Thanks Matt and Ike I'll try to take a closer look at it within the next few days. The console was recapped a little less than two year ago and has been functioning great ever since. So I'm inclined to say that is is unlikely related to caps. But a bad solder joint is definitely possible. I'll investigate that some more and continue searching for some transistors to have on hand.
I'll report back with my findings, Jared -----Original Message----- >From: Ike Zimbel <[email protected]> >Sent: Jan 26, 2010 2:55 PM >To: [email protected] >Subject: Re: NEOTEK: Mic pre transistors > >Hi Matt, > All of the documentation that I have seen says "factory selected" >on the 2SB737's, which are the only one of these transistors that I have >seen (or at least noticed) in a Neotek mic pre. Incidentally, I have >never seen one fail in a mic pre yet. Jared, I agree with Matt that you >should check all of the other components 1st, both for soldering issues >and value. Have the caps been done? >best, >Ike > >On 1/26/2010 12:36 PM, Matt Syson wrote: >> Hi Jared >> All or some of these transistors are approaching obsolete but should >> be obtainable by post from the internet. >> I would suggest getting a bag of them (they are not expensive) then >> you can match them using a multimeter for similar Hfe. >> (note, don't hold them for long as the finger temperature affects gain!). >> You could simply fit one and it will work but distortion would be >> reduced by matching. I don't suppose Neotek matched them originally >> though. >> It may be worth running the multimeter over the whole circuit >> comparing it to others (DC conditions) as there may be something else >> amiss. >> Matt S >> >> Jared wrote: >>> Hello everyone >>> >>> I'm having a problem with a series 1 mic pre (just the mic pre, line >>> in is fine). I'm getting a lot of noise and extremely distorted >>> signal. Everything looks fine visually. I swapped the chip and that >>> didn't fix it. My next thought was that it could be caused by a bad >>> transistor on the front end of the circuit. So I did a little looking >>> and now I'm a bit confused. >>> It seems that I need either of these transistors: 2SAB737, 2SA991, or >>> 2SA1084 >>> >>> I'm sure their are others but this is what is in my console and the >>> 2SA1084 was written in some of the documentation that I have. Does >>> anyone have a lead on where these can be sourced or other replacement >>> options? Also what is the best way to match them? Can it be a simple >>> DMM hFE test? >>> >>> Also maybe I'm going down the wrong path, any other thoughts about >>> what could be causing this? >>> >>> Sorry for the long post, >>> >>> Thanks, >>> Jared >>> ------ >>> >>> View the list online at: >>> http://www.mail-archive.com/[email protected] >>> >>> You can unsubscribe at anytime by sending an email to >>> mailto:[email protected] with "unsubscribe neotek" in the >>> message body. If you have any difficulties, or questions --please >>> send an email to mailto:[email protected]. >>> >>> The Neotek list is lovingly hosted by Catapult Web. Remember that any >>> message or reply sent to the list will be automatically forwarded to >>> all subscribers. >>> >>> Vive Le Neotek! >>> >>> Thanks. >>> >> ------ >> >> View the list online at: >> http://www.mail-archive.com/[email protected] >> >> You can unsubscribe at anytime by sending an email to >> mailto:[email protected] with "unsubscribe neotek" in the >> message body. If you have any difficulties, or questions --please send >> an email to mailto:[email protected]. >> >> The Neotek list is lovingly hosted by Catapult Web. Remember that any >> message or reply sent to the list will be automatically forwarded to >> all subscribers. >> >> Vive Le Neotek! >> >> Thanks. >> >> > >-- >Ike Zimbel >Zimbel Audio Productions Ltd. >Toronto >416-720-0887 > >"Studio House Calls". Authorized Warranty service for Allen& Heath, >Clear-Com, Drawmer, Soundcraft, SPL and Yamaha. Repairs and upgrades to analog >audio equipment including: AMEK, dbx, Neve, Neotek, MCI, Soundcraft and more. >Ask about our RF Frequency co-ordination services! >www.zimbelaudio.com > >------ > >View the list online at: http://www.mail-archive.com/[email protected] > >You can unsubscribe at anytime by sending an email to >mailto:[email protected] with "unsubscribe neotek" in the message body. >If you have any difficulties, or questions --please send an email to >mailto:[email protected]. > >The Neotek list is lovingly hosted by Catapult Web. Remember that any message >or reply sent to the list will be automatically forwarded to all subscribers. > >Vive Le Neotek! > >Thanks. ------ View the list online at: http://www.mail-archive.com/[email protected] You can unsubscribe at anytime by sending an email to mailto:[email protected] with "unsubscribe neotek" in the message body. If you have any difficulties, or questions --please send an email to mailto:[email protected]. The Neotek list is lovingly hosted by Catapult Web. Remember that any message or reply sent to the list will be automatically forwarded to all subscribers. Vive Le Neotek! Thanks.
