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kryan1066 · Posted - Thu Jan 16, 2003 9:19 pm

Paul Stamler published a DIY Mic preamp a couple of years ago in Recording Magazine. Recently a few folks (including me) have become interested in trying the project out, but Paul ran out of his run of PCBs. He says he'll do another one if he can get 12 folks to agre to buy them from him. I think we have 4 so far. I don't remember how much he said he'd charge, but a similar project I did (Scott Dorsey's mic mod) required a $20 dollar cost for his PCB. Is anyone interested enough in trying this project?

Kryan

SteveG · Location: United Kingdom

I've heard stories about this mic pre, but I've never seen the schematic. I gather that it's not ridiculously cheap to build (like some published designs) - half of it is power supply, and you have to use the right Jensen input transformers. And I believe that you really need two boxes, in order to take account of this power supply! I don't know how it sounds, but since Stamler is reputed to have gone completely overboard with constant-current class-A stages, it should be pretty linear, which bodes well.

Quite frankly, I'm not about to buy 3 copies of Recording magazine from the USA just to have a look at the schematic, which is a shame, because I'd actually like to see what the fuss is about. If anybody fancies scanning the articles as jpgs or pdfs and sticking them somewhere I can download, I'd be well pleased. Any offers?

But as an encouragement to Kryan, I'd say that if you were interested in a project like this, then having the PCBs would be a major step forward to getting hold of what will certainly be a pretty high-class mic preamp. If you don't mind sourcing the components and a bit of DIY, this could be a good project.

kryan1066 · Posted - Fri Jan 17, 2003 7:07 am

Steve,

A very helpful person from the rec.audio.pro newsgroup heard the same plea from me about buying three mags that I already threw out years ago (made my brain hurt when I first saw it:)). He copied every page of the articles and put the schematics on CD for me. I don't know how easy it would be to put them on the web or anything, or even if Paul would allow that (copyright issues). But I'd be willing to help out here. To be honest, I just got the package in the mail and have not really gone through it in detail. But if I help out with the schematics, can I say I have another interested party?

Kryan/Ken

SteveG · Location: United Kingdom

Ken, check your mail...

VoodooRadio · Location: USA

Steve,
I subscribed to "Recording" mag for about 3 years. I don't exactly remember the start and stop dates, but I will look through them for the Paul Stamler DIY project. I'll let you know if I find them! Wink

SteveG · Location: United Kingdom

I think that the issues were the last three in 1998.

Ken is looking into this situation, but he says that it may take him a little while to resolve it, so any other offers of help with the articles in the meantime would be most welcome - then I can tell whether I'm game for this or not.

VoodooRadio · Location: USA

I researched alittle yesterday, and found one reference to Oct 99. I checked last night and I have back-issues from early 95 up to about mid 98. I will dig around some more and see what 98 issues I have. Shy

SteveG · Location: United Kingdom

According to their website, it's definitely the Oct, Nov and Dec 98 editions.

VoodooRadio · Location: USA

SteveG,
Here's the latest on the DIY project. YES, I found all 3 copies. I had a Lab Asst. photocopy all the pages. (21 or so) I'm not bothering with scanning and emailing. (too many) If your interested in a copy, email me and I will send it to you via good ol' snail mail. I'll even pick-up the postage!! Wink

kryan1066 · Posted - Fri Jan 24, 2003 5:09 pm

Thanks Steve,

I haven't been able to get around to it yet.

Ken

SteveG · Location: United Kingdom

Don't worry, Ken. I've emailed VooDoo...

VoodooRadio · Location: USA

And.... it's in the mail! Wink

zemlin · Location: USA

I'm not ready to step in the middle of this yet - I'd prefer to lurk a while longer, but I have nothing against DIY to save some money if this design is truly something useable for general purpose, high quality, digital recording.

Depending the complexity, cost, and what I learn following this thread I might be interested in two or more.

SteveG · Location: United Kingdom

At a bare minimum, this one gets added to a large pile of mic preamp designs that I've collected over the years. Some of them I've tried, some of them I've looked at and thought... well, I've thought quite a lot of things about them. There are loads of them available as schematics on the web, but they tend to be much of a muchness unless you dig around a bit.

There are one or two excellent designs about, like the Great River, but this needs work done to make it into a usable design - and there's no PCB layout or any advice, so you'd be completely on your own with it. But people say it sounds the business.

Interestingly, there are only a small number of design topologies that will actually produce quiet mic pre's, never mind good sounding ones. I've actually designed a couple of my own, but never had the time to optimise them fully, so they won't get published for a while...

But I have a pretty good idea of what is generally held to sound good in a mic preamp, and basically it's class A, differential throughout and highly linear. And as far as I can tell, that's more or less what Stamler is aiming at, so I have high hopes.

But there are issues. For instance, there are two schools of thought about whether you should use mic transformers - from a practical point of view, they are useful in noisy situations, because they can give you almost infinite common mode rejection, at least until the insulation breaks down! On transformerless designs, CMR is much harder to get right. But unless you use really excellent transformers, (the name Jensen springs to mind here, but they're not the only good ones) you are going to compromise the sound and the design rather more than somewhat, because you can't just whack a tranny on the front and have done with it.

But we will have to see. From what I can gather, there may be other advantages to his design as well...

jonrose · Location: USA

Just thought I'd throw in that I'm also curious about this design.

I haven't had a good "build" for awhile - and I think my soldering iron is quivering for a fix. Heh-heh!
;)

Anyway, I'd also be interested in any conclusions you guys have once you've all had a chance to sort through this a bit.

Best... -Jon

VoodooRadio · Location: USA

While admittingly not an Electronics Tech.... I did read the article and did have a look at the parts list. The project does use (2) Jensen 1:1 transformers (JT-11-BMCF) that cost about $97 each. This project won't be cheap in cost!! The parts list will add up to around $700 US! Of course the old adage... "you get what you pay for" definitely applies. As with most situations, those ET's that know distributors and suppliers, (as well as what parts can be substituted for others) will be able to put it together at a lower cost. Shy