JLM99V

m not trying to throw fuel on the fire here, and while an audio precision is probably nice ot have around, the real ttest for me is the sound these things make come out of speakers.

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AMEN!
:thumb:

Life is too short and diy is whatever u make it...

As Dave say's it's about what comes out the mons and into ya ears that matters - specs, terminology and knowhow all have there place but if your feelin the sound that's all that counts I think...

:guinness:

sorry guys
can't just let it go
a bunch of comments like this need to be investigated ...

Took a while to get the zip files above but I'm having a look now.

a series of pictures comparing both input and output trafos and I think size is the main focus.
Also a pisture comparing laminations.

Once again, I state that the JLM output trafo is not a clone of the Neve.
The lamination size was chosen for specific resons and coloured sound was high on the objectives.
Time was spent creating a transformer different to many others.
This is a transformer that can be used in a varienty of circuits.

I think one of the trafos used as a comparison is HUGE ... it doesn't suprise me that it has better low frequency distortion curves.

As for input
it does look like Igor has a JLM input on the bench for testing which is very cool as I don't have one yet so this must be a very recent delivery.

Where did you get these and does the owner know you have them under test ?

Israel ... Tel Aviv ? :roll: I think there has only been one delivery in your direction ??
I wonder who the owner of these mic-pre parts is ?
I'm guessing you have your hands on the rest of the mic-pre kit and are also critical of them too.
I also wonder what he may have to say about your comments here. Is he looking to buy more and are you in some way just trying to change his opinion and obtain a contract of some sort ?

It could all be a language or cultural difference :roll:
but so far I can't see any thing in the pictures that is unexpected.

I was asked by some people to remove these posts
and ap test for theirs commercial reasons. OK, understood ;-)
I had no any commercial interest in this, just wanted to find some true.
And...

I think there has only been one delivery in your direction

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Yes, Kev, sometimes these things happens in Israel.

You, high culture folk.

[quote author="ijr"]I was asked by some people to remove these posts
and ap test for theirs commercial reasons. OK, understood ;-)
[/quote]
what ?
not by me and I'm not going to remove my posts ... not for anyone
I didn't delete posts as a mod at Tech Talk and I would never totally remove a post for any reason.
I would consider editing a post for obscenities or racist reasons ... and maybe for a litigation reason to protect the forum
BUT never just cos someone asked me to.
I just don't get where you are coming from.

I had no any commercial interest in this, just wanted to find some true.

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neither do I
and
so do I

Yes, Kev, sometimes these things happens in Israel.

Click to expand...

of course things happen out your way

in your part of the world is one of the biggest mastering and production houses in the world.
(CharlesT registered with this forum today ... is he someone who works there ? )

You, high culture folk.

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:shock:
Australians ... deported British Convicts
:shock:
high culture ???

.... a little over 100 years old and we have culture.

wow
I'd never noticed before

excellent :thumb:

Gday....passport please.
Morning... there you go.
Do you have a criminal record?
Er...NO...I didn't realise you still had to have one!!

Ayethengyaw. :green:

Got my 2x 99V kits into box finally (no photos yet). Is it normal that the inverted phase signal sounds so different to the normal phase (maybe it's because of the headphones I was wearing)? There can't be anything wrong (both channels sound similar)? I used the OEP input tx's and a single 99V per channel, no output txs (which might be useful to give some more gain). SM57 doesn't have much output, B*hringer XM8500 actually sounds a lot better. Condencers are just fine. So far excellent sounding pre.

[quote author="peter purpose"]Gday....passport please.
Morning... there you go.
Do you have a criminal record?
Er...NO...I didn't realise you still had to have one!!

Ayethengyaw. :green:[/quote]

Hahaha! Can hardly wait to spring that on some of my friends from Oz.

[quote author="mhelin"] Is it normal that the inverted phase signal sounds so different to the normal phase
... There can't be anything wrong (both channels sound similar)? [/quote]
:roll:
that doesn't seem right
Some units can give different results in the pos and neg when near saturation
BUT
the JLM99 would not be one I'd expect that result.

as far as the both channels ... it's possible you have done the same error in both channels
That ASSUMES there is an error ... and there may not be

An error in the power supply will effect both channels.
Which power supply ?
Do you have both pos and neg rail from power supply with both mic-pres attached and signal running ?

I guess your monitoring system could give strange results but it would also give strange results on all your gear ... ??

I think it's just because the MDR-V400 (dj style) headphones leak the sound and as I was holding the mic in my hand there must be some feedback from the monitoring system to mic at high gains. I recorded some talking and flipped phase while recording and there was basically anything different, also the wave format in sampe editor didn't show any clipping. So there's nothing wrong. But there's one thing I noticed: as you know the vocals have some "DC offset", the wave format is little bit asymmetric. I remember having seeing some mic pre, compressor or plugin (?) addressing this issue, they must use some kind of servo system to make the vocal wave format symmetric (in relation to zero). The benefit is the added headroom for vocals (does there exist similar circuit in Lab somewhere?). So does anyone remember which way the vocal wave should be offsetted? In my recording at normal phase the negative half wave seemed to have more energy. The JLM99MB/99V isn't supposed to invert the signal anywhere (except when you switch the phase switch - I have built the pre with the relays and the separate switch/led pcb).

Edit: At least this plugin has implemented the asymmetric vocal compression: http://www.voxengo.com/doc/voxformer/
The pre was the TFPro P4: http://www.tfpro.com/products/info/26.php See the before/after pics there, seems they have the vocals at same phase as me :wink:

No voice or instrument should ever be capable of producing DC. DC comes from a power supply and can show up in the audio output of a circuit if nothing's there to filter it out. If DC can even be produced by natural means then it's news to me. :? Last time I checked it was physically impossible.

Here's what I assume the problem is... if you don't have output transformers then you probably stuffed the 99V boards for DC servo instead of blocking capacitor. I believe there are little trimmers that must be adjusted until your VOM reads 0VDC at the output. Untill you do this there will be DC from the output and it will get recorded and offset your waveform display in the DAW. Otherwise I suppose you could have a VERY leaky blocking cap (unlikely) on the output OR there is a no cap, and another problem with offset somewhere further upstream.

Thanks Jens (and Kev), but it's ok. I didn't mean DC offset but actually AC offset. Yes, see the TFPro pages, it's all there. Sample some vocals with DAW and look at the waveform. My problem was a tiny acoustic feedback

[quote author="mhelin"]I think it's just because the MDR-V400 (dj style) headphones leak the sound and as I was holding the mic in my hand there must be some feedback from the monitoring system to mic at high gains. I recorded some talking and flipped phase while recording and there was basically anything different, also the wave format in sampe editor didn't show any clipping.[/quote]

Don't worry. It is a tipical user error. If you monitor in phones and you sing into the mike and change phase there will be always a change in sound because direct sound and amplified sound will summ different in your ear if the signal is in phase or phase reversed.
You can do the next test to confirm that there is no problem. Monitor in headphones but ask a different person to sing into the mike in another room and then flip the phase switch. There should be no difference or very very small (in some cases but not with this inverted opamp topology).

chrissugar

TFpro
:green:
Ted and I have had some interesting email conversations

I tend not to agree with some of his descriptions and use of tech words and specs ...
His marketing department ( a family member I think ) take this terminology and SPIN it even futher.

I'm with Chris on this ...

your wave form may be asymetrical ... some mic-pres and line drivers may sound different with a flip of phase.
The JLM is one I would expect to be close to symetrical.

I also expect most comp side chains to resond to the above signal in a similar way in either polarity.

we love Ted
honestly...
our emails were chearful and Ted was very chatty and giving
good converstion and we just aproach things differently

for those of you looking for those mini relays in the states, mouser carries them:

search on A-5W-K, fujitsu mini signal relay

regards

ju