JLM Baby Animal

[bluezplaya]

Well that's what I have are the Fabio 2520's so I will leave it alone. :grin:

Adam
:sam:

 

[3nity]

No problem matt altough i think i'll deserve free gear with that? :green:

Nice people from Australia over here....i remember as teen watching Hartley....don't ya???

 

[James HE]

quick odd question.

What is the spacing betwen the switches on the babay animal pcb? I have an enclosure that I might try to use that has a similar layout to what one would need for the baby animal. I just want to know how close it is to being the same or if I'll need to mount switches off board. also hole diameter required.

 

[Purusha]

It's 11.75mm

 

[Jonkan]

i just got the dpdt switches that i ordered for my BA pres...and guess what..

I ordered the wrong type (24 of them)

I ordered the type with straight legs...damn!

And now i cant find any place in sweden that sells the other kind cheap. Except for one place, but the switches they have there dont have any threads , so i cant mount the pcbs to the faceplate with those.,,, I should have just gotten everything from JLM and not just the pcbs and iron.

Anyone know where i can get these kinds of switches for cheap in europe?

/J

 

[John Hardy]

John Hardy i find it to clean to my ears, good on all frequencies.
BB OPA2604 and Signetics NE5532, was hard to tell the difference but the main thing it's their gain, higher that JH 990c!

I'm not sure if you are referring to just the op-amps, or complete circuits with different input transformers that have different impedance ratios.

Regarding the op-amps themselves, the closed-loop gain of an op-amp is determined by the components around it, namely the feedback loop and the resistance from the inverting input to ground. If you experienced a difference in gain among various op-amps, it is probably due to some other factor than the op-amps themselves.

If you are referring to complete circuits that include an input transformer with a different impedance ratio used with each type of op-amp, then it is the transformer that has higher or lower gain, not the op-amp. I use a very low ratio transformer (1:2 impedance ratio) with my preamps because it is the ideal ratio for use with the 990C to achieve the lowest noise. There will be lower gain from the low-ratio transformer than one with a higher ratio, but the performance of the low-ratio transformer is better (wider bandwidth, lower distortion, more linear and extended phase response, etc.).

Please clarify how you came up with the higher gain for the OPA2604 and NE5534 vs. the 990C. Thank you.

John Hardy
The John Hardy Co.
www.johnhardyco.com

 

[3nity]

Dont get me wrong John, th JH 990 its a great DOA. And yeah you came to clarify and remember me that i might forgotten the Ratio settings....that could be a tricky way to have differencies..let me verify that....

Sorry for the incovenient this may produce..

 

[3nity]

John Hardy....i'm really sorry, at the moment of doing those listennings sessions i was in High ratio setting...i'm really sorry!
Anyway i'm getting 1 pair of JH, 1 pair of melcors and 1 pair of 2520...

This question is for JLM, i was thinking about this...is there anything i could to switch the ratios?? like a switch? or something??

 

[mattmoogus]

Hey John and 3nity,

I noticed this and meant to comment earlier but forgot. Of course the gain difference has nothing to do with the 990C as any opamp put in the same place will have the same gain.

Im assuming 3nity is running his BA with no output transformer, so when he puts in a 5532 or OPA the extra opamp stage is used as a unity inverting stage to give an electronically balanced output, which of course is 6db hotter than the unbalanced out you get when you use any DOA.

For a 'fair' comparison you need to wire your output unbalanced from the + output and the 0v point, that way DOAs and 8pin DIPs will have the same apparent gain.

John, it was nice to meet you at AES, put a face to the name etc. Thanks for stopping by here. :thumb:


M@

 

[3nity]

Couple of not so good shots of my BA...

Front...didn't came as good as i was hoping but still has some class...No engraving..maybe no time or money

The chassis came from an B* unit, with XLR's and 1/4 already drilled...it made well the job..... :grin:

Hope i did well representation of the boads made by JLM!
BTW: i'me getting at least 4 more!! :green:

 

[3nity]

Matt, im using OEP's in my BA, do you thing it's worth installing a switch for High Ratio and Low Ratio??? i was thinking about put it on the rear??

 

[craigmorris74]

I'm also need to know what Brand and part # the front switches are. I've got my 4 BA channels working, but I've somehow busted two of the switches on one channel!

 

[matta]

Craig,

I'm not sure which ones your have but Joe has switched to the brand I use called Salecom which I personally believe are of better quality than the older switches, but I may be biased :green:

The Salecom ones he is using now are T8021L Series.

I hope that helps.

Cheers

Matt

 

[JLM Audio]

BB OPA2604 and Signetics NE5532, was hard to tell the difference but the main thing it's their gain, higher that JH 990c!

The gain difference between any single 99* type and the Dual DIP IC will be 6dB in a baby animal mic pre with no output transformer due to the other half of the DIP IC opamp being used as a balanced inverting stage which adds 6dB. If you want to make your JH990c opamp baby animal pre the same gain just change Rg from 68ohm to 33ohm.

i just got the dpdt switches that i ordered for my BA pres...and guess what..

I ordered the wrong type (24 of them)

I ordered the type with straight legs...damn!

And now i cant find any place in sweden that sells the other kind cheap. Except for one place, but the switches they have there dont have any threads , so i cant mount the pcbs to the faceplate with those.,,, I should have just gotten everything from JLM and not just the pcbs and iron.

Anyone know where i can get these kinds of switches for cheap in europe?

I'm not sure which ones your have but Joe has switched to the brand I use called Salecom which I personally believe are of better quality than the older switches, but I may be biased

The Salecom ones he is using now are T8021L Series.

We always use Salecom switches unless we have not been able to get stock and all new BA kits have Gold contact ones that we have had custom ordered direct from Salecom by the 1000s. We can supply them separate for $4AUD. If you need them just send a email to my normal email address.

The chassis came from an B* unit, with XLR's and 1/4 already drilled...it made well the job.....

Hope i did well representation of the boads made by JLM!
BTW: i'me getting at least 4 more!!

Good to see B* gear being used for some thing useful :wink:

 

[Holger]

Can someone help me here? I finished my second BA (my first was perfect BTW) and did some measuerements. The result is that I am unable to get +48V at the primary green and red input transformer cables as well as on one of the four points above the transformer marked @(on my first BA I am only able to get +48V on two of the four points BTW). Any hints?
Thanks

 

[craigmorris74]

Anytime I failed to get proper voltages anywhere on my BA, it was due to sloppy soldering causing solder bridges. Go double check your work, and make sure one of your joints doesn't spill out to ground anywhere.

Also, what opamp/transformer combo are you using?

Craig

 

[Holger]

I used a magnifying glass to check all my solder points, I am still convinced that my work is not that bad, I compared each solder point to my first BA....I have the 99V/ JLM 1:4 ip/JLM 1:1:1op combo

 

[Holger]

I solved the problem, it was a bad connection between the DI and the pre. I found that by reading the schematic, something I usually try to avoid because I'm not an EE. After deconnecting the DI's 10 pin connector and fitting the jumpers, everything works as expected. My first complete DIY, now I am infected by the virus and I blame Joe a little bit for that ;-) I really like his preamps...[/i]

 

[Lowfreq]

Welcome to the addiction. :wink:

 

[Holger]

Thanks. Plugged my Fernandez in the BA, send that signal through my favourite Altec 1612A and played for an hour. Marvellous guitar signal.
My next project, after finishing an GSSL, will be a dual 1176. As mentioned earlier, I am infected now...