neve 33609 metal knob vs c/j/jd schematics

hey
i have a diy 33609j version. i just borrowed an almost impossible to get technical handbook for the very first metal knob version. and the differences are a lot (to any of the later versions). lots more tantalums in there. different cap values all over the place etc.
im not very good at reading schematics im afraid. but if any of you neve nerds is interested and able to post some results ill happily scan the documents. it would be great if someone would make sense of what changes were made - and what changes need to be done to get a j or j/d to metal knob. and share this with the community. im trying to do it at the moment - but im a little to inexperienced to deliver serious results. anyone in?

ps: also looks like the belclair transformers are surrounded by different components than with the marinairs. if we use carnhills i guess its all wrong to take the belclair schematics as a reference?

PM'ed you.

Mark

If it's not too much trouble to scan, I'd like to see the schematics. Could you post them? TIA!

now here is an easy list to revert j/d to metal knob for everyone interested:

1: change c19 (100pf) to styroflex and kill R54
2: kill c20 and c21
3: change c1 and c2 for 100uf 3v tantalum (most important)
4: change c6 to philips axial
5: change c23 to 470pf styroflex
6: kill r53
7: change r34 to 8k2
8: change r23 for 150 Ohms
9: if you want to go nuts change every 33uf cap for 10uf/25v tantalum in the sidechain
10: forgot some low value caps. replace them all with styroflex.....

im working with the standard jd schematic here... no guarantee for anything - please double check and dont blame me but (except for the sidechain) this is what i did. and it did matter to the sound in a good way (i think its c1 and c2 mainly).

honestly i think one will be fine by replacing c1&c2 (470uf elco) with 100uf tantalums. looks like the most important mod to me...

Cool stuff, I'll have to suss out the changes on the schematic.

Any chance you could post the older metal knob schematic?

Mark

Biasrocks said:

Cool stuff, I'll have to suss out the changes on the schematic.

Any chance you could post the older metal knob schematic?

Mark

Click to expand...

hey Mark
ill try to get my scanner running once im back from vacation next week. the mods i posted above did a lot to the sound imo.

hello salomonander,

do you have any succeeding thoughts about the mods you posted a while back?

I really appreciate you giving out this information, but I still feel a bit hesitant on performing these modifications on my original unit without having had a look at the respective schematics.

thank you so much, Marten

ok, I aquired some schematics from the 33609 J/D and C1 / C2 are the coupling caps to the interstage transformer. I presume changing these from 470uF/16V electrolytic to 100uF tantal will change the low end response and maybe the overall sound and I am about to give this a try!

For anyone looking at this, note that you will need a total of four of the 100uF tantals, as there are separate boards for each channel.

Keep us updated, Marten. I´m going to start with my 33609 Clone the next few days. Any infos about your mods are most welcome.

Jens, I had the caps for one channel and went ahead to modify it.
This way, I can easily compare and will do some listening to find out if I like the modification.
I also lifted the 600r resistors on the input, got some photos here.
If you want to check your build against "an original" I can lend you my j/d in week 2 and 3 of january, got a longer recording session where I won't use the 33609, no problem...

here a quick comparison on a programmed drum, A, B and relay bypassed (through the converters)

I can definitely notice a difference in overall feel and think I have my mind made up already!
will do more testing on mix 2-bus and vocals though...

33609_BYP.wav
33609_A.wav
33609_B.wav

Thanks for putting this up. Which version is track B? That´s what I like more.

to be honest: I have no clue
I kind of did that on purpose to avoid bias.
Will check tomorrow!

Marten, I am interested as well.

@ Jens: I have a few leftovers from my build... (Transistors, Labels for the Meters, etc.)... just drop me a line if you need something.
Pictures are here: http://twin-x.com/groupdiy/thumbnails.php?album=469

I am currently building a 2254 - all those variants of the boards drive me crazy! 

ok, ready for some confusion? 

It was hard to tell on the inside of the unit which pcb belongs to which channel (all XLR's go to relays) so I just went ahead and changed the other channel (middle PCB) to tantal caps. So I then re-recorded the audio files and was prepared to spot the obvious difference I noticed on the above posted files, except that: I can not tell which channel has changed!

So: there are two explanations:
1. my ears are tired for today
2. the channels themselves sound different and the tantal / ELKO thing is not such a big deal after all

I will try to get some files up as soon as my domain hosting company decides to fix my server... stay tuned

imho one nice mod on the 33609JD would be to "steal" the front panel attack switch from the limiter and "donate" it to the compressor section to be able to add a slower attack time. I find myself almost never using the limiter, but sometimes wish the compressor would let more transients through, but I am still in honeymoon with this comp so I'll see how I feel about that in a couple weeks.

Hi,
The metal power toggle switch on my 33609 (metal knob) unit has sheared off.
Anyone know which one I should replace it with? Very simple part but I'm crap at this!
CPC or RS links appreciated.