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Time Aligned filter upgrade, Really Good!

Back from holidays, the first thing I ve done today was to stuff with trannies,oscons and resistors a DIY time alignement board (for my 32,5) I got from a fellow member of this forum. I used both the Acoustica pics and my original boards in my 72 (fairly late model I guess). Now my question id where's the R4 with 62k to be replaced? I only found 46K already in place but not a trace of 62k.
Can anyone update me on this?
Cheers
 
You need to go back to the first post and click the link to the circuit diagram, R4 is top left.

Please check but I believe the 72 has a 47k [not 46K] already.

Please see my [invisible] post above where, I can only guess by the silence, it has made people re-read and edit all their previous postings on the subject of justifying a 102 over a 72 by saying that the remote control is the only difference. I jest, of course ;-)
 
Thanks Eric. It certainly is 47k. I quoted from memory. Now I want to say how happy I am with my DIY time-aligned boards in my 32.5. stuffed with BC550/60 in lieau of the unobtainable ZTXT 384/214. They are sourced with R4 @47k. Do they fare better here than the original ZTX's? If so, would it be worth replacing those in my original boards in my 72?
Cheers wise men
 
Hi!

Just came back and saw the thread progress, thanks to Teddy for describing the technical details. I am also very glad to hear I wasn't just experiencing some serious placebo...

Today I also compared my 102 (mods: MMK feedbacks with improved grounding, oscon decouplers, TA-filter ala 82) to a friends MMK feedback modded 82; it was a dead heat. I slightly preferred my 102, but that might very well have been patriotic mindgames. However, after inserting some Oscons into his 82 it went flying. The most effortless and powerful music I have ever heard. Certainly inspires me to continue modding though!

I wonder what the remaining differences might be contributed to, do they all share the same buffer and gainstage? What else can account for the difference, different powersupply structures (the 102 shares at least one rail with some of the switching and led where the 82 don't)?

Cheers /Magnus
 
(the 102 shares at least one rail with some of the switching and led where the 82 don't)?
Click to expand...

Yes, but it's easy to change that - and worth it. Any extra load on the audio PS will degrade it, even the front panel logo.

Mr Tibbs
 
AFAIK the 82 ground plane is different too. The control circuitry and the audio circuitry don't share the same ground while on the 102 they do. I've tried to separate the ground planes on the 102 too but failed in doing it. The circuit is designed in such a way that one circuit needs to reference the other for the delay relay. I don't know how it's done onn the 82, and I know that on the 282 its yet another story.

BTW, I'd be interested to know which resistor values are used on the NAC202. Anyone here can report?

Teddy
 
I've tried to separate the ground planes on the 102 too but failed in doing it. The circuit is designed in such a way that one circuit needs to reference the other for the delay relay.
Click to expand...

Teddy, I had a look at that as well and came to the same conclusion. I don't think it's causing much of a problem though.

Mr Tibbs
 
Agent_Cooper79 said:
Hi!

Just came back and saw the thread progress, thanks to Teddy for describing the technical details. I am also very glad to hear I wasn't just experiencing some serious placebo...

Today I also compared my 102 (mods: MMK feedbacks with improved grounding, oscon decouplers, TA-filter ala 82) to a friends MMK feedback modded 82; it was a dead heat. I slightly preferred my 102, but that might very well have been patriotic mindgames. However, after inserting some Oscons into his 82 it went flying. The most effortless and powerful music I have ever heard. Certainly inspires me to continue modding though!

I wonder what the remaining differences might be contributed to, do they all share the same buffer and gainstage? What else can account for the difference, different powersupply structures (the 102 shares at least one rail with some of the switching and led where the 82 don't)?

Cheers /Magnus
Click to expand...

Hi All!

First of all:
Magnus , many thanks again for your guidance, knowledge and input for the mods implemented in my 82. After the Oscons....Wow!
This is serious stuff indeed.


Now to The 102. After Magnus latest mod his 102 is as good or even better than my 82 with the MMK mod.
The steps that it took with this last mod remarkable.

As somekind of benchmark:
What was used in this audition excluding the preamps is what I have at home:
CDS2, early this year serviced incl. new transport by authorised service in Gothenburg.
Black burndy
Standard Lavender snaic
One Hicap prod. 2003 with black snaic.
Napsc 2.
NAP 135 fully serviced in 2005 , Naim Salisbury.
All that on Mana amp stand with Base Technology isolation platforms for the CDS2 and Pre amp.
Naca 5
Speakers is Totem Mani 2, blu-tacked on M-stands,non spiked, instead I´m using Kuntze no-vibra feet.


Magnus, I will with anticipation follow the progress with your 102. There is most certainly more to come.

Best regards
 
Magnus and all

I feel I need to write a post scriptum to my latest post.
The last sentece in me using the word anticipation, is inapropiate. I was trying to make a joke, but it was badly put. Sorry.

What I really want to say is that I am delighted to follow the development that this 102 has undergone in Magnus hands and are looking forward to hear what else can be unfold in performance from this preamp.

I have the thought of designers deliberately designing the 102 to underperform towards a 82 . Otoh what can be retrieved from a 82 with the mods that we have done on mine is also
puzzling me and a very surpising to say the least, in positive way I may add.
 
Hi Gunnar,

nice to see you here on Pinkfish! I look forward to hearing your 82 again soon after the latest additions have settled in, from cold it was really sweet!

Cheers /Magnus
 
Agent_Cooper79 said:
Hi Gunnar,

nice to see you here on Pinkfish! I look forward to hearing your 82 again soon after the latest additions have settled in, from cold it was really sweet!

Cheers /Magnus
Click to expand...

Yes I would like you come over and evaluate this mod. It has developed to an extent that I never could have dreamed to hope for. Well do that as soon as possible.
Best regards
 
Gunnar & Magnus,

Thanks for your interesting reports. It is likely that some of the improvement on the 82 when Oscons were fitted came from the fact that the original caps were getting old (8+ years). If so, just replacing with new original factory caps would have given an improvement. But having used oscons in 2 pre-amps, they are certainly good news in most cases (power decoupling, but not signal path).

Jo
 
Jo Sharp said:
Gunnar & Magnus,

Thanks for your interesting reports. It is likely that some of the improvement on the 82 when Oscons were fitted came from the fact that the original caps were getting old (8+ years). If so, just replacing with new original factory caps would have given an improvement. But having used oscons in 2 pre-amps, they are certainly good news in most cases (power decoupling, but not signal path).

Jo
Click to expand...

Jo
I had the same thoughts when ( regarding ageing caps ) we first plugged it in after replacing the original caps with Oscons. Perhaps they were too long in the tooth?
Now that the pre amp has burned in after a week, there is no doubt that this is something else, to say the least.
This is so bloody good that I almost hesitate to use this kind of superlatives as it almost seems like I´m exaggerating what this mod does.

One other thing, I´ve never heard my 82 respond to the addition of another of my two hicaps ( when I after the test Magnus and I had,connected the other hicap that I normally use)

This mod I highly recommend.
There is an improvement in all areas. This is a big jump.
What it does more technically in the the preamp I´m sure Magnus can explain as I don´t have the insight in this.

Best regards
Gunnar
 
In my NAC42 gain stages I've used LesW's mod for the current source supplies - 62k replaced by 4k7, 100uF to ground, then 56k to TR3 & 4 (excellent in itself). With what value(s) should I replace the 4k7 or 56k resistors ? How about 43k instead of 56k ?
 
That sounds about right, although I think it was Teddy who tried this mod on the gainstages and reported very little effect. Somehow it seemes to make a bigger impression if applied to the TA-filter.

But please tell how you get on, I am very curious about this and haven't had time to try that yet.

/Magnus
 
Hi /Magnus and anyone else who's interested,
Not having any decent 43k resistors I used 47k MRS25s. The improvement is very noticeable with those - more vigour, space, air, tonal colour, detail, dynamic range ... this on two 42s modded according to LesW, Ced, Neil McBride and Pink Fish precepts (in no order of importance).
If anyone has a couple of spare 43k RN60s I want them ...
 
This divider cuts the PSU rail noise into the biasing of the current source, but it doesn't affect the actual drain current setting. So the precise resistor values don't matter, you can split that 62k up using whatever reasonable values you have to hand. Even 10k/10K would work just fine, in fact it would ensure lots of base current drive for the current source transistor.
 
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