12AY7 Mic Pre question...

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e-dog

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i'm new posting here, very little recording experience..

i bought an Electro-Harmonix 12AY7 Mic Pre and have
been testing it out some, i really like the sound, but it
seems to be lacking high frequencies (more obvious with
some mics than others) compared to using using my
cheap ART Tube MP...

i was really excited about getting a "class a" "all-tube"
preamp, and am wondering if abyone else has the same
unit, if it's a common problem, or maybe just inherent in
all tube amplification?

is there a possible modification to fix this (little high end)?

thanks for any info or advice.
 
Hmmm... haven't had that issue with mine. You probably already know that the XLR out is a much higher quality signal than the 1/4" out (the 1/4" out really only good for monitoring).

Tim
 
The cheap transformers and tubes in these guys will give varying results..some units "brighter" than others...maybe you got a bum unit? QC on these lower end pieces is pretty loose...

Ray
 
FWIW, I have two that sound identical. Been lots of discussion about the EH pre here at times but I don't remember comments about quality control problems - just noise issues when going to an unbalanced soundcard input. And of course the lower quality sound of the pre's 1/4" TRS jack.

Tim
 
Timothy Lawler said:
And of course the lower quality sound of the pre's 1/4" TRS jack.

Tim
Click to expand...


A cord that is TRS will be exactly the same as a XLR if you use the same quality cable. Its just a connection from points A, B, and C. It doesn't matter how they are lined up. If that was the case, then a lot of efx sends and returns on many professional mixing boards would be degrating the sound quality and thsoe companies would have never used them.
 
Outlaws said:
A cord that is TRS will be exactly the same as a XLR if you use the same quality cable. Its just a connection from points A, B, and C. It doesn't matter how they are lined up. If that was the case, then a lot of efx sends and returns on many professional mixing boards would be degrating the sound quality and thsoe companies would have never used them.
Click to expand...
Of course it's not the cable and plug type that's causing the difference in sound quality. That would have nothing to do with it.

It's the volume pot on the TRS out, and perhaps some other internal circuitry that causes the difference. If you have one of the pre's and listen to the difference between the two output jacks you'll see what I'm talking about.

Tim
 
e-dog said:
i'm new posting here, very little recording experience..

i bought an Electro-Harmonix 12AY7 Mic Pre and have
been testing it out some, i really like the sound, but it
seems to be lacking high frequencies (more obvious with
some mics than others) compared to using using my
cheap ART Tube MP...

i was really excited about getting a "class a" "all-tube"
preamp, and am wondering if abyone else has the same
unit, if it's a common problem, or maybe just inherent in
all tube amplification?

is there a possible modification to fix this (little high end)?

thanks for any info or advice.
Click to expand...

If you're going into a mixer after the preamp, make sure that your high freq trim isn't turned down.

I know -seems like a stupid response, but I do bonehead stuff like that all the time.

JD
 
Timothy Lawler said:
Of course it's not the cable and plug type that's causing the difference in sound quality. That would have nothing to do with it.

It's the volume pot on the TRS out, and perhaps some other internal circuitry that causes the difference. If you have one of the pre's and listen to the difference between the two output jacks you'll see what I'm talking about.

Tim
Click to expand...


Gotcha. ;)

I just looked at that thing. Looks like the output level knob it almost like a limiter or just a simple volume so you can get the tube compression/clipping/overdrive while not blasting whatever is on the recieving end. Either way, a limiter or volume could cause high end loss.
 
thanks for responses

No, the issue wasn't with the 1/4" jack...
I found the sound out of that pretty unusable early on.

I've tried switching tubes (same value) and that seems
to help some, the 12au7 in particular needed upgrading,
the 12ay7 (tube) itself is fairly bright, so i left that in...

i'm thinking it could be a mic or soundcard issue instead,
the soundcard not being balanced and requiring a tran
in the signal path (which is NOT causing the loss of highs,
i a/b-ed that already, it's for hum)...

also on the quality control point, this is actually my second
unit, the first had HORRIBLE clipping with every signal and
then after about six hours of light use (total) shorted out
and could not pass a signal, the unit was replaced by the
dealer and works great now, much less noisy and NO clipping.

so, on occassion, there is a "bum unit" but mine seems okay.

except for a slight case of missing highs.
still sounds good though, fat and dynamic.

thanks for all the responses, everyone.
 
Being on the subject, mind if I pose a question?

My 12ay7 pre came with two 12ay7 in it, and I was wondering
if any of you could tell me which position has the 12au7 in it,
say when looking top down, as I'd like to swap mine to the
default configuration.

Best regards
Kim
 
Supergroupie,

The 12AU7 tube goes in the left position, looking straight at the unit so you can read the print. This is the driver tube. The right tube is the pre tube.

Hope this helps,

Lucio
 
Wait, what?!?!

the 12au7 is a driver?

does the signal go through it, is driver the same
as "amp section"?

i switched out the stock EH 12au7 in mine with
an NOS and there was a HUGE chage in the sound..
much clearer, better definition, much cleaner bass
(the stock tube had a weird pumping/warbling/
overemphasis), and cleaner upper mids/highs.

was i imagining things?
would switching out the EH12ay7 make a bigger
difference?

anybody?

although, i'd have to say i swapped an NOS rca
with the EH in a tube mic, and liked the EH better,
so probably not. but i'm out of spare tubes for
random swapping anyway...

.
 
cool, thanks LDT2...

great link/thread. i was a bit worried to use any
tubes with different ratings, but i think i'll have to
give that a try.


.
 
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