Latest find...

Help Support GroupDIY:

iomegaman

Well-known member
Joined
Dec 21, 2008
Messages
656
Location
Tucson, Az
Biamp Legend Bimix...20/16 Mixer...($60.00 Craigslist including the power supply)

I know I know, it's starting to become apparent i have an old console fetish, but this one sorta took me by surprise...

The Amerimex sounded good when I could get it to cooperate, but it was a bit finicky and I still need to get a power supply that can manage the demands...

So this Biamp is a bit of a sleeper...the only issue with this board was the communications channel and I found a guy that sold me an OEM unit for $20.00...

Now I know Baimp does not really register in the "studio quality" of pursuable consoles but this one seems to be quite versatile and after going through the unit, the schematics and a listening test I am quite impressed.

This is a "2016" which means it is 20 channels in with 16 buses...yep 16 different bus channels available on every channel, they do this by using an opamp for the buffer as the pan control (to eliminate crosstalk)

Each channel has direct out, as well as a different sub out with its own volume control as well as the option to bus it to any/all of the 16 channels...channels 17/18 19/20 function as EFX or Cue channels for separate headphone mixes but it also has a control room output as well... its the most flexible board this size I have ever seen...which makes it perfect for a small studio environment...

I did some A/B testing to compare the discrete channel preamps with my Apogee preamps and basically they sound just as good but not as loud.

While it is a bit dated (lots of "tape input"stuff) it does provide some nice options because you can set up each channel to function as a direct Mic/Line in or with the push of a switch it goes to the tape input...

It is incredibly quiet, which kinda surprised me...the only thing that gets loud is when you turn on the power supplies "48v"  to power the board for phantom...the transformer for that part of the psu hums...the rest of the psu is passive cooled (and the 48v is a "soft delay" on the console...but even that is not that load I'm just a freak about noise because I'm in a smaller space...

Pretty happy with this purchase,,,saw in craigslist and researched it, found the schematic and figured it'd be worth $60 just to see how they pulled off the discrete section...

But now I have three consoles in a room not that big...I can see though that the Soundcraft and Amerimex will on get turned on for rare conditions...if ever.

 

Attachments

  • IMG_5407 (1).jpeg
    IMG_5407 (1).jpeg
    336.6 KB · Views: 67

iomegaman

Well-known member
Joined
Dec 21, 2008
Messages
656
Location
Tucson, Az
One other note, the schematics give a lot of modification notes, one of the primary modifications is adding an input transformer which Biamp originally provided if you wanted it...I'll attach the schemo if anyone is interested...pretty sound design, using 5532/TL071's...

The 3 band EQ is  not a Helios, but its a step up from the Soundcraft for sure.

Here's a link to the schematic if anyone is interested:

Dropbox Linky Do
 

fazer

Well-known member
Joined
Sep 10, 2007
Messages
1,499
Location
Elizabeth
Mic pres look like they will do the job.  Older consoles Achilles heal are switches and pots needing frequent cleaning.  Console looks like it is more accessible by modular design so that is a good thing.  How is the control room monitor section sound.  I prefer passive add on controllers for that function. 

Do you have a band you record.  Lots of channels to cover live ensemble recording.
 

iomegaman

Well-known member
Joined
Dec 21, 2008
Messages
656
Location
Tucson, Az
fazer said:
Mic pres look like they will do the job.  Older consoles Achilles heal are switches and pots needing frequent cleaning.  Console looks like it is more accessible by modular design so that is a good thing.  How is the control room monitor section sound.  I prefer passive add on controllers for that function. 

Do you have a band you record.  Lots of channels to cover live ensemble recording.

Yeah I have a plethora of DeOxit kinds of cleaning stuff....the one thing I am going through is it looks like perhaps something was dropped... 2 of the efx send pots on the master mix bus are broken and there's a handful of the dual gang pots that are bent...Mouser order will be here Friday...as far as the push buttons a good cleaning or two...

Just went through and calibrated the meter bridge only one channel was out of spec which is pretty remarkable...

The space I'm in at the moment is not really ready for a whole band...but its evolving.

And yes I already have a seperate passive monitor system...I just wanted to make sure all the channels connected would be back up to spec and load.
 

ruffrecords

Well-known member
Joined
Nov 10, 2006
Messages
13,771
Location
Norfolk - UK
Nice find. I am a sucker for downloading mixer schematics - thanks for posting them. I was interested to see they use a a Sharp chip for the VU drivers. Looks ideal for the job but unfortunately obsolete since 2005.
heers

Ian
 

iomegaman

Well-known member
Joined
Dec 21, 2008
Messages
656
Location
Tucson, Az
ruffrecords said:
Nice find. I am a sucker for downloading mixer schematics - thanks for posting them. I was interested to see they use a a Sharp chip for the VU drivers. Looks ideal for the job but unfortunately obsolete since 2005.
heers

Ian

I was not really excited about the meters until I used them (and later checked the calibration as well as against my Durrough)...

Pleasantly surprised at how much real "smart" went into this series...unfortunately Biamp went on to a different direction...but if you come across one of these they are plenty-too-much worthy of rescuing.

Does not seem to be any real info on what transformers they may have provided...the guy I got the communications module from pointed out that the direct outs on the cards were unbalanced...and he modded his to add the missing ring and a wire jumper to eliminate noise...downside is it throws off the metering when you switch from input to direct out levels...I guess because its adding a ground that the meter see's now...I dunno...I have lots of options to see what I'm recording and thats usually a distraction.

P.S. Ian there's a Sony MXP21 schematic in that same dropbox folder...nice little 8 channel mixer I have in the closet...my god I just realise I have 5 different mixers here...I might need an intervention.
 

ruffrecords

Well-known member
Joined
Nov 10, 2006
Messages
13,771
Location
Norfolk - UK
iomegaman said:
P.S. Ian there's a Sony MXP21 schematic in that same dropbox folder...nice little 8 channel mixer I have in the closet...my god I just realise I have 5 different mixers here...I might need an intervention.

Yes I noticed that!! Downloaded it too.

Cheers

Ian
 

boji

Well-known member
Joined
Jan 6, 2010
Messages
2,130
Location
Maryland, USA
Nice catch.  I was lusting after something like that before I took the diy plunge.  What are those bus selector switches called near the faders?
 

iomegaman

Well-known member
Joined
Dec 21, 2008
Messages
656
Location
Tucson, Az
boji said:
Nice catch.  I was lusting after something like that before I took the diy plunge.  What are those bus selector switches called near the faders?

Not sure which ones you are asking about...the two lowest push buttons are Solo (bottom) and Mute...


Here's a link to the manual that explains all of it....I will be honest, Biamps nomenclature on this console is a little bit unconventional...(the pdf with the pic of the console is the data sheet with the info)

Link to dropbox manual
 

cyrano

Well-known member
Joined
Sep 6, 2010
Messages
1,169
Location
Europe
iomegaman said:
my god I just realise I have 5 different mixers here...I might need an intervention.

Only 5?

I'd say you need a couple more .D

Looks like a nice desk. I've never even seen one. Wasn't aware BiAmp ever made mixers.

I have to tell myself not to buy any gear, just to save it from destruction. Too many gear, too little time...

I was very fortunate with my last acquisition, Was sold as "needs TLC", but the omly thing wrong with it, was that there was a ton of very sticky tape.
 

iomegaman

Well-known member
Joined
Dec 21, 2008
Messages
656
Location
Tucson, Az
cyrano said:
Only 5?

I'd say you need a couple more .D

Looks like a nice desk. I've never even seen one. Wasn't aware BiAmp ever made mixers.

I have to tell myself not to buy any gear, just to save it from destruction. Too many gear, too little time...

I was very fortunate with my last acquisition, Was sold as "needs TLC", but the omly thing wrong with it, was that there was a ton of very sticky tape.
Nice!...sometimes TLC can be reduced to just "C"...

The one thing I will say about a lot of the oldergear that is non-working is many times there are vintage parts etc...I picked up an old Urei Mod 1 used in a radio station (I suppose this might count as mixer #6!) with all the leads cut...but inside there were 8 UTC 012 input transformers (same exact ones used in the 1176) and several other output transformers besides the two big Original Vu Meters...cost me $50 to salvage vintage iron and meters as well as a lot of other parts...even if you can't restore it sometimes the purchase is worth it.
 

cyrano

Well-known member
Joined
Sep 6, 2010
Messages
1,169
Location
Europe
Yeah, I know...  8)

Didn't buy this one, but a mixer passed by on my radar with iron in it. 16 in 4 output trannies from the early seventies. Beat up from live use, sold as "Not working".  I was too slow. Sold for 50 euro. Shipment was far more...

I've seen too many desks go to recycling lately. A few months back, there was some desk in the skip at the local recycling park. Couldn't figure out what brand,

And the latest one I saved from that park, was already parted out. Just the VU's were still present. A heavy haul, both ways...  ;)
 

L´Andratté

Well-known member
Joined
Jan 17, 2013
Messages
684
Location
Hamburg Germany
Yes watch out for soundcraft series one from 70s-- 16 excellent 1:7 Sowters in it goes for like 200EU often!

EDIT: just looked there´s a very beaten up one for 1050EU on reverb,  well fvck that sh1t site :-X
 

Bo Deadly

Well-known member
Joined
Dec 22, 2015
Messages
2,632
Location
New Jersey, USA
Looks like ground canceling summing.

GroundCancelSum1.png
 

iomegaman

Well-known member
Joined
Dec 21, 2008
Messages
656
Location
Tucson, Az
squarewave said:
Looks like ground canceling summing.

GroundCancelSum1.png

Good eye, did not notice...without revealing my lack of schematic symbol interpretation, I wonder what the vale of R277 is supposed to be? Is it a situation where it is determined by loading it since even on the board layout there is no value given?

If I understand it correctly *277 is the "safety resistor" (DougSelf page 452)? It's value is not shown on either the schematic or the layout board...I'm replacing some pots on the mix module I'll track it down when the Mouser order arrives.
 

JohnRoberts

Well-known member
Staff member
Moderator
Joined
Nov 30, 2006
Messages
21,019
Location
Hickory, MS
iomegaman said:
Good eye, did not notice...without revealing my lack of schematic symbol interpretation, I wonder what the vale of R277 is supposed to be? Is it a situation where it is determined by loading it since even on the board layout there is no value given?
There is a legend (box) in the schematic providing the value of R277 for the different mixer models.
If I understand it correctly *277 is the "safety resistor" (DougSelf page 452)? It's value is not shown on either the schematic or the layout board...I'm replacing some pots on the mix module I'll track it down when the Mouser order arrives.
I don't see R277 in the truncated schematic so do not know what it is doing.

JR
 

Bo Deadly

Well-known member
Joined
Dec 22, 2015
Messages
2,632
Location
New Jersey, USA
iomegaman said:
Good eye, did not notice...without revealing my lack of schematic symbol interpretation, I wonder what the vale of R277 is supposed to be?
The table says "2016" is 820 ohms. I could be very wrong but my initial guess would be that the exact resistance of that resistor is actually kind of important to ground cancelling performance. It needs to match the impedance of the other input which is all mix resistors in parallel I suppose.
 

iomegaman

Well-known member
Joined
Dec 21, 2008
Messages
656
Location
Tucson, Az
JohnRoberts said:
There is a legend (box) in the schematic providing the value of R277 for the different mixer models.I don't see R277 in the truncated schematic so do not know what it is doing.

JR

Ahhh yes I stopped reading the legend at " * " (because I thought it was some schematic symbol I was not familiar with, it appears it is simply an asterisk)...so the legend tells us what each version of the mixer uses for that resistor based on how many modules...mine is the 2016/ so "820-Ohms"...

If I am reading it right R277 is the same as R6 in this diagram that D.Self calls a "safety resistor"

    "R6 is a safety resistor fitted in the aux master module so that it will keep working if the GC bus becomes disconnected."
 

Attachments

  • GC summing.png
    GC summing.png
    170.4 KB · Views: 8

iomegaman

Well-known member
Joined
Dec 21, 2008
Messages
656
Location
Tucson, Az
squarewave said:
The table says "2016" is 820 ohms. I could be very wrong but my initial guess would be that the exact resistance of that resistor is actually kind of important to ground cancelling performance. It needs to match the impedance of the other input which is all mix resistors in parallel I suppose.

Yes I think I agree...Self goes on to describe...

"The only
requirement is that R6 is high with respect to the total GC bus impedance so that the
subtraction remains accurate. If an aux send has an on/off switch that disconnects the mix
resistor from the bus, to minimize noise gain, the switch must also disconnect the GC resistor
to maintain correct cancellation."
 
Top