Official 33609 builder's tread. See 1st page for updates.

[tommypiper]

Congrats, Ultra-Alex, nice build! 

Ruud, congrats too!  I've been following your posts about the distortion as I'm hoping to start my build soon.  Thanks so much for explaining and looking into it so deeply and sharing your fix with us.  Can you post some photos to show how you added the mod?  I have to study this...

cheers,
t

 

[RedNoise]

Nice build...dunno if I prefer the Neutrik A2 or the 33609... ;D

 

[RuudNL]

I have improved the 'hold circuit' a little.
The MMV was not always triggered during a steady tone. The addition of a comparator improves this:

To demonstrate the effect, I have created a small MP3-file; the first five seconds are with the hold circuit, the following five seconds are without the hold circuit. The difference is obvious!!! Conditions: 5 dB limiting, 50 mS release time, 40 Hz.

 

[Rob Flinn]

Alex, where did you get the scales for your meters from ?  Did you buy them like that or print them off your self ??

 

[rob_gould]

Alex, where did you get the scales for your meters from ?  Did you buy them like that or print them off your self ??

Hi Rob,

www.sibalco.de is the place.  They are not cheap though!  If you PM me your email address, I'll send you the invoice with the part numbers on...

Edit :

Here are the part numbers - top line is the meters, second line is the illumination kit :

 

[StudioSQ]

I need info on hooking up the Marinair 1448 and 1442 to the 33609 board. I cant find a diagram that matches the pinout, nor can i find a schematic for either. Any help would be great, thanks! -J

 

[RuudNL]

I found the specs for the 1448 on the Internet:

T.1448 Line Bridging Transformer. Designed specifically to isolate equipment with previously unbalanced input arrangements, this transformer may be inserted without serious loss of level.
Rated impdances: 10,000/2,5000 : 9,600/2,400
Nominal Ratio 1+1: 1+1
Primary Pins 2-4, 3-5
Secondary Pins 7-9, 8-10
Screen pin 6
Rated max input: +20 dBm (above 40 Hz)
Distortion: <0.1% (above 40 Hz)
600 Ohm source, 9K6 load <0.01%

 

[RuudNL]

It seems the Marinair 1442 is the same thing as the Neve 31267: http://www.jlmaudio.com/Neve%20transformer%20info.htm (bottom of the page.)

 

[danjpiscina]

Hi guys. I want to build two of these. I'm finishing off a bunch of 1290 mic pre's from Martin and those were easy since there was a complete, accurate Bill Of Materials to go with it (most importantly they had Mouser and Digikey numbers, so for US DIY'ers). Does something like this exist for this project? A "standard" bill of materials with Carnhill tranformers and all the part numbers for the elma switches, etc.? Mnats 1176 still doesn't have one because the one that someone posted was riddled with errors so I ended up with a bunch of useless components. Partly my fault  ??? I'd like to avoid that since this is an expensive project. It's an investment.

P.S. What is roughly the total cost for US builders? Anyone have an rough number just to get an idea?

Thanks!

DP.

 

[playboss]

hi , im considering selling my untouched project /parts . I also obtained all the transformers (Chameleon labs) , only the output tx is gapped like the 2254c you only set a trimpot differently as it was discussed here.  Whats missing is the VU , I have all the elna switch (4x). Maybe I sell the chamlab iron elsewhere. Whos Interested? I get a lot of spam into my mailbox so pm pls.

 

[danjpiscina]

hi , im considering selling my untouched project /parts . I also obtained all the transformers (Chameleon labs) , only the output tx is gapped like the 2254c you only set a trimpot differently as it was discussed here.  Whats missing is the VU , I have all the elna switch (4x). Maybe I sell the chamlab iron elsewhere. Whos Interested? I get a lot of spam into my mailbox so pm pls.

PM'd you.

 

[playboss]

http://www.groupdiy.com/index.php?topic=26218.msg323118#msg323118

here s one of the BOM's , there are a few scattered around , doesnt mention some boutiqe parts tho, I told you bout those in my response.

 

[mkoz]

Hi guys!
Here will be posted info for 33609 builders.

.....

PCB's and cases were offered there.

http://www.groupdiy.com/index.php?topic=25172

This link is not leading anywhere. Could you please update the original post on the 1st page?

Thanks.

B.

 

[StudioSQ]

I found the specs for the 1448 on the Internet:

T.1448 Line Bridging Transformer. Designed specifically to isolate equipment with previously unbalanced input arrangements, this transformer may be inserted without serious loss of level.
Rated impdances: 10,000/2,5000 : 9,600/2,400
Nominal Ratio 1+1: 1+1
Primary Pins 2-4, 3-5
Secondary Pins 7-9, 8-10
Screen pin 6
Rated max input: +20 dBm (above 40 Hz)
Distortion: <0.1% (above 40 Hz)
600 Ohm source, 9K6 load <0.01%

is this the interstage? if so what is the hookup to the elco. are the sections in series or parallel? Help! also are the parts on the back of the board for 990 use only?

 

[danjpiscina]

http://www.groupdiy.com/index.php?topic=26218.msg323118#msg323118

here s one of the BOM's , there are a few scattered around , doesnt mention some boutiqe parts tho, I told you bout those in my response.

PM'd you again.

 

[StudioSQ]

I got my unit together but when i power it up the needle on the meter goes full on and never comes back. Unity gain in bypass, when I engage there is a 6db drop and the controls do nothing, this is true of both boards. any ideas? anyone else have this issue on startup?

 

[RuudNL]

The interstage transformer should be connected as 'step-up' (1:2). Maybe you connected it as a 1:1 transformer, this could explain the 6 dB loss. As a first step to solve the problem of controls doing nothing, I would measure the control voltage with the limit and/or compress threshold set to a low level. The voltage should change at different threshold settings.
(Of course: WITH an adequate input signal!  ;D )

 

[StudioSQ]

Ok my first problem is that right after r42 the 820 ohm in s3ereis with the power supply the voltage goes from 24v on one side to 14v on the other instead of 17. i tested the resistor and it is ok, i checked the bc184s and they seem to check out, AHH i am stuck

 

[RuudNL]

So: the buffer amplifier after the diode attenuator is drawing too much current.
First you should find out if this if caused by one, or both buffer stages.
Connect the Control Voltage line to the diode attenuator temporarily to ground.
Measure the voltage over R37 and R38, you should get something like 4,3 V. here.
(This would mean a current of 3,9 mA for each buffer, giving a total current of 7,8 mA,
7,8 mA through R42 (820) will produce a voltage drop of 6,4 V over R42, this is a normal value.)

 

[StudioSQ]

So: the buffer amplifier after the diode attenuator is drawing too much current.
First you should find out if this if caused by one, or both buffer stages.
Connect the Control Voltage line to the diode attenuator temporarily to ground.
Measure the voltage over R37 and R38, you should get something like 4,3 V. here.
(This would mean a current of 3,9 mA for each buffer, giving a total current of 7,8 mA,
7,8 mA through R42 (820) will produce a voltage drop of 6,4 V over R42, this is a normal value.)

Both resistors drop 5.8v