[oragall]

i have a edcor pc 1/4W  series (600 to 15K) , the relation of this trafo is 1:5 , work well,  ot not with this trafo.?

[Bo Hansen]

oragall,

Not the best impedance match, but try it, you newer know, maybe it will work fairly good.

--Bo

[Soeren_DK]

NEWS FLASH
The boards is now available in gustavs shop
http://www.groupdiy.com/index.php?topic=10776.0

Cheers
Soren

[[silent:arts]]

I think I need to place an order tomorrow.
to Gustav and Haufe 

[oragall]

tnx bo, maybe y test whit the trafo. Need only time, but now i finish other project.

[sonolink]

I'd like to have a go at self-etching this board. Any chance the final PCB version could be posted, please?
Cheers

[juanjovincenzo]

Hi Guys!!

I would like self-etch my own PCBs too. 

If it is possible, please, post the Final copper side layout and the silk side.

Thanks for this thread and best regards
mucha suerte y chao

Juanjo..

[briomusic]

Between Christmas/New Year I will try to do a transformer test/evaluation and compare Lundahl, Haufe and OEP in the DI-Box electronics.

But Just now I wait for a sample of OEP A262A3E from UK, so I will start when I receive that.

--Bo

Hi Bo,
did you ever get round to comparing the sound of these transformers in your circuit?
Would be very interested in hearing (or hearing about) results as these transformers are quite different in price etc.
Thanks,
briomusic

[pacemaker]

yes i agree,
seems that a lot of people like the OEP in this build
Cinemag too,
But your impression with Lunhdal and Jensen would be interesting
Also with Edcor, Altran ....

[sonolink]

I'd like to have a go at self-etching this board. Any chance the final PCB version could be posted, please?
Cheers

I guess that's a no no then, right?

[Soeren_DK]

I'd like to have a go at self-etching this board. Any chance the final PCB version could be posted, please?
Cheers

I guess that's a no no then, right?

Sorry guys. I didn't got so much time but I have done it now. Its in the first post..

Best regards
Soren

[sonolink]

Thanks Soren. Ur my hero 

[juanjovincenzo]

Hi!!
Thanks again Soren!!!!
"ESA ES!!!!"
BEST REGARDS
Y SUERTE

[Bo Hansen]

briomusic,

Yes, I have done some tests and compare Lundahl LL1538, Haufe ST8456 and Walters OEP A262A3E, in my DI-box circuit.

Lundahl and Haufe have near same behavior from 100 Hz and up, but Haufe are a bit better in low end small signal distortion, and Lundahl have lower distortion in low end near saturation point.

Both have a very good square wave response, and have 14 dB loss with 1 kohm total load.

OEP have approx. 10 times higher distortion from 100 Hz and down, and have also higher distortion in the high end, but have ok square wave response, slightly rounded, with out ringing or overshoot.
Because the 6,45:1 ratio, it have 16 dB loss.

All three sounds nice in my DI-box, but Lundahl LL1538 are still the best with a steady and clean low bottom and a fast and clear high end.

--Bo

[briomusic]

bo

I am sure I am speaking for many forum members in thanking you for this run down!
can't wait to build your DI now!

briomusic

[neodyms]

Hi Bo
your impression with Haufe, OEP and Lunhdal
are very interesting,
did you tested the DI with Jensen, Cinemag or Edcor
as pacemaker asked ?

[Bo Hansen]

neoyms,

Of course mike transformers as Jensen JT-13K7A and Cinemag CMMI-5C are great transformers, (maybe a bit low impedance on secundary) I have not test them in this DI-circuit, but I´m sure they will work very nice.

Cinemag have some other types as CMO-5/200, CM-2461NiCo, CM-24110 and CMMI-7C, and can maybe also fit very well in this circuit.

About Edcor,
Yes, I have test MX-5, 1:5 mike transformer.
Sorry to say, not so good, maybe it can be usable in other applications, but not for a DI-box like mine.

There are other usable brands and types that you can try:
Sowter 3195, 3678, 4935, 8230
Steven & Billington 829
Amplimo TM2P

And of course the old famous Neve mike transformer
10468 / VT22670 / T1454, (configurated 4,8K to 300 ohm)
to day made by Carnhill, type VTB9045, or Sowter 9145.

--Bo

[pacemaker]

What about the Cinemag  CM-DBX
does anybody has tested it in this circuit ?
i suppose we can use a lot of transformer brands
in order to "color" the sound
or neutrality transparency
Seems like Rotation says the OEP is a bit raw and has a nice color
I suppose Lundahl are kind of "HI-FI" and appreciated by Bo,
Francois

[spacecho]

hey Guys,

i have a lundahl ll1530 - could this work ok in this circuit?
it is a 1+1: 3,5+3,5 mic transformer which can be wired 1:7

i'm guessing that apart from a steeper level drop it should perform ok?

[llanafreak44]

So which Tranny are you Americans using? All the recommended ones are European companies.

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