JLM Baby Animal

[bluemuze]

I have the BA4 'everything' kit. The DI for the preamp all the way on the left won't fit because there's a threaded fitting in the way. I do I get it in the case?

Thanks,
Bob Miller

 

[Osse]

Hello everybody

I'm about to order 2x kits from JLM, but i'm having a difficulty choosing which configurations.

My goal is to have a 2 channel good quality preamp with the capability of amplifying ribbons in calm voices, together with variable impedance from 150 -6k ohm.

The problem is that I don't like the BAD kit with 2x jlm99v and jlm14 imput transformer soudwise.

So my question is:

Is there any possibilities of a high gain variable impedance without that low-end muddyness(to my ears)? I also think that combo is a little to sharp in the high freqs(5k and beyoynd).

I really like the sound of the OEP input + OPA opamp, but I don't think it will be enought gain?

The jlm 1.1.1 is a possibility too.

let it cost what it needs, any suggestions?

Thanks so much guys!

 

[skipwave]

The table on the JLM website quotes 72dB total gain for the OEP in high ratio config with the opa2604.

Alternatively, do the OEP input trafo and Hybrid Opamp. The heart of the Hybrid is the opa2604. The added output stage can drive a step up transformer for more gain when needed, and gives you the option of biasing in Class A or A/B. I've used them to drive Edcor WSM150:600 transformers with good results, and if you are careful about the input impedance of the following device (not loading too heavily) you can use higher ratio output transformers. I've used 1:3.5 turns ratio output transformers into hi-Z ADC inputs with good results.

 

[Osse]

but from what i've heard you should use low ratio parts to get 150ohm minimum, does it work to have the OEP in with high ratio and still get 150 ohm minimum load?

I'm also thinking about using the Lundahl, what's u're suggestion?

Thanks so much!

 

[Purusha]

[quote author="Purusha"]I HAVE A PROBLEM I CAN'T SOLVE ON MY OWN :?

One of my BAs with 1:4 + 99V + 1:1:1 doesn't work anymore.
There is almost no sound coming through, just a lot of noise.
I noticed the noise increases when I turn my variable impedance
knob CW. Otherwise the V seem to be correct and Opamp works OK.

Any suggestions?[/quote]

BUMP :sad:

 

[TomiS]

Hi y'all

First post here though I've been lurking around for well over a year.

Just finished my 2 JLM 1:4, 99V animals and love'em :razz:
I've only tried them talking to different mics and I've never heard my 57 sound so good!!!

I was so impressed with the sound that I sold my TLaudio tube pre and order 6 more BA's with different configurations.
I've got 2 lundahl trafos(1538 and 1528) that I plan on using with the hybrid opamps.

So hopefully by the end of april I'll have 8ch of baby animals.

My configuration is going to be:
4 x JLM 1:4, 99V
2 x JLM 1:4, hybrid
2 x Lundahl, hybrid

I'll do a comparison between them and a yamaha 01v96 since it's pretty popular mixer. I'll post the samples asap.

Thanks for an awesome pre and all you great people helping noobs like me.

Tomi

 

[Lowfreq]

[quote author="Osse"]I'm also thinking about using the Lundahl, what's u're suggestion?[/quote]I've got the lundahl LL1538 on a pair of dual 99v pres(not the BA's I know) and they sound great.

Um, very wide bandwidth/freq range??? Dunno ifs that the correct term........
Goes from real low to real high sounds very even to me.

It's my favourite pre for drum overheads

 

[Osse]

I wonder, what would the gain of those configs be?

Lundahl LL1578(1:10) + Hybrid + 1:1:1 out trafo(1:2)
Lundahl LL1578(1:10) + OPA2604 + 1:1:1 out trafo(1:2)
OEP262A3C(1:12,9) + Hybrid + 1:1:1 trafo out(1:2)
OEP262A3C(1:12,9) + OPA2604 + 1:1:1 trafo out(1:2)

And would I be able to get them to variable impedance 150 ohm minimum?

 

[JLM Audio]

Hi Joe,

How close to the Forsell opto sidechain is your comp? Looks like you went with a fullwave rectifier, and only two opamp stages (one 2604). One inverting and one non, each driving a fullwave bridge into the LEDs?

It's as though you read my mind; I was just figuring out how to integrate the Forsell opto with a BabyAnimal mic pre. I'm making a small box for traveling with an mbox mini. I had settled on using the LDR as the shunt R in a U-pad on the output.

All MAC info is here http://jlmaudio.com/user/viewtopic.php?t=63&postdays=0&postorder=asc&start=0

i haven't put the api style cinemag OTs in yet but there shouldn't be any mods for putting them in right?

The Cinemag output transformer should be connected up just like the JLM111DC. Remember a OPA2604 cannot drive a 150ohm load so if using a transformer use 1:1. With the Hybrid 1:2 and 1:3 ratios are fine.

HAVE A PROBLEM I CAN'T SOLVE ON MY OWN

One of my BAs with 1:4 + 99V + 1:1:1 doesn't work anymore.
There is almost no sound coming through, just a lot of noise.
I noticed the noise increases when I turn my variable impedance
knob CW. Otherwise the V seem to be correct and Opamp works OK.

Any suggestions?

If the noise goes up when the impedance and/or the gain control are turned up all the electronics is working fine. And the fact you can hear a slight bit of signal it sounds like you have one open leg of the balanced input signal. First thing with a ohmmeter check that you can see the JLM14 input which should be about 20ohms with the 48v off, pad off measured between the input XLR pins 2 & 3. IF not check the wiring from the input XLR to the +/- in on the BA PCB. The next set of contacts in the balanced line are the IDC10 socket. So if there is a DI plugged in remove it and place the 2 jumpers in the IDC10 header. IF this fixes the mic pre the switch in the DI socket is open circuit. The signal then goes to the pad switch and then the phase switch. You should be able to measure the JLM14 input of 20ohms on the top to legs of the phase switch. If you cannot measure the 20ohm here go straight to the red and green wires on the JLM14 and see if you see 20ohm between them.

I really like the sound of the OEP input + OPA opamp, but I don't think it will be enough gain?

With the OPA opamp or Hybrid RG can be as small as 22ohm which will give you the maximum gain possible. Use OEP on low ratio (1:6.45) will give 18dB + 53dB from gain stage plus OPA has another 6dB from the second inverting stage = 18 + 53 + 6 = 77dB. If using Hybrid you will get 71dB or 77dB if you use a JLM111DC output transformer wired 1:2.

but from what i've heard you should use low ratio parts to get 150ohm minimum, does it work to have the OEP in with high ratio and still get 150 ohm minimum load?

OEP262A3C is always best in low ratio (1:6.45) with 27k secondary load this give 600ohm input impedance. If you do go to high ratio the input will be 150ohm.

I'm also thinking about using the Lundahl, what's u're suggestion?

The LL1538 is so clean it is almost like not having a transformer. But the LL1578 starts to get some nice warmth which is why you want a transformer in the first place (Well at least for rock music :grin: )

[Lundahl LL1578(1:10) + Hybrid + 1:1:1 out trafo(1:2)
Lundahl LL1578(1:10) + OPA2604 + 1:1:1 out trafo(1:2)
OEP262A3C(1:12,9) + Hybrid + 1:1:1 trafo out(1:2)
OEP262A3C(1:12,9) + OPA2604 + 1:1:1 trafo out(1:2)

Lundahl LL1578(1:10) (21dB) + Hybrid (43dB with RG = 68R) + 1:1:1 out trafo(1:2) (6dB) = 70dB RL = 15k for 150ohm RL = 60k for 600ohm input impedance.

Better option is
Lundahl LL1578(1:5) (15dB) + Hybrid (53dB with RG = 22R) + 1:1:1 out trafo(1:2) (6dB) = 74dB RL = 3.9k for 150ohm RL = 15k for 600ohm input impedance. Variable RL = 3.9k in series with 50k log pot. Range 150ohm to 2.1k

Lundahl LL1578(1:10) (21dB) + OPA2604 (49dB with RG = 68R) + 1:1:1 out trafo(1:2) (cannot use 1:2 output transformer on OPA as it can only drive a 600ohm load) = 70dB RL = 15k for 150ohm RL = 60k for 600ohm input impedance.

Better option is
Lundahl LL1578(1:5) (15dB) + OPA2604 (59dB with RG = 22R) = 74dB RL = 3.9k for 150ohm RL = 15k for 600ohm input impedance. Variable RL = 3.9k in series with 50k log pot. Range 150ohm to 2.1k

OEP version are the same as above lundahl version plus about 3dB of extra gain and also best used on low ratio 1:6.45 and RG lowered to 22R when using a Hybrid or OPA2604. RL = 6.2k for 150ohm RL = 27k for 600ohm. Variable RL = 6.2k in series with 100k log pot. Range 150ohm to 2.4k

 

[Osse]

Thanks for the great help Joe, this really helped a lot in my choice.

How would you describe the difference in character between the OPA and Hybrid op-amps?

And even the LL1578 and OEP trafo? which one would you recommend? as I said I really liked what I heard from the OPA + OEP, but I want a really good pre, and from what i've heard the OEP should not be the best alternative.

Thanks once again!

 

[skipwave]

[quote author="JLM Audio"]All MAC info is here http://jlmaudio.com/user/viewtopic.php?t=63&postdays=0&postorder=asc&start=0
[/quote]

Thanks Joe. I posted in that thread on your forum, and you got me sorted. :thumb:

 

[Godders]

[quote author="Osse"]Thanks for the great help Joe, this really helped a lot in my choice.

How would you describe the difference in character between the OPA and Hybrid op-amps?

And even the LL1578 and OEP trafo? which one would you recommend? as I said I really liked what I heard from the OPA + OEP, but I want a really good pre, and from what i've heard the OEP should not be the best alternative.

Thanks once again![/quote]Not sure where you heard that, I have OEP in two channels of BA with JLM 99v opamp and Lundahl 1578XL in the other two with JLM hybrid opamp.

They're different but one's not really better than the other. I find the lundahl/hybrids a little cleaner, good for acoustic instruments/overheads. The OEP/99V have a little more colour. It's nice to have the choice but I'd quite happily live with either pre on any source.

I also have OEP transformers (in and out ) in my G9 (as do many others). Don't let the price fool you, they're nice quality transformers.

Cheers

Nick

 

[Osse]

[quote author="Godders"][quote author="Osse"]Thanks for the great help Joe, this really helped a lot in my choice.

How would you describe the difference in character between the OPA and Hybrid op-amps?

And even the LL1578 and OEP trafo? which one would you recommend? as I said I really liked what I heard from the OPA + OEP, but I want a really good pre, and from what i've heard the OEP should not be the best alternative.

Thanks once again![/quote]Not sure where you heard that, I have OEP in two channels of BA with JLM 99v opamp and Lundahl 1578XL in the other two with JLM hybrid opamp.

They're different but one's not really better than the other. I find the lundahl/hybrids a little cleaner, good for acoustic instruments/overheads. The OEP/99V have a little more colour. It's nice to have the choice but I'd quite happily live with either pre on any source.

I also have OEP transformers (in and out ) in my G9 (as do many others). Don't let the price fool you, they're nice quality transformers.

Cheers

Nick[/quote]

Very interesting, as I've thought about just that combination(LL1578 and Hybrid). Would you recommend it? I want a very high quality pure clean(maybe a little warmth) in-your-face sound for vocal and DI recordings(bass, guitar), and hopefully a good pre for Room mics.

How much gain does it give?

 

[Godders]

Well yeah, it's high quality and clean sounding.

In your face? I'm not really sure what you mean by that, I've never really got an "in your face" sound from a mic pre, these terms mean different things to different people I guess. Like I said I tend to veer towards it for acoustic instruments and overheads, for vocals I'd more often rather use the OEP/99V combo to be honest (although my go to vocal pre is the G9).

If you want clean and high quality I think you'd be very happy with the 1578/hybrid combination.

With ration set at 1:10 the gain is 64db, output tranny will give you another 6db I believe, I'm sure Joe will put me right if I'm wrong there.

Cheers

Nick

 

[Osse]

Interesting, Thanks so much for the info!

I wonder, how is the sound difference betwen the OPA and Hybrid OP amp?

 

[TomiS]

I've got 6 more channels of BA coming and I'd like your opinion on something.

Which will give me more tonal versitality, an A/AB swith or an impedance pot on an LL1538/hybrid and JLM1:4/hybrid combos?

I was thinking of putting an A/AB swith to the other 4 channels with hybrid opamps instead of impedance pot. Do you think that's the way to go?

Thanks

 

[JLM Audio]

Which will give me more tonal versatility, an A/AB switch or an impedance pot on an LL1538/hybrid and JLM1:4/hybrid combos?

I was thinking of putting an A/AB versatility to the other 4 channels with hybrid opamps instead of impedance pot. Do you think that's the way to go?

Impedance pot with the HYBRID opamp left in Class A.

Variable impedance is like having a Pultec high boost/cut control for free and is the way to go.

 

[TomiS]

Ok, thanks Joe.
So then I'll definitely have the impedance but I might add an A/AB switch on the back just in case...

I might put up some pictures of my finished BA's if someone is intrested. Nothing special ecxept for the ABS-case. It's a plastic case from farnell for about 20€ :razz:

 

[Osse]

The Hybrid op-amp is based on the OPA2604, but what does the Hybrid Cirquit provide for the sound, compared to only the OPA?

 

[Osse]

Double post.