[ACMP investiupgradifications] All things PREAMP

[okgb]

maybe the thinness was due to ringing ?
thanks for the advice
yeah how far do you go before just getting a better kit
anyone have an update , chance ever make good on anything ?

 

[redddog]

Thus far, no one has made good on anything.

I think the best chance for that exists through Terry M. but even with that operation, we are still getting the "soon...very soon" time-frame.

In my opinion, we are still in the "never gonna happen" zone with Mr. Hogan.

 

[tommypiper]

yeah how far do you go before just getting a better kit

Here's my approach.  I plan to do the standard fixes Steve has outlined so far, more or less, then listen to it.  If it's OK, I'm done.  If I feel it needs more work I'll put in a Cinemag or Lundahl input transformer and a Lundahl Neve-clone output transformer, and possibly a new PSU transformer or whole new PSU.  Because, assuming the transistors and caps will all be good quality at that point by following Steve's recipe and my own additional changes, if any, then the transformers are the next, and only, weak link left in the audio chain.  It would make sense to change them.

IMO, it makes no sense to construct elaborate RC networks and play games trying to get the cheapest of the cheap stock transformers in this unit working halfway decently.  You either accept them for what they are, with any quick fix, or swap them out.  This is why I feel Steve is wasting his and our time on them.  I even wonder if Steve is stretching the analysis to the limits of perfection just to justify his continued delay... but let's not go there.   :-\

 

[rodabod]

Overall, the transformers aren't bad. I fully modded one unit and compared it to stock; the difference is not night and day.

Through doing this, you will realise that the Neve sound comes a lot from the design, especially when it starts to get gritty/crunchy.

 

[rodabod]

maybe the thinness was due to ringing ?

That did cross my mind, but in this case, I think no.

 

[D3R1D3X]

What MOD would you guys suggest for the EQ-part of the '73-s?

 

[okgb]

The original poster should sum it up on the firdt page , haven't seen him around for a while
clint rubber ????
otherwise you're going to have to go through 48 pages , depending on your problems
transistor changes

 

[D3R1D3X]

Yup, that would be hell of a lot to read...

I'm pretty much satisfied with the preamp part of the '73-s, it's just the eqs I found myself omitting, because they kind of mess up the sound. Is it me, or did anyone else notice this?

 

[crazydoc]

Yup, that would be hell of a lot to read...

I'm pretty much satisfied with the preamp part of the '73-s, it's just the eqs I found myself omitting, because they kind of mess up the sound. Is it me, or did anyone else notice this?

The eq might have some spurious induced hum at some settings. I fixed mine by mu-metal shielding the inductors and the power transformer.

 

[D3R1D3X]

Yup, that would be hell of a lot to read...

I'm pretty much satisfied with the preamp part of the '73-s, it's just the eqs I found myself omitting, because they kind of mess up the sound. Is it me, or did anyone else notice this?

The eq might have some spurious induced hum at some settings. I fixed mine by mu-metal shielding the inductors and the power transformer.

Thanks CrazyDoc (are you really a doctor? )!

Did you use a foil, or plates? Did it solve all the "weirdness" comeing with the eq?

 

[crazydoc]

Thanks CrazyDoc (are you really a doctor? )!

Did you use a foil, or plates? Did it solve all the "weirdness" comeing with the eq?

Yes, I am.

I used .025" thickness high permeability plate, in double thickness around the toroid (separated by a corrugated cardboard spacer), and single around the inductors, and it solved all the induced noise issues in my 73.

 

[diyfanatic]

I've used this with good result (on the trafo and the inductors)
http://www.don-audio.com/trafo-shielding

with the transistor change I'm pretty happy with the Chineve!!

 

[D3R1D3X]

Thanks CrazyDoc (are you really a doctor? )!

Did you use a foil, or plates? Did it solve all the "weirdness" comeing with the eq?

Yes, I am.

I used .025" thickness high permeability plate, in double thickness around the toroid (separated by a corrugated cardboard spacer), and single around the inductors, and it solved all the induced noise issues in my 73.

This means, we are colleagues

Thanks for the tips guys, I'll try them.

 

[clintrubber]

The original poster should sum it up on the firdt page , haven't seen him around for a while
clint rubber ????
otherwise you're going to have to go through 48 pages , depending on your problems
transistor changes

Hi Greg,

I'm sorry, no time for that here anytime soon I'm afraid.

I'm also glad I don't see it as the role of the OP of this thread, lucky me 

IIRC some guys had already made some kind of intermediate summary (also one from you IIRC) and without having read the most recent stuff I figure those shortlists still cover most of the essentials.

IIRC (#3...), the most important one was to replace several driver-BJTs (>power), after that swap for some Ge-diodes & lower-noise BJTs, perhaps tackle the gainswitch-click etc, shield some coils... all these 'lesser ones' don't come to mind right away, but as I understood it it's entering the realm of diminishing returns...

Cheers all

 

[okgb]

I mean it in the way that only the op can modify the first page
which is easiest for people to reference
many of the meta's are not kept up either
and many clogged with me too or thanks allot

 

[clintrubber]

Hi Greg,

In case my reaction sounded a bit harsh please accept my apologies, wasn't meant that way.

I'm of course more than willing to paste some stuff into the first message, just let me know (anyone).

All the best,

  Peter
 

I mean it in the way that only the op can modify the first page
which is easiest for people to reference
many of the meta's are not kept up either
and many clogged with me too or thanks allot

 

[mitsos]

That will definitely be one looooong post.  : 

Maybe we should start a wiki? Then you just need the link in the first post? 

 

[clintrubber]

Maybe we should start a wiki? Then you just need the link in the first post? 

ImHo, let's not overdo things but simply get these preamps on the road by swapping those mentioned BJTs.

That definitely won't be all they need, but then at least your using them.
And perhaps more later.

The alternative is that we contemplate about all required & not so required modifications,
write a fifty-page thread about them and as a consequence it might have beeen better that these preamps
were not using up any components at all since they'll never see any signal (since our TNC-mics
are on the bench for life as well  )

I sure appreciate the various & thorough contributed observations and might one day implement
several of them in addition, but the request for the to-do list has popped up before in this thread while there's
actually not that much to it, at least not as much as the length of this thread might suggest.

I'm of course still happy to insert a summary on the first page, just let me know. 

Bye all,

  Peter

 

[rodabod]

There's quite a lot of drivel in this thread, including stuff which probably should have been kept in a Whitemarket thread (ie. Steve Hogan's business).

Anyway, if you want to fix your preamps, read the thread, you'll learn something, and you should be able to get them running fairly well.

 

[okgb]

I started  [ the first half ] to complile the info
someone in the past said they would host  it , but
even at that it needed allot of editing and references
to other posts , [ waay to big for a single post  ]
I'll try to dig up some of the info , being concise
and mail it to Clint but perhaps point form leaving out
subjective comments

It takes days of reading for some of these threads now ,
i feel responsible for the great river thread and try to keep
[ it's settled down now ] relavent info on P1  but of course
many more issues on NON working chineve pres