okgb

Re: Anyone ever used a cloud lifter?
« Reply #20 on: August 01, 2012, 06:43:38 PM »
I'll buy a couple !
GKB Audio / Greg Boboski


pucho812

Re: Anyone ever used a cloud lifter?
« Reply #21 on: August 01, 2012, 07:10:29 PM »
You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is.

Rochey

Re: Anyone ever used a cloud lifter?
« Reply #22 on: August 01, 2012, 08:47:34 PM »
Is it a common design, or did a member of this forum design it?

I wouldn't want to step on someone else's toes without permission.

Then the q of resistors and caps... Do we need sumusu precision resistors, or will standard metal film do the trick?
Same for the 100uF caps... Fancy panasonics/muse caps, or run of the mill electrolytics?

Finally, I'm not a mic builder... What's the pcb size got to be below x,y and z.

Cheers

/R
Expat Audio Home: http://www.expataudio.com

okgb

Re: Anyone ever used a cloud lifter?
« Reply #23 on: August 01, 2012, 09:12:18 PM »
considering it is a balanced circuit , I would match the symetrical parts , resisters as close as possible
not sure where the point of diminishing return is but the common mode rejection is based on that, right ?
« Last Edit: August 02, 2012, 07:35:57 AM by okgb »
GKB Audio / Greg Boboski

Rochey

Re: Anyone ever used a cloud lifter?
« Reply #24 on: August 02, 2012, 12:14:47 AM »
I have 1% metal thick film in stock. Usually good enough... But I've been reading about folks who want specifically constructed resistors for audio.

Dave hill (from crane song) did some interesting research on the topic.

/R
Expat Audio Home: http://www.expataudio.com

mrclunk

Re: Anyone ever used a cloud lifter?
« Reply #25 on: August 02, 2012, 04:39:23 AM »
Think the circuit was designed by prr. (Check the thread i linked to earlier.) Or you could ask Rossi, he wrote a few articles about this type of circuit for a German electronics mag.

Resistors should be tightly matched. Use 0.1%. I suppose the caps should be too really. Caps should be as high quality as possible, i know nothing of smt so i can't help sorry...
The BJT's also need to have their hfe matched. There might be a dual packaged smd version tho with matched hfe already?
Otherwise i would probably keep the bjt's as a standard package and let the builder match them?

Be cool if the pcb could fit in a Male to female XLR barrel connector.
http://www.neutrik.co.uk/en-uk/accessories/circular-adapters/na3fm
« Last Edit: August 02, 2012, 05:00:13 AM by mrclunk »

Kingston

Re: Anyone ever used a cloud lifter?
« Reply #26 on: August 02, 2012, 09:53:17 AM »
Some important recap from the thread, more related to PCB design. With perfect transistor matching the caps can be omitted, but probably best use bigger tantalums there. Most people won't bother mathing. Even the suggested 100uF is available in SMD variants these days by the way. Should be transparent enough. The transistors are more of a problem. The one really good option is getting scarce: 2SC3329. There are available replacements but not quite as good. Less so in SMD format. Probably best provide a through hole option for the transistors and those two caps just in case.


Also, do not put anything inside barrel connectors people. In fact don't ever use them for anything. They are a worse idea than they look. It's only a matter of time before someone inserts them in an input slot and it sticks out really nice. Cue busy recording situation and some excited band member snaps the whole input slot right off, with the barrel still attached!
« Last Edit: August 02, 2012, 10:02:19 AM by Kingston »

Rochey

Re: Anyone ever used a cloud lifter?
« Reply #27 on: August 02, 2012, 10:03:02 AM »
I was thinking of the mat02/12.

The caps are a cOncern.  50v 100uF tants are nuts.
Expat Audio Home: http://www.expataudio.com

sr1200

Re: Anyone ever used a cloud lifter?
« Reply #28 on: August 02, 2012, 10:10:49 AM »
Quote
Also, do not put anything inside barrel connectors people. In fact don't ever use them for anything. They are a worse idea than they look. It's only a matter of time before someone inserts them in an input slot and it sticks out really nice. Cue busy recording situation and some excited band member snaps the whole input slot right off, with the barrel still attached!

Put it in line between 2 mic cables so this wont happen, ala shure sm98 or AKG 418's.  Worst that can happen then is someone steps on it and a scene from Home Alone is re-enacted in the studio.
MEI Studio - Long Island, NY: http://www.meirecords.com

mrclunk

Re: Anyone ever used a cloud lifter?
« Reply #29 on: August 02, 2012, 10:21:57 AM »
You want it located as close to the mic as pos, plugged straight in ideally.

Transistor wise,
I used 2N4401, there's talk somewhere of paralleling them for lower noise but i didnt.
« Last Edit: August 02, 2012, 10:41:54 AM by mrclunk »


Kingston

Re: Anyone ever used a cloud lifter?
« Reply #30 on: August 02, 2012, 10:29:41 AM »
Put it in line between 2 mic cables so this wont happen, ala shure sm98 or AKG 418's.  Worst that can happen then is someone steps on it and a scene from Home Alone is re-enacted in the studio.

Yes of course that's how you would use it if you were a professional. But like Y-cables - or anything that can be connected wrong - rest assured someday it will be connected wrong.

The caps are a cOncern.  50v 100uF tants are nuts.

50V? 16V should be enough. They are input caps. The voltage should be very low at that point always. Parallel with some nice ceramics perhaps, or at least provide an option for it.

Rochey

Re: Anyone ever used a cloud lifter?
« Reply #31 on: August 02, 2012, 11:08:17 AM »
I was under the impression the caps were blocking 48V.
Expat Audio Home: http://www.expataudio.com

Kingston

Re: Anyone ever used a cloud lifter?
« Reply #32 on: August 02, 2012, 11:12:07 AM »
I was under the impression the caps were blocking 48V.

Straight from the designer himself: http://www.groupdiy.com/index.php?topic=5743.msg618140#msg618140

also see zebra50's experiments with no input caps: http://www.groupdiy.com/index.php?topic=5743.msg502892#msg502892

sr1200

Re: Anyone ever used a cloud lifter?
« Reply #33 on: August 02, 2012, 11:20:20 AM »
So which would you recommend be tant and which electrolytic?
MEI Studio - Long Island, NY: http://www.meirecords.com

Kingston

Re: Anyone ever used a cloud lifter?
« Reply #34 on: August 02, 2012, 11:23:00 AM »
Use all tantalums. No worries with drying caps. No worries with SMD oven heat. The whole thing could then be implanted into a tiny epoxy clump with only I/O pins sticking out. Set and forget.

Kingston

Re: Anyone ever used a cloud lifter?
« Reply #35 on: August 02, 2012, 11:32:14 AM »
Just putting little brakes on. This kind of productisation of a design should be discussed with the original designer first and foremost, if it's ok to go ahead with it, compensation etc.

There are some mistakes in this area in this forums history.

Rochey

Re: Anyone ever used a cloud lifter?
« Reply #36 on: August 02, 2012, 11:34:19 AM »
agreed. (and I mentioned as much earlier in this thread)

just covering my ass  ;)
Expat Audio Home: http://www.expataudio.com

Rochey

Re: Anyone ever used a cloud lifter?
« Reply #37 on: August 02, 2012, 11:44:21 AM »
wait - hold the phone. this is just a long tailed pair amplifier isn't it?

Expat Audio Home: http://www.expataudio.com

okgb

Re: Anyone ever used a cloud lifter?
« Reply #38 on: August 02, 2012, 12:22:08 PM »
Won't be that hard to perfboard it either , just less convenient
GKB Audio / Greg Boboski

abbey road d enfer

Re: Anyone ever used a cloud lifter?
« Reply #39 on: August 04, 2012, 08:50:44 AM »
The caps are a cOncern.  50v 100uF tants are nuts.
These caps see a very small voltage, probably less than a few dozen millivolts. In fact only one is needed, unless one is anal about reverse voltage. With a standard floating mic element, only one of half the value is needed, and the lowest existing working voltage rating (1.8V) is amply sufficient. I believe PRR put two of them and spec'd them at 50V for protection in case of one of the transistors shorting. There are alternatives, if space is at a premium, like doing completely without the input caps and using clamping diodes at the input for protection.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.


 

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