New JLM 16v 99V

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AndyC
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Joined: Fri Aug 08, 2008 8:20 pm
Location: Perth WA

New JLM 16v 99V

Post by AndyC »

Hello all,

Thought it would be good to ask this question here so we all know.

The JLM sight says that old 99v's use +/-24v but work best on a higher supply up to +/-34v.

Now I have some of the new +/-16v 99v's and was curious if they could take higher supply rails or if +/-16v is the maximum supply?

Thanks

chrisp
Posts: 184
Joined: Sun Mar 04, 2007 11:46 am
Location: Sydney, Australia

Post by chrisp »

I'll let Joe or Mick answer directly, but ...

Bear in mind these are opamps, which means that the supply rails dictate the maximum output voltage (the amplified signal cannot exceed, and in practice will be a little short of, the supply rails).

So with the original 99V's, what's the difference at max gain between a 24V and a 34V supply? Answer: 20 x log (34/24), or about an extra 3db. So at 34V, the opamp max gain is something like 52db rather than 49db. Is that a difference you want to pursue by pushing the opamp that little bit more?

The 99V has plenty of sonic character without being pushed to its limits, so my preference would be to use the units as they were designed to be used.
Chris P
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I do lots of things. I believe eclectic skills are best.

AndyC
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Joined: Fri Aug 08, 2008 8:20 pm
Location: Perth WA

Post by AndyC »

Hi Chris,

Thanks for the info. I run the old ones of +/-24v at the moment and they do sound brilliant so not sure if I'll ever try this with higher rails for the older ones. The idea was more practical than sonic difference, I just read off Joe's site that the older ones work best at +/-34v.

Now if the newer ones (+/-16v) can run off higher rails then I can run them off the same set off rails as the ne5532 (+/-18v) instead of another pair of rails. This opens up a few options for me as I prefer (when possible) to run ne5532 on 18v instead of 15v.

chrisp
Posts: 184
Joined: Sun Mar 04, 2007 11:46 am
Location: Sydney, Australia

Post by chrisp »

I feel for ya! Multiple power supplies inside the one box can be a real pain.

My understanding is that the sound of the 99V does not really change with a higher voltage, just its headroom. I'll let Joe answer whether or not his 16v 99V can handle 18V!
Chris P
---------------------------------------------------------
I do lots of things. I believe eclectic skills are best.

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Joe Malone
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Post by Joe Malone »

HI Guys

Easy one 8)

Normal 99v will run on +/-24v to +/-34v.
+/-16v 99v will run on +/-16v to +/-24v.
Joe :-)
JLM Audio
Capturing Audio without Injury

frans
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Re: New JLM 16v 99V

Post by frans »

Errr... that would mean the +/-16v can go into my dual99v with 24v rails AND I could try it in place of the KDJ 4 in my purple action compressor? (lunchbox, +/-16v) and another Eisen audio pre, which also has the KDJ 4 & a JLM14 input transformer and a carnhill output...which I'm not that crazy about and wondering if the 99v opamp would make it as tasty and juicy as my beloved dual99v?
I have to keep this in mind when I place my next order from Joe. I wondered if the +/-24v I got currently would feel good in there, but I never tried it because I don't understand fully what I'm doing :? , maybe the poor 99v's will get starved.. :cry:

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Joe Malone
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Re: New JLM 16v 99V

Post by Joe Malone »

frans wrote:Errr... that would mean the +/-16v can go into my dual99v with 24v rails AND I could try it in place of the KDJ 4 in my purple action compressor? (lunchbox, +/-16v) and another Eisen audio pre, which also has the KDJ 4 & a JLM14 input transformer and a carnhill output...which I'm not that crazy about and wondering if the 99v opamp would make it as tasty and juicy as my beloved dual99v?
I have to keep this in mind when I place my next order from Joe. I wondered if the +/-24v I got currently would feel good in there, but I never tried it because I don't understand fully what I'm doing :? , maybe the poor 99v's will get starved.. :cry:
The only difference between +/-16v to +/-24v 99v and +/-24v to +/-34v 99v is the output transistors biasing. The high volts 99v will run on +/-16v volts but not as well/nicely as the greater biased low volts type 99v.

Remember if trying 99v in any other circuit designs there MUST be a output isolating capacitor to block the 1 to 2vdc output offset voltage on the 99v output pin or smoke may escape from the circuit and that is always bad.
Joe :-)
JLM Audio
Capturing Audio without Injury

frans
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Re: New JLM 16v 99V

Post by frans »

I'm glad that I asked! Thank you, Joe! I'll try and check the circuit of my Eisen pre and the action compressor to see if they got output caps. :D
Update: EisenAudio DIY500 MK1 preamp checked, C9, 470µF/16 bipolar. That should work.

moley1390
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Re: New JLM 16v 99V

Post by moley1390 »

Hi all, I was wondering if anybody knew what the current draw on these were? Also, is the consensus that the 16-24 would run fine on 17V rails, or should I really invest in a beefier PSU?

Cheers,
Scott

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Joe Malone
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Re: New JLM 16v 99V

Post by Joe Malone »

moley1390 wrote:Hi all, I was wondering if anybody knew what the current draw on these were? Also, is the consensus that the 16-24 would run fine on 17V rails, or should I really invest in a beefier PSU?

Cheers,
Scott
JLM99V Low Volts (+/-16v to +/-24v) is just a rebiased version of our normal JLM99V High Volts (+/-24v to +/-34v).

The JLM99V +/-16v to +/-24v will run fine on any voltage in between. So +/-17v is perfect.

The idle current draw if only 20 to 30mA no signal but can rise to 150mA driving rail to rail into a 75ohm load.
Joe :-)
JLM Audio
Capturing Audio without Injury

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