Gapped transformer in a non-gapped application ?

[Bauman]

What happens if I use a gapped transformer (ie. a Neve output one) in a non-gapped application (like API micpre out?) . Does it work properly?

thanks.
Fabio

 

[gyraf]

Yes.

It will just have magnetic capacity to spare..

Jakob E.

 

[Bauman]

Thanks! Cool idea btw Jakkoo...

cheers!
Fabio

 

[rafafredd]

Fabio, if you are thinking about the audiolink 600/600G, it has an inductance of 0.6H on the primary, so an API opamp will drive it easily... no problemo.

The DC on primary switch idea is very interesting. You should try more current than what´s used in the neve circuit. This transformer stands up to 90mA DC on it´s windings.

 

[wilebee]

so the sam could be said for the utc a25 in place of an a24 ?

Wil

Wilebee

 

[Guest]

[quote author="Bauman"]What happens if I use a gapped transformer (ie. a Neve output one) in a non-gapped application [/quote]
Only worse low frequency response. But if it is FeSi core at output
transformer and BIG levels, you can get interesting dynamic bass boost.
Permeability of the FeSi is large by 1000 percents over initial at large signals.
xvlk

 

[CJ]

yes the A25 will handle 8 ma dc. notice a slight reduction in low end, 40 instead of 20 hertz, due to the drop in inductance due to the gap. same core, less windings.
but it is 15k input, too hogh for the API.

Neve output, try it and see. whats the output impedance of that 3055? should be pretty low.
don't need a cap on the end of the API if you use the gapped transformer.
cj

 

[Tekay]

I did a frequency sweep comparison between LO1166 and LO2567, both driven with a BA438 / BA440 based pre (1081 pre section) and this is how the sweep turned out! http://www.vintagedesign.halmstad.net/docs/1166_2567.pdf

Blue curve is the LO1166, couldn't measure any distortion diffrencies with my distortion poor meter. (old Ferrograph) The built in oscillator has higher distortion than the tested unit!

 

[Bauman]

I end up with a spare Neve out trafo, that´s why the question came up. I didn´t imagine it would be a plot done! Pretty crazy in here...

TK, I like that bump in the botttom, lets hear it now. I´ll let ya know.

thanks all!!!
:sam: :sam: :guinness:
Fabio

 

[CJ]

Great work TK!
Did you use the standard termination for thr x-former tests?

 

[Tekay]

I did the measurement with a 604 ohm over the sec winding as termination!
The HF peak is from the input transformer, I think?
Can't remember if I had the prim windings in serie or parallell on the LO1166, the LO2567 prim is in parallell and I think I did the same with the LO1166 :?

 

[Tekay]

Hope to make more nice curves when I've change my soundcard to a better with balanced inputs and 192kHz sample rate, then I can sweep up to 96kHz :razz:
M-Audio has a new card out on the market that probably will work fine with Audio Tester! "Audiophile 192" today I use the 2496. Cheap but good to only do sweeps with.

Cheers all! :thumb:

 

[Flatpicker]

Good info as I was wondering about that myself.

I tried to ask the same thing here:
http://www.groupdiy.com/index.php?topic=1748&highlight=

 

[CJ]

Don't forget what PRR told us a while back, you need to put some , say, 30 ohm resistors in each leg of the signal generator feeds in order not to get weird LF peaks due to you generator combining with the transformer and doing resonant types of things.

 

[Tekay]

CJ! Do you mean that I shall put in serial resistor between the driver amp and the 1166 if I use it with a standard class AB driver?

 

[Swedish Chef]

TK!
Beware of the MAudio claims. I have an interface, Quattro, and it says 24bit 96khz, but is brickwalled at 22kHz!
Beware :? :sad:

chef

 

[Tekay]

My Audiophile 2496 workes fine in 96kHz mode, but I coudn't get it to work together with the Audio Tester without the asio option!

 

[CJ]

TK, i use the serial resistors with the sig gen when doing lab work, but not in the actual finished product.
cj