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Hi Corey: I'd be OK with analog/manual switches and knobs, but you'd have to go co$tly if you don't want them to wear out. Figure this thing is not a set and forget device, people will be fiddling with the controls every time they put on a disk. That's a lot of hard use in a production environment. Also, I agree with Richard and Paul, that's the way to go with outputs. Richard's suggestion is perfect, just throw a set of RCA-to-TS adapters in the box. I don't think I included balanced inputs on my list, I agree with your point about them. I forgot if it was in this context or another that I said just use Henry Matchboxes if it's that critical. The only circumstance I can think of where it would be super-critical like that would be if you were looping through something like an old Pultec that really wants to feed a 600-ohm balanced device. -- Tom ----- Original Message ----- From: "Corey Bailey" <[log in to unmask]> To: <[log in to unmask]> Sent: Saturday, April 11, 2015 3:53 PM Subject: Re: [ARSCLIST] "Best of both worlds" disk preamplifier > Hi Tom, > > Thanks for bringing up this topic as I'm currently designing a restoration phono preamp for my own > use. I'm doing this simply because it's been awhile since I've built anything electronic or done > any board level work and I feel the need to scratch that itch. > > I'm basically going to build in everything on your wish list except for a couple of things: > > Unbalanced (phono) inputs only The only reason I can see for balanced inputs is for a line input > to the EQ sections (an outboard option I already have). Besides, to do this requires more > amplifier stages (even if unity gain) and I want to keep the active stages to a minimum. > > The outputs will be both balanced and unbalanced. > > You wrote: > <SNIP>”What I'd like to see built and marketed is a disk preamplifier that does the initial > impedence and capacitance match with the cartridge and the first stage of amplification, then > offers bridged output off that stage, goes on to do a passive EQ with all the turnover and rolloff > options, and then an output stage. So, a person could play a disk once (efficient workflow), make > a flat transfer to a separate digital file, and do the EQ to the best of their expertise and > taste -- so there is immediately a usable/listenable copy for researchers, library clients, > online, reissue or whatever. The idea of making two passes doesn't fit budget-constrained > workflows, and many of us are not at all sold on digital EQ (which also takes extra time and extra > steps after playback, again inefficient). The device I describe offers the best of both worlds -- > you get that flat transfer to archive and do whatever in the digital domain at some later time, > but you end up with a listenable/usable sound file at the same time.” <SNIP> > > I plan on building my preamp as a dual-mono piece of gear with a coupling switch that allows for > an EQ'd and Flat transfer simultaneously (or any combination thereof). Alternatively, it will have > RIAA EQ options and be able to be used as a stereo phono preamp. > > By “passive EQ”, I presume you mean an RC network in front of an amplifier stage. > > I'm still on the fence regarding impedance/capacitance matching for my own use because I only use > the usual “standard” cartridges. It's an easy add-on though. > > Regarding your “Dream Preamp” comments: > If you want to keep the end result as clean and as “esoteric” as possible (which I plan to do), > you avoid things like VCA's, relays and anything digital or even CMOS. It's only going to be hand > operated, gold contact switches and minimal amplifier stages. > > That said, I'd like to see more opinions and wish list features regarding this thread. > > Corey, > Corey Bailey Audio Engineering > www.baileyzone.net > > > > On 4/11/2015 5:46 AM, Tom Fine wrote: >> Does anyone know of any reviews of this unit similar to Gary Galo's testing of the KAB preamp? >> Maybe that's fodder for an ARSC Journal article -- a testing and features shootout between this >> unit, KAB, the LOC Preamp and the TDL Restoration preamp. Maybe throw in an old McIntosh or >> Marantz for comparison. >> >> One thing I'd love to see on my "dream preamp" would be a digital-logic control panel for the EQ, >> rather than rotary switches or pushbuttons. I'd prefer the audio to be confined to a PC board, >> where all the EQ components could be laid out with short signal paths, with routing done by >> little micro-relays or whatever they're using these days. And of course separate controls for >> turnover and rolloff. >> >> Calibrated precision output levels may be useful for some folks. I notice that the unit Parker >> distributes has VCA controlled outputs, which is a good idea. Using a digital-logic user >> interface could accomplish this with VCA's. >> >> -- Tom Fine >> >> ----- Original Message ----- From: "Parker Dinkins" <[log in to unmask]> >> To: <[log in to unmask]> >> Sent: Saturday, April 11, 2015 8:19 AM >> Subject: [ARSCLIST] "Best of both worlds" disk preamplifier >> >> >>>> Date: Fri, 10 Apr 2015 08:00:14 -0400 >>>> From: Tom Fine <[log in to unmask]> >>>> Subject: "Best of both worlds" disk preamplifier >>> >>> <snip> >>> >>>> The device I describe offers the best >>>> of both worlds -- you get that flat transfer to archive and do whatever in the digital domain >>>> at >>>> some later time, but you end up with a listenable/usable sound file at the same time. >>> >>> <snip> >>> >>> These preamplifiers have been available for some time: >>> >>> http://www.masterdigital.com/24bit/vadlydmd12.htm >>> >>> — >>> Parker Dinkins >>> www.masterdigital.com >>> >>> >> > >