Sphere EQ 920 questions BST in/out?????????

I'm getting ready to rack my Sphere 920 eq's and the schematic is very hard to read(blurred), but I think I have most of it. I'm just confused over a term I've never run into before on the schematic.

Does anyone know what BST in and BST out could possibly be???

Here are the connections as I am reading them(or trying too, an unblurred copy would be helpful)

10 In +
L In common

9 +5v
1 5v ground

J EQ out

6&F +24v
5&E -24 v

B&D Ground

Does this look right?

Heres a link to the schematic

http://i158.photobucket.com/albums/t117/twist2002/sphere_eq_9.jpg

[quote author="Twist Turner"]I'm getting ready to rack my Sphere 920 eq's and the schematic is very hard to read(blurred), but I think I have most of it. I'm just confused over a term I've never run into before on the schematic.

Does anyone know what BST in and BST out could possibly be???

[/quote]

This is an extra gain block (it means "boost" I think) which is not needed if you want unity gain through the modules. On one of the models (930 I think) the "boost" level is controlled with a thumbwheel, so it could be useful for makeup gain if you're doing large cuts. I have the ones without the thumbwheel so I didn't hook it up. But you could put a 10k pot in between the EQ out and the "BST" in if you wanted to use that gain block.

Here's a pinout that I believe is the right one for your module, but don't try this without checking the schematic. The pinout varies for different models.

A - nc
B - BST out
C - gain out
D - Audio EQ out
E - -V
F - +V
H - BST in
J - EQ out
K - +5 V
L - EQ in

1 - logic com
2 - BST com
3 - Gain in
4 - audio BST out
5 - -V
6 - +V
7 - BST com
9 - NC
10 - com

Thanks for the info ytrehalf. I just got the par metal box and power supplies yesterday so this is going to be my project for next week. I'll check the schematic and see if your info looks correct. Mine has the thumb wheel on it, it is marked HP, I assumed this might be a high pass filter. I"ll try hooking it up without the bst and see what happens.

Note: I did take a look at the schematic, there are slight differences, so I'd advise anyone to check either of the pin outs listed above before hooking their device up. The main one was 9 is definetly labeled +5v on my schematic and K is labeled NC.

UPDATE: After looking at the circuit card I believe ytrehalf is correct, that K is +5v and 9 seeing how it just dead ends on the circuit card should be NC.

I have to figure out unlabeled transformers that came with them as well......

funny, most of your posts are questions about how to hook up some old junk you bought.

im gonna start calling you 'whats the hookup guy' :grin:

Since you consider my gear "Old Junk" I'm sure you wouldn't mind sending me some similar junk just to show what a nice guy you are then. :thumb: :grin:

Actually I have built quite a bit of gear, I've just been so busy in the last 2 years that about a couple dozen pieces of modules out of old consoles has been building up.

I have built from scratch:

1 ssl 4000 series compressor
3 LA2a's
4 Rca Ba2a's
and an entire recording studio in the last few years, including totally rebuilding all the modules in my Trident Series 80.

For now I've gotta get racked what I have before I build anything from scratch.

Next year I'm hoping to build a Redd 47 and a Pultec Eq and possibly a pultec mb-1.

In the last few months I have racked

2 Collins 356a-1's
2 Spectra Sonics 101 cards
2 TAB 74's
7 Siemens V72/V77 and V77b's
1 Universal Audio 1016
2 Calrec 1656 compressors
2 Melcor eq's
1 Emt 261 compressor
1 Telefunken U373a
2 Telefunken 395a's
2 Neumann U473's
2 Neumann W491a
1 Filtek MK3
2 Neve 3415's

Still to go:

Sphere 920 pair (this week!!!!)
I need to design face plates for 2 Cinema Engineering 4031 eq's (Today!)
Siemens U273
Pair of RCA BA71a's
Pair of Sphere M1200 cards

I can see the light at the end of the tunnel now. Soon I'll be making some stuff from scratch again.

Ok, got one ch. hooked up. This has to be the best sounding smoothest equalizer I've ever heard. Not bad for a piece of "old junk".

Heres the proper hook up info for anyone looking to hook one of these up in the future.

A - nc
B - BST out
C - gain out
D - 24v com
E - -V
F - +V
H - BST in
J - EQ out
K - +5 V
L - EQ in

1 - logic com (5v com)
2 - BST com
3 - Gain in
4 - audio BST out
5 - -V
6 - +V
7 - BST com
8 - 24v com
9 - NC
10 - Eq in com

Strap 3 & C

I did not use my jensen input/output transformers yet. It seems to sound fine without them. Although I'll most likely give them a try on Wed.

Thanks for all the help guys

Hi.

I have a pair of racked 930´s myself, and I agree, one of the smoothest and nicest eq´s I have heard.

First, the thumbwheel is a High pass filter and nothing else.

Second, the BST or booster amp was something that could be special ordered or not, there is space for it on the board but not always fitted.
From what I understand it is needed to be able to drive an output transformer.

Does yours have IC´s or are the all discreet??
I have a pair of 920´s as well that needs to be racked and they have IC´s on the input and output.
My 930´s are all discreet with booster amps and external transformers!

All discrete on mine. Yeah, I found out quickly what the thumb wheel does. I used it on a mix on vocals today and it sounded great as I expected, I'm gonna be using my Lang Peq2 alot less on vocals now. All I need now is the face plate back from front panel express and I'm ready to roll.