newbie first poster bearing gifts and seeking advice...
« on: September 14, 2004, 02:49:30 PM »
Hello all.  Very new to this forum, but I love it already.  Tons and tons of great info for the aspiring DIY'er. :thumb:

I finally got some time, energy, etc. and decided to take on my many half started projects.  This time, with a little guidance, I might be able to finish them.  And, of course, I have already started compiling parts for two new projects - discovered here - the ssl and the pultec.

I have plenty of spare modules I've been holding on to with the intention of racking yhem up and using them....instead of just looking at them in a box with various wires going everywhere - its depressing.

I figure to start easy and with the projects with complete parts:

Project #1:  4 Telefunken w695 (2x695 and 2x695a) eqs.  I have 2 in a 1u rack which requires them to be mounted horizontally - they are definitely more user friendly if mounted vertical.  I want to rehouse all four vertically in a 3u rack with a power switch, power indicator and in/out switches for each module with an indicator lamp.  While the in/out and indicator lamps are not essential, i will have plenty of space left on a 3u face for shiny knobs and lights (plus I found a local elec. store with awesome vintage indicator lamps).  I have a power 1 24v supply to power them.  I would need some help with creating a very simple diagram for the switches and indicators.  The lamps are bayonettes so I can use any voltage of bulb.  Also, i need help with distributing clean power to the 4 units.

Project#2:  Telefunken v372ds.  This is a stereo unit with big fat Hauffe transformers.  It is a line amp that can be modified to be a mic preamp.  I searched this site and found no info on this particular model, but I located the schematic.  Also, I spoke with someone about the modification and took some cryptic notes.  It was basically as easy as removing a resistor to gain access to the FB loop and sticking a pot there.  Anyway, he lives in Florida and is certainly dealing with not blowing away every week for the past few months from all the hurricanes.  Attached is the schematic (my humble contribution) as I did not see it in any of the schematic banks.

For this project, I intend to rack it up and add the basics - line/mic, phase, 48v, and -20 pad.  First, I believe I need a very clear and step by step instructions on how to modify this unit.  I will probably get the switches, pad, etc. from rollmusic.com

Project #3:  A really good one.  I have a vintage 50's military grade 3 ch tube preamp.....with a 4" vu meter that lights up!  It is very impressive looking.  It also functions well - after a good recapping - massive amounts of gain.  Problem is, the 3 input channels feed one output.  I would love to have each feed their own output.  Not a chance in obtaining a schematic, but it is all very beautiful point to point wiring so should be easy to trace.  I have some very good photos of the guts.  In its former life, it was intended to be a film projector audio preamp.  It has narrator inputs and a direct ot to the mixer.  It has a great deal of extra stuff that could be disconnected to stream line it a bit.  This unit was never used - I opened the box after it had been sitting on a shelf in some warehouse for 50+ years.

Project#4:  Telefunken 374a comps.  These are talkback limiters.  I had them racked up and used them for a while, but something was very obviously wrong.  I opened them up and saw evidence of some resistors burning and found one electro. cap that wasn't even soldered in!  Found the schematic here.  I would like to use these (I hear they work well for squashing loops) and if it is possible to make some mods, I'm all for it.  something like the std. comp. features - attack release make-up gain.  I also have good photos of the guts of this one.

I am pretty new to the DIY thing, but I am a very quick study.  I would love to be able to create some layout diagrams ala http://www.vacuumbrain.com/The_Lab/TA/Pultec/rons_eqp1a/eqp-1a_layout5d.jpg before I get started.  (that layout makes me believe I could actually do that project - standard schematics are greek to me as I have no background in electronics).  I look forward to any assistance in making my box of misfit modules into something useful.  If there is anywehere in the world to get help, it sure looks like this is the place.

Thanks much.

P.S. Couldn't figure out how to upload a .pdf of the 372ds schematic.  Where can I send it so that it gets posted?[/img]


newbie first poster bearing gifts and seeking advice...
« Reply #1 on: September 14, 2004, 07:39:22 PM »
I haven't read all of the above in full yet but I think I can see where this is going.

My suggestion is for you to start small with a single project that doesn't risk any vintage and worthwhile gear.
Probably not the greatest description there but stick with me.

We need to find what your skill level is.

Project #3:
looks tough but could be the best bet to start with.  You will learn here and you can use this to get best use out of Projects #1, #2 and #4.  With the Telefunken name you may find that you want to sell or swap to enhance one of the other projects.

set about drawing a schematic for these vintage 50's military grade 3 ch tube preamps and then put together a plan to use and rack them.
DIY Factory


newbie first poster bearing gifts and seeking advice...
« Reply #2 on: September 14, 2004, 07:47:53 PM »
I remember those three-channel projector mixer amps. There was a guy selling a bunch of those on evilBay a while ago. I was interested, but they were selling for more than I thought they were worth.


newbie first poster bearing gifts and seeking advice...
« Reply #3 on: September 14, 2004, 09:21:34 PM »
do you have metal for the 695's?  I had metal frames made for those , they screw right in.  I would just use an open frame 24 volt supply and buss all the modules together.  Thats how I had mine hooked up.  these are not of such intense fidelity that you need to go through the course of buffering power to all the modules, thats my opinion at least.  I would tackle that first.  All you need to do is wire the audio in/out, buss the power and hook it up to a readily available supply, get a power one at digikey for $50.


chips are good with dip...


Re: newbie first poster bearing gifts and seeking advice...
« Reply #4 on: September 14, 2004, 10:31:56 PM »
Quote from: "drummerman15"
P.S. Couldn't figure out how to upload a .pdf of the 372ds schematic.  Where can I send it so that it gets posted?

If you do some work and come up with some text and pictures to create a web page ... I'll give you the space.
If you do work as well as Kent or CJ .. ala the  vacuumbrain .. I'll even let you do a series of pages including the vintage 50's military grade  tube preamps ...

otherwise a place called photobucket is probably what you want.
DIY Factory


newbie first poster bearing gifts and seeking advice...
« Reply #5 on: September 15, 2004, 02:47:24 AM »
Thanks for the replies.

My skill level is about 4 of 10.  No formal or informal electronics training Good at soldering and simple repairs, but not so good with troubleshooting, theory/design or anything that requires the use of math.  If I have a detailed map or directions (not schematics), I can put it together.  

Actually Kev, I thought the tube project to be the most difficult to tackle and the 695s the easiest.  With the EQ's, i just need input, output and power -- that's no problem.  The problem there is incorporating the in/out switch with a lamp indicator and getting power to the indicator and power lamps.  I have a 24v supply for this project and know the pinouts for the 695, so, all parts are there, i just need the info on the lamp hookups.  Also, I have 4 eq's and I can get replacements from several sources.  I've only got one of those tube amps and want to be careful not to screw it up completely - better to have 1 output than none.  Also, the other Telefunken modules - the u374s and v372ds are not the most desirable units in the telefunken line and they were just freebies thrown in with the purchase of other stuff.  If they were v676's or u373's, I would definitely think twice about breaking them open and making modifications.  I use the tube amp regularly and these other modules are just sitting in a box and getting no use at all.

Maybe I'll give a shot at drawing a photoshop diagram like vacuumbrain's for the eq hookup and someone can tell me where I need to make changes.

soundguy:  For the 695's, I was going to have a panel made at front panel express.  Also, I have the 24v power one already - I guess I need to know how to correctly "buss the power"

newyorkdave:  I got it for about $200.  The "wow" factor to the clients when they come in and see a 4" vu meter is almost worth it.  People gravitate to that piece.  I would really like another unit (or a couple of direct outs on the unit I have) so i can send a B&O stereo ribbon mic through it.  Tons and tons of gain! [/quote]


newbie first poster bearing gifts and seeking advice...
« Reply #6 on: September 15, 2004, 05:01:51 AM »
Quote from: "drummerman15"
Actually Kev, I thought the tube project to be the most difficult to tackle and the 695s the easiest.  

... it probably is and that is part of the point.  Also no-one will care if you muck up a few unknown tube thingos.
It is very worth making a schematic of this.  This made lead to an obvious mod and method.  There is enough people here that will throw a ton of suggestions at you and any of them will be great.
DIY Factory


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