JLM99*MB Kit documentation

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frans
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JLM99*MB Kit documentation

Post by frans »

Hello,
I got a damaged JLM99*MB kit and I am going to repair it and put a second one into the box so the first one doesn't feel lonely.
So far it doesn't look too complicated for me, but I never had a formal training in electronics.
The one I got is fine so far, but the relays are dead. I could either ask Joe to pack me 3 more when I order my second kit, or if I get too impatient, try to substitute other parts. How about
http://cpc.farnell.com/nais/tq2-24vdc/p ... dp/SW02510
??? It's the DIL package, but I am not sure about the volts and all. Will these do the job?

Then I wanted to have a look at all the available information, but the following PDFs are blank and white, no matter if I open them in a generic viewer, Acrobat Pro, try to render them in Photoshop or open them in a vector based application like Illustrator. I also tried these PDFs from the old site, but to no avail: all white and blank. Has somebody got these lying around or any idea where to get them?

JLM99XMB.pdf
(Complete circuit of JLM99*MB with DC servo parts shown (DC servo not used for Dual JLM99v)
Dual 99v mic pre with JLM input transformer.pdf
(Circuit for Dual 99v with JLM input transformer)
Circuit of simplest 99V 60dB Mic Pre on JLM99*MB with transformer output.pdf
(Circuit of simplest 99V 60dB Mic Pre on JLM99*MB with transformer output.)
JLM99v with Output Trim or Fader and 5dB Switched steps.pdf
Circuit for Dual 99v with Output Trim / Fader & 5dB Switched Steps
JLM Dual 99v wiring overlay.pdf
(Wiring overlay for Stereo Dual 99v Everything kit)


I'm not in a hurry,

Thanks,
Frans from Bavaria / Germany

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Joe Malone
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Re: JLM99*MB Kit documentation

Post by Joe Malone »

frans wrote:Hello,
I got a damaged JLM99*MB kit and I am going to repair it and put a second one into the box so the first one doesn't feel lonely.
So far it doesn't look too complicated for me, but I never had a formal training in electronics.
The one I got is fine so far, but the relays are dead. I could either ask Joe to pack me 3 more when I order my second kit, or if I get too impatient, try to substitute other parts. How about
http://cpc.farnell.com/nais/tq2-24vdc/p ... dp/SW02510
??? It's the DIL package, but I am not sure about the volts and all. Will these do the job?
Relay type looks right except the need to 5v coil types. The 3 relays are feed by a constant current reg and coils are shorted out when switched off by switch. Which you will see when you get into the PDF's. Unusual for all 3 of them to fail so I think the problem is to do with power to the constant current circuit? Switch leds should still light even if the relays have failed. Do they? If you order a second JLM99*MB kit I would just add in 3 extra relays. If you are not sure why the relays are not working after looking over the PDF's send me clear large well lit in focus top and bottom PCB shot with opamps removed to my email and I will check the PCB's over for you.
Then I wanted to have a look at all the available information, but the following PDFs are blank and white, no matter if I open them in a generic viewer, Acrobat Pro, try to render them in Photoshop or open them in a vector based application like Illustrator. I also tried these PDFs from the old site, but to no avail: all white and blank. Has somebody got these lying around or any idea where to get them?
All PDFs on JLM new and old site work fine BUT you will need the latest Adobe PDF reader to view them. I recommend Adobe X reader for win 7. And then it is still best to download them to your computer and open the PDFs directly in the reader as your browser settings may also stop the PDF from opening.
Joe :-)
JLM Audio
Capturing Audio without Injury

frans
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Re: JLM99*MB Kit documentation

Post by frans »

Ah, the bloke who I got the 99 from said he accidentally crossed the wrong wires and then the relays were out. I desoldered them already as he did a bad job trying, one even was chipped. Now the board looks good again, checked for shorts, seems to be okay. The led lights okay, all power rails are fine. Yes, I think the best way would be to get these from you with an order, which shouldn't take too long.
I'd send pics, but last week my camera went dead and is a few weeks on repair now.
Joe, thanks for your reply and the PDFs ARE okay - the reader opens them fine. Duh! Why doesn't all my heavy artillery like Acrobat Pro open them properly? Scratching my head, but maybe got something to do with that you kinda locked your PDFs. Whatever, I can print them and that's what counts.

I got to mention that I've read an interview you did with Pan60 and the things you said about your opamp sold me - low gain, low damping. I don't know too much about electronics, but I think that transistors want to be in a topology like yours :D

frans
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Re: JLM99*MB Kit documentation

Post by frans »

Before I order I'd like to ask a question about the output transformers and the output trim. I've got a few transformers from Pikatron, ratio 1:2 in a mu metal can, the datasheet says source 1 ohm, load 300 Ohms, max 28dB @ 40Hz, THD 0,3%, 40Hz-15kHz +/- 0,3dB - they are big and heavy and look right to me for the job. If they aren't right I got no problems getting your 111DC.
Further I thought about the 60dB gain of the pre and how I rarely would need so much, how about if I install a switch that can "turn the transformer around", positition 1 on the switch: 1:2, position 2 reversing it: 2:1. Lower gain, lower output Z.
The output trim... I looked for 5k log pots with a switch (either 5k lin +switch or 10k log+sw)... didn't find any - maybe I could buy two from you?

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Joe Malone
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Re: JLM99*MB Kit documentation

Post by Joe Malone »

frans wrote:Before I order I'd like to ask a question about the output transformers and the output trim. I've got a few transformers from Pikatron, ratio 1:2 in a mu metal can, the datasheet says source 1 ohm, load 300 Ohms, max 28dB @ 40Hz, THD 0,3%, 40Hz-15kHz +/- 0,3dB - they are big and heavy and look right to me for the job. If they aren't right I got no problems getting your 111DC.
Sound like they would work perfectly.
Further I thought about the 60dB gain of the pre and how I rarely would need so much, how about if I install a switch that can "turn the transformer around", positition 1 on the switch: 1:2, position 2 reversing it: 2:1. Lower gain, lower output Z.
The Dual99v can do 80dB of gain but by changing 2 resistors this can be reduced to what ever range you want. Adding a DPDT switch allows you to have a high and low gain range for better control on the gain pot.
The transformer reversing idea will work also but requires a 4DPT switch and will give 12dB level change.
The output trim... I looked for 5k log pots with a switch (either 5k lin +switch or 10k log+sw)... didn't find any - maybe I could buy two from you?
We have 16mm dual 10k log pot with pull switch pot on the webshop for exactly this use. Can be wired as 5k log or 10k log.
Joe :-)
JLM Audio
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frans
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Re: JLM99*MB Kit documentation

Post by frans »

A little update: both of my dual99v are working fine and sound good - better than my vintage Telefunken V672, even though I have the best version they built back then. As long as both have headroom, they are good, when the V672 hits it can get ugly soon. The dual99v just handles it like a champ. If I hadn't a few good tube preamps the JLMs would reign supreme.
So I read on the web some Matt Moogus mentioned it would be no big deal to pop in some passive eq between the dual opamps where the output pot is connected - tasty!
When I'm going to build a few dual99v's more, I'll come back with a questions or two ... and have me a few channels of solid-state-Pultecs, kind of. :D

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Joe Malone
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Re: JLM99*MB Kit documentation

Post by Joe Malone »

frans wrote:A little update: both of my dual99v are working fine and sound good - better than my vintage Telefunken V672, even though I have the best version they built back then. As long as both have headroom, they are good, when the V672 hits it can get ugly soon. The dual99v just handles it like a champ. If I hadn't a few good tube preamps the JLMs would reign supreme.
Cool :D 8)
So I read on the web some Matt Moogus mentioned it would be no big deal to pop in some passive eq between the dual opamps where the output pot is connected - tasty!
When I'm going to build a few dual99v's more, I'll come back with a questions or two ... and have me a few channels of solid-state-Pultecs, kind of. :D
Yes a passive eq or our MAC opto comp can sit in between the 2 opamp stages on the dual99v and work perfectly without adding any extra audio path stages.
Joe :-)
JLM Audio
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frans
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Re: JLM99*MB Kit documentation

Post by frans »

Why not completely overdo it? I see a JLM channelstrip before me!!!
Like this: first stage of the dual99v - passive EQ network - second half of the 99v - MAC opto comp - Dingo kit - output. Maybe I could even take a 1:1+1 output transformer, pop it in between the 99v out and the opto input and have a second output without the comp plus some color? JLM channelstrip ... that would call for new thread :D

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Joe Malone
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Re: JLM99*MB Kit documentation

Post by Joe Malone »

frans wrote:Why not completely overdo it? I see a JLM channelstrip before me!!!
Like this: first stage of the dual99v - passive EQ network - second half of the 99v - MAC opto comp - Dingo kit - output. Maybe I could even take a 1:1+1 output transformer, pop it in between the 99v out and the opto input and have a second output without the comp plus some color? JLM channelstrip ... that would call for new thread :D
Yep that would work perfectly :-)
Joe :-)
JLM Audio
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baadc0de
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Re: JLM99*MB Kit documentation

Post by baadc0de »

Hi,

I'm putting together a 99*MB PCB (not a kit). I have a Haufe input transformer that is a LL*38 equivalent. I would like to use the board with two 990-style opamps in 2520 footprint without an output transformer (but balanced). As far as I understand, I want the DC servo option. That brings me to the choice of IC3 and the power supply for it. I would like to run the 990 opamps on 24V. I see there are some additional regulators onboard, so I thought 317 is used for 5V relays while the other two are for?? +- for IC3?

I would like to use this unit to record with ribbon microphones, so a lot of clean gain is desired.

Cheers,
B.

baadc0de
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Re: JLM99*MB Kit documentation

Post by baadc0de »

http://www.jensen-transformers.com/wp-c ... /as083.pdf

I see this "original schematic" says to use AD706 and seems to be using 15k as the resistor after the opamp. Maybe I could use OPA2604AP with +- 24V rails, the same as the discrete opamps will be using, so there should be no need for additional regulation on the board, just the one for relays.

Do you think I'll have to change any other values to prevent oscillation / other nasty side effects of using a high speed high voltage OPA2604?

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Re: JLM99*MB Kit documentation

Post by Joe Malone »

baadc0de wrote:Hi,

I'm putting together a 99*MB PCB (not a kit). I have a Haufe input transformer that is a LL*38 equivalent. I would like to use the board with two 990-style opamps in 2520 footprint without an output transformer (but balanced). As far as I understand, I want the DC servo option. That brings me to the choice of IC3 and the power supply for it. I would like to run the 990 opamps on 24V. I see there are some additional regulators onboard, so I thought 317 is used for 5V relays while the other two are for?? +- for IC3?
See complete circuit here. http://www.jlmaudio.com/JLM99XMB.pdf
Reg1 LM317 is the constant current for the input switching. Reg2 7815 and Reg3 7915 are IC3 DC servo IC which only needs to be a TL072 opamp. Link +OP and +S and wire to +24v power supply and link -OP and -S and wire to -24v power supply.

I would like to use this unit to record with ribbon microphones, so a lot of clean gain is desired.

Cheers,
B.
LL1538 is very clean and work well with ribbons for super clean recordings.
Joe :-)
JLM Audio
Capturing Audio without Injury

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Joe Malone
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Re: JLM99*MB Kit documentation

Post by Joe Malone »

baadc0de wrote:http://www.jensen-transformers.com/as/as083.pdf

I see this "original schematic" says to use AD706 and seems to be using 15k as the resistor after the opamp. Maybe I could use OPA2604AP with +- 24V rails, the same as the discrete opamps will be using, so there should be no need for additional regulation on the board, just the one for relays.

Do you think I'll have to change any other values to prevent oscillation / other nasty side effects of using a high speed high voltage OPA2604?
OPA2604AP is fet input like needed for DC servo but does not work very well in DC Servo tasks. The TL072 is way better at DC servo.
Joe :-)
JLM Audio
Capturing Audio without Injury

baadc0de
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Re: JLM99*MB Kit documentation

Post by baadc0de »

Thanks for the heads up. I can get the TI TL072ACP, I understand that's ok and within spec.

The regulators, as I see, will get me to +- 15V. Can I let IC3 work on +- 24V or must I always regulate that down?

Thanks :)

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Joe Malone
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Re: JLM99*MB Kit documentation

Post by Joe Malone »

baadc0de wrote:Thanks for the heads up. I can get the TI TL072ACP, I understand that's ok and within spec.

The regulators, as I see, will get me to +- 15V. Can I let IC3 work on +- 24V or must I always regulate that down?

Thanks :)
TL072 can only run on +/-18v max. So +/-15v is the ideal.
Joe :-)
JLM Audio
Capturing Audio without Injury

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