)

Mr Tibbs
 
"Pretty please!"

Hmm... it lives under the floor y'see, so it's not that easy :rolleyes:

Sometime this winter I plan to dig it up and add a few minor refinements, so I'll do a proper thread with pic's then.

Mr Tibbs
 
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