Electro Harmonix 12AY7 Tube Mic Preamp

[OldMan]

Hello all

Please can anyboody make a picture (inside view) from this peace of gear?
I just want to check how many trannies are in this box!

Thaks

Greetings from switzerland
OM

[retractablezing]

the 12ay7 is transformerless.

if you're asking about how many trannies, i doubt you'll make something out of a guts picture...

if you're having doubts about purchasing it, rest assured that it's a quality pre. i'dd try to find an earlier run, the later ones have poorer quality control.

[TurboJets]

Originally Posted by retractablezing

the 12ay7 is transformerless.

if you're asking about how many trannies, i doubt you'll make something out of a guts picture...

if you're having doubts about purchasing it, rest assured that it's a quality pre. i'dd try to find an earlier run, the later ones have poorer quality control.

+1 on this, however I'm not so sure the QC is any different now than it was in the very beginning - EH engineer's argue QC is great.

No room for tranny's in that box, it's jammed full. You'd have to rackmount everything and make the mod yourself.

Excellent sound, excellent pre that has focus, dimension, tight lows, smooth mids, and silky highs. It's very flattering for vocals, superb on ac guitars, and perfect for toms.

[OldMan]

No Pics? Please

And no semiconductors?

[TurboJets]

I doubt you'll get any pics because when you remove the casing it's only the backside of the pc boards that's revealed. To view the component side of the pc board you'd have to disassemble control knobs and switches. Only someone who has actually rackmounted the guts will have those kind of pics.

Yes, there are semiconductors; there's at least 1 IC on the board.

[OldMan]

Originally Posted by TurboJets

I doubt you'll get any pics because when you remove the casing it's only the backside of the pc boards that's revealed. To view the component side of the pc board you'd have to disassemble control knobs and switches. Only someone who has actually rackmounted the guts will have those kind of pics.

Oh yes I forget that!

[retractablezing]

Originally Posted by TurboJets

I doubt you'll get any pics because when you remove the casing it's only the backside of the pc boards that's revealed. To view the component side of the pc board you'd have to disassemble control knobs and switches. Only someone who has actually rackmounted the guts will have those kind of pics.

Yes, there are semiconductors; there's at least 1 IC on the board.

that's not true actually, i've taken it apart without having to disassemble controls, etc. it's still a pain in the ass and i don't have those pictures anymore.

the only IC in it is for the 1/4" output and that's the one meant only for monitoring, no one should use that one anyway.

[retractablezing]

Originally Posted by TurboJets

+1 on this, however I'm not so sure the QC is any different now than it was in the very beginning - EH engineer's argue QC is great.

i've had 2. in the beggining no one was complaining about hum issues. my initial one doesn't hum (even with old as hell valves in there, and really odd ones too) and it's the one ive kept. my second (much later serial nr) hummed like there was no tomorrow.

[TurboJets]

Originally Posted by retractablezing

that's not true actually, i've taken it apart without having to disassemble controls, etc. it's still a pain in the ass and i don't have those pictures anymore.

the only IC in it is for the 1/4" output and that's the one meant only for monitoring, no one should use that one anyway.

It's totally true, read my post more carefully. When you remove the black (bottom) casing you openly expose the underside of the pc boards. The only view of the actual components is a side-view which is no good for closeup pictures.

Also, the 1/4" monitoring output works just fine as an additional output to track with. Yes, it's buffered, but sounds great; I use it sometimes with excellent results.

The first 2 units I bought had problems and I bought them almost immediately after the initial offering. Go figure, right?

[retractablezing]

Originally Posted by TurboJets

It's totally true, read my post more carefully. When you remove the black (bottom) casing you openly expose the underside of the pc boards. The only view of the actual components is a side-view which is no good for closeup pictures.

Also, the 1/4" monitoring output works just fine as an additional output to track with. Yes, it's buffered, but sounds great; I use it sometimes with excellent results.

The first 2 units I bought had problems and I bought them almost immediately after the initial offering. Go figure, right?

you can remove the upper side, without having to do anything to the controls, thus exposing all components, i've done this. the only thing that is left hanging from the pc board to the upper side is one of those ribbon connectors.

is this what you're saying?

it is buffered though, and despite sounding fine, it's not the one most ppl would want to use, i suppose.

ok i stand corrected on the QC issues. i suppose i was lucky.

[TurboJets]

Originally Posted by retractablezing

you can remove the upper side, without having to do anything to the controls, thus exposing all components, i've done this. the only thing that is left hanging from the pc board to the upper side is one of those ribbon connectors.

is this what you're saying?

Yes. That was me being a nitpicking PIA. Sorry.

[retractablezing]

no worries. it ain't easy though, and it's tricky to put everything back exactly the way it was.

[OldMan]

Hmmm it looks like you have to practice the dissasemble/reassemble thing a little bit

[OldMan]

Finally found:

[ghetto3jon]

anyone know where that pic of the 12AY7 guts came from? i was thinking of getting one of these to mod/re-tube, but it's tough to find pics or schematics...that pic is the only one i've ever seen...

[MATTI]

Search here Tape Op Message Board :: Index

Matti

[OldMan]

I found them somewhere sorry forgotten where sorry but this was the best one.

I made better ones by myself I will send it to you tomorow (i hope I don't forgett this also ;-)

But the important question is who has a schematic!

Greetings from switzerland.

OldMan / Juerg

Originally Posted by ghetto3jon

anyone know where that pic of the 12AY7 guts came from? i was thinking of getting one of these to mod/re-tube, but it's tough to find pics or schematics...that pic is the only one i've ever seen...

[MATTI]

Yes I remembered those old from Tape Op aswell -not showing it as it is but
his racking project.
I quess you could make a really good pre from this by adding some decent transformers as speculated at Tape Op

Matti

[OldMan]

Yes but whitch one is the right Output Trannie for this Preamp?
Tomorrow I try a 1:4 (4:1) 10k to 200 Ohm

Neutrik - Audio - Übertrager - NTE4

Originally Posted by MATTI

Yes I remembered those old from Tape Op aswell -not showing it as it is but
his racking project.
I quess you could make a really good pre from this by adding some decent transformers as speculated at Tape Op

Matti

[MATTI]

Tell me your impressions after that, I never went to this afterall

Matti

[OldMan]

Looks good ;-)

EHX 12AY7 Mic Preamp

but of corse I should make some saturation tests.


Just to compare Siemens V276:
RightMark Audio Analyzer test: V276

and EH 12ay7:
RightMark Audio Analyzer test: EHX 12AY7

Originally Posted by MATTI

Tell me your impressions after that, I never went to this afterall

Matti

[ghetto3jon]

i don't know about you guys, but the longer i look at this thing, the more i think there is nothing really to mod. i'm no expert, but the cap, tubes, and opamps are all fine...and it's not a starved plate design to begin with. sad to say because i love to tinker, but maybe it's as good as it's going to get (which seem to be pretty good!)

[Tomer1]

You could try a 1:1 ratio transformer on the output just to give it some color.

[MATTI]

I claim it would be ( the curve ) sraight down to some 20 hz?

Matti

[OldMan]

Well but it looks better then before (With the 1:1 Transformer)

Before:
RightMark Audio Analyzer test: comparison

And I don't think that its getting better with a 1:10 Transformer
cause now the curve is nearly the same like the one that is produced
by the Jack output (but of corse without the humm ;-)

But the "Bass cut" is a little overdone.

Don't forget it's a Vintage like Unit.

Originally Posted by MATTI

I claim it would be ( the curve ) sraight down to some 20 hz?

Matti

[Tomer1]

Well Freq graph tells you almost nothing in terms of sound.
You cant repreasent\describe "warmth" in scientific terms, Even showing 2nd and 3rd harmonics and distortion wont tell you a damn thing about the nature of the sound.