Hi guys,
That's my first post with ya'll DIYers, so first of all cheers for the good work!
I just got a hold on a pair of preamps from the sixties: EAG 's EB031 and I would like to rack them.
There's plenty of information about racking preamps on this forum, but my knowledge is often too short on the subject to really get a good understanding of the matter.
I have the schematics of the preamp, but the quality is not very good. I should have a better version of the schematics thanks to Ungifted.
EDIT: http://diyfactory.ru/forum/index.php?act=Downloads&do=download&id=169
I will now quote his description of the preamps, which he shortly introduced in another thread:
"V72-style preamp from East Europe - It uses common EF86 in the first stage plus ECC85 (...). Output signal is taken from the cathode of ECC85."
Ungifted found pictures of the unit and the schematics which are a little blurred, but usable. You can find them on the link he posted earlier: http://cruisher.digitaltrip.hu/beag/EB031/
The only difference is that I have the fader that comes sitting on top of the unit. Each fader connects to the unit thanks to the "DC2" which you can see on the schematics.
Also, I found on an eBay auction (which has now ended) that the input transformer's ratio was 1:22.
So basically my work seems pretty simple: wiring the input & output, and adding a power supply (and adding an output transformer?). I will also add the Go Between Kit from JLM Audio Shop to have phase shift, pad and phantom.
But I'm a newby at this, so I have a few questions.
My questions are the following:
-Do I need an output transformer? If I do, what should be its specifications?
-What kind of power supply should I use, and what voltages should I use? I'm looking at JLM Audio Shop but it's kinda hard for me to understand the important specifications to look after. Is there a reference which is used quite often and that would suit this project?
-And now the big question is about the wiring of the unit:
*where do I find the input? (pins 6, 16 & 15 of DC1?)
*where do I find the output? (pins 5 & 14 of DC1?) (what about sending those 2 to an output transformer and then => XLR Out?)
*how am I supposed to wire the several voltages of the power supply to the unit? (+6.3V on pin 10 & -6.3V on pin 20 of DC1?)
*Are there bridges I need to make between several pins of DC1? (for example, for the fader to be effective)
I might not know a lot but I learn quite fast, so any help is appreciated!
Thanks a lot in advance,
Regards
Haybee
That's my first post with ya'll DIYers, so first of all cheers for the good work!
I just got a hold on a pair of preamps from the sixties: EAG 's EB031 and I would like to rack them.
There's plenty of information about racking preamps on this forum, but my knowledge is often too short on the subject to really get a good understanding of the matter.
I have the schematics of the preamp, but the quality is not very good. I should have a better version of the schematics thanks to Ungifted.
EDIT: http://diyfactory.ru/forum/index.php?act=Downloads&do=download&id=169
I will now quote his description of the preamps, which he shortly introduced in another thread:
"V72-style preamp from East Europe - It uses common EF86 in the first stage plus ECC85 (...). Output signal is taken from the cathode of ECC85."
Ungifted found pictures of the unit and the schematics which are a little blurred, but usable. You can find them on the link he posted earlier: http://cruisher.digitaltrip.hu/beag/EB031/
The only difference is that I have the fader that comes sitting on top of the unit. Each fader connects to the unit thanks to the "DC2" which you can see on the schematics.
Also, I found on an eBay auction (which has now ended) that the input transformer's ratio was 1:22.
So basically my work seems pretty simple: wiring the input & output, and adding a power supply (and adding an output transformer?). I will also add the Go Between Kit from JLM Audio Shop to have phase shift, pad and phantom.
But I'm a newby at this, so I have a few questions.
My questions are the following:
-Do I need an output transformer? If I do, what should be its specifications?
-What kind of power supply should I use, and what voltages should I use? I'm looking at JLM Audio Shop but it's kinda hard for me to understand the important specifications to look after. Is there a reference which is used quite often and that would suit this project?
-And now the big question is about the wiring of the unit:
*where do I find the input? (pins 6, 16 & 15 of DC1?)
*where do I find the output? (pins 5 & 14 of DC1?) (what about sending those 2 to an output transformer and then => XLR Out?)
*how am I supposed to wire the several voltages of the power supply to the unit? (+6.3V on pin 10 & -6.3V on pin 20 of DC1?)
*Are there bridges I need to make between several pins of DC1? (for example, for the fader to be effective)
I might not know a lot but I learn quite fast, so any help is appreciated!
Thanks a lot in advance,
Regards
Haybee
