Mo Metal

Holla atcha boy!
Wadawannaknow?

:shock:

Are you taking those apart?

:shock:

which one smells the best?

my carnhill smelled pretty good fresh out of the box.

dave

'cueing Jaws theme'

it's like a iron pie fair

[quote author="CJ"]Holla atcha boy!
Wadawannaknow?

[/quote]

Oh Oh....yes, I got a question!

uhm...... when you finished building you fairchridken compressor clone, will you sell your other one in your garage scrap metal sale for $10 per kg? :razz:

I'll even take away the pultec off your hand at NO EXTRA charge!!! :shock:

Weight:
Marinair 1: 0.997 lbs
Marinair 2: 1.0265 lbs
Marinair 3: 1.0275 lbs
Carnhill Re-issue: 1.0145 lbs
Sowter: 1.1735 lbs

Lam Stack:
1: 0.7765
2: 0.7855
3: 0.7740
4: 0.774
5: 01.0035


You guys crack me up!


Iny Meanie Miny Mo Catch a tranny by the toe
My mom says to pick the very first one.
Ican only hack one . The rest are on loan.
Early Marinair gets torched. But I still have to sweep,b-h,inductance,dcr, mag current, phase shift and all that, but pretty soon.
From just looking, I can guess that the winding structure is pri-sec-sec-pri.

Stay tuned......

[quote author="CJ"]

[/quote]


OK OK, easy now CJ....... I was just kiddin... :green:

GIMME GIMME GIMME

GIMME GIMME GIMME

CJ-

especially interested to see what 150-400 HZ is doing with those. The sowter gets praised (or criticized) for being clearer sounding (imo a good thing on a neve) but it would be nice to see what the scope says.

dave

Yes, Dave, that is what I have been told.
Look at the stack height. 25 percent Mo Metal.

I should mention that xfmr #1 is a Marinair LO2567 which is an ungapped transformer.
The other four transformers are gapped.
The two gapped Marinair's are LO 1166A's
The Sowter is an 8751

Here is inductance and dcr.

#1 LO 2567
Pri: 1580 mH 13.2 ohms
Sec: (only pins 5 and 6 have continuity) 400 mH 19.2 ohms

#2 LO 1166
Pri: 833 mH 14,5 ohms
Sec: 1930 mh 22.2 ohms
#3 LO 1166
Pri: 841 mH 14.5 ohms
Sec: 1960 H 21.9 Ohms

#4 Carnhill Re-issue
Pri: 681 mH 14.3 ohms
Sec: 1730 H 21.1 Ohms

#5 Sowter
Pri: 970 H 13.2 Ohms
Sec: 2870 H 44 Ohms

Yes they do. Individual sec sections as follows:
(I strapped them in series for the previous post)

1: 400 mH
2: 548
3: 543
4: 406
5: 733

Oh boy! I can't wait!

:green:

I have to ask a noob question here.

how do henries in these examples relate to the sound that is coming out of the transformer?

dave

The core in an regular laminated audio transformer does not work much
after about 1 kc.
After 10 kc it practically does not exist. The metal can swing that fast.
For instance if an input transformer had 40 henries of primary inductance, at 10 kc it might have 1/2 a henry, just enough to transfer the high end.

At 20 hertz and below, the magnetizing current, that is the current needed to excite the core, starts to skyrocket, almost expotentially. This increas in magnetizing current does horrible things to your sine wave. This is why most xfmr companies only spec from 20 to 20 kc. They don't want you to see what is happening to your signal below 20 hertz.

Things can really get ugly below 10 hertz, and at 4 hertz and below, you would not want to see what has happened to your signal.

The more henries you have, the less distortion you will have at 20 hertz and below.

thanks, that was a good explanation. A henry is a measure of inductance?

The more henries, the better the low end response, is there a balancing tradeoff for having too much henries?

dave

Dave has got it!

No not really but you cannot get all thing for free.
If you wound the transformer to give you lots of henries
(i.e. an audio choke) the capactiance of the windings
and the size of the parts would get you. No free lunch.
If you used some exotic core materals with more inductance
with the same # of turns the material usually cannot stand
high level audio very well as the material will saturate.
You would sacrfice high freq. response or signal handling level.

what about bigger cores instead of more turns or diferent material?

I mean... If you have the same windings in a bigger core of the same material, you have more inductance, and the winding structure is the same...

Thats right. And you might say,"Well almost all audio is above 20 hz, most speakers won't even handle 10 hz" , which is correct, but the distortion at those low freqs have an effect on the notes above them.
And I should add that the effects of magnetizing current only occur when the transformer is being driven hard. A low level signal at 2 hertz will have no problem getting thru the transformer.


Sweep tests going good, not much of a resonant peak, only a jump of about 20 percent at about 125 kc unloaded.

[quote author="CJ"]Sweep tests going good, not much of a resonant peak, only 1 volt at about 125 kc unloaded.[/quote]

Interesting... This got me thinking... Why NEVE used a RC network across the secondary of the LO1166...? I always thought it was because of a peak in the FR.

Maybe this sweep test would change with the DC running at the primary???