The No.1 Website for Pro Audio
 Search This Thread  Search This Forum  Search Reviews  Search Gear Database  Search Gear for sale  Search Gearslutz Go Advanced
Chilton console appreciation...(with audio clip) Consoles
Old 31st May 2010
  #91
Lives for gear
 

...
Old 31st May 2010
  #92
RGB
Gear Head
 
RGB's Avatar
 

Thanks guys. So just the electrolytics...

I did also think about the filter section, I might as well do that too.

What about all those transformers in the master section? Is it worth changing those?

More to the point, how do you reach the master section?! I think I read somewhere that you have to get at it from underneath the mixer. Is this right? I haven't moved it yet to have a look underneath (need some extra hands to help lift it!)

Thanks for your help. (I am slightly jealous of the refurbished Chiltons in this thread, but I'm sure glad I have one. I'm still using the preamps on other channels whilst I work on the desk; amazing sound)
Old 31st May 2010
  #93
Lives for gear
 

Hi
The filters are in the meterhood, almost more important for a recap than the 'channels' as it wull be warmer up there. Maybe subtle, but it counts!
Matt S
Old 2nd June 2010
  #94
Lives for gear
 

...
Old 12th June 2010
  #95
Gear Nut
 

Recaping experience theory and practice...(long)

First, excuse my writing, english is not my first language, it might be a long posting but it "resumes" more then 25 years of professionnal analog mixer servicing in recording studios in Montreal, QC (North america's Chilton "capital") We had the north american Chilton distributor in montreal in the 70's, they sold a lot localy...


I'll share my experience regarding "recaping" audio mixers, specialy chilton QM3's, Amek, Westare soundcraft, SSL, Neotek, Neve and others...

There is one thing to take in account when dediciding to recap a mixer...
Is it a bypolar design (opamps) -/+15V or single supply design (usually discreet transistors in class "A" design)?

I have found out that, if you are recaping a single supply design you usually (ex:+24 volt) won't hear that "much" of a difference...as opposed to recaping a bypolar design console.

Why? There's a simple explanation, capacitor don't like to be reverse polarized. Even at low voltage for a long time...they simply don't age very well in that situation.

This is what you get on a bypolar design.
At the output of every opamps on a circuit, (Preamp,eq,filter,summing buss) there is a small DC offset that needs to be removed. This is the fonction of interstage capacitors (coupling capactors, the one that the audio will pass thru). In this kind of circuit it's hard to tell if the small DC offset will be positive or negative. Manufacturers don't realy know in what direction the polrarity of the capacitors should be.(and the "direction" can change as the console get's older) Any capacitor that as been exposed to a small "long term" revers voltage while get parasitic caracteristics. The capacitor will get resitive and inductive...(a ugly bandbass/all pass filter, that make the signal's phase go everywhere)

What about class "A" circuits?
In those type of curcuits all the interstage capacitors are polarized with real direct voltage. They are never exposed to reverse voltage, so they "age" more gracefully. This doesn't mean that they won't build parasitc caracteristics, but chances are that after more the 20 years, a lot of those capacitors are still not causing arm to the sound...

I have done the test myself on 8 QM3 Chilton preamps I have racked. I completly recaped one of the modul. Then, we did some "blindfolded" tests...
Comparing non-recaped modules and the recaped one...Nobody could realy pick the recaped one from the others...

MMMMMmmm! what does it mean?

In a unipolar Chilton (QM1/QM2/QM3) you have full Class "A" circuits
you might not need to change all the capacitors, especialy if they are Tantlium types (they look like small colored "drops"). Do one, then decide...
_____________________________
IMPORTANT MODIFICATION TO DO on any "QM" Chilton before recaping...
You will get "instant better sound", if you install filter bypass switches on each module. Because the low and hi pass filters are allways "ON" even if you put the pots in 20Hz/20KHz positions. Bypass them and you get FULL frequency response up the 50K... and down to 10Hz and less...
You can install individual swithes for the hipass and lowpass if you want

I will try to post pictures of my of 8 QM3 "parametric EQ" preamps in a "recycled Neve Prism" rack and my 24 input QM3... (unfinished project of merging two 12 inputs mixers)

Thanks

Daniel Benoit
Old 12th June 2010
  #96
Gear Guru
 
Karloff70's Avatar
 

^^^ Very good info post!! Thank you!!
Old 13th June 2010
  #97
Lives for gear
 

Hi
Picking up on a couple of things from Daniel.
If the circuitry uses ICs (TL072 or 5532 or 4) then they are not 'class A' unless they have extra 'pull up / down' resistors on their outputs to 'swamp' the 'inactive' transistor in their output stage. Having only transistors does not make it class 'A' either necessarily, you have to look at each circuit individually to determing it's mode of operation.
Secondly several manufacturers do either design in or make special provisions for polarising the coupling capacitors. SSL used to have 2 caps in series and 'pull' the junction between them to a supply rail, others deliberately allowed an offset so that the IC would naturally 'sit' at about a third of a volt or more in one distinct direction (only really possible with bipolar input devices). This would be done with a deliberately high value resistor biassing the input or another vession would be to pull them away from 'ground' with a high value resistor.
Matt S
Old 14th June 2010
  #98
Gear Guru
 
Karloff70's Avatar
 

Quote:
Originally Posted by Matt Syson View Post
Hi
Picking up on a couple of things from Daniel.
If the circuitry uses ICs (TL072 or 5532 or 4) then they are not 'class A' unless they have extra 'pull up / down' resistors on their outputs to 'swamp' the 'inactive' transistor in their output stage. Having only transistors does not make it class 'A' either necessarily, you have to look at each circuit individually to determing it's mode of operation.
Secondly several manufacturers do either design in or make special provisions for polarising the coupling capacitors. SSL used to have 2 caps in series and 'pull' the junction between them to a supply rail, others deliberately allowed an offset so that the IC would naturally 'sit' at about a third of a volt or more in one distinct direction (only really possible with bipolar input devices). This would be done with a deliberately high value resistor biassing the input or another vession would be to pull them away from 'ground' with a high value resistor.
Matt S
Thank you!!
Old 11th July 2010
  #99
Gear Nut
 

Hi Guys,

The time has come for our studio to upgrade and so the mint Chilton QM3 on page one of this thread is going up for sale.

The desk will be listed on eBay this evening and will run for a week.

The desk is advertised elsewhere too and so anyone interested in a purchase should email me direct on: [email protected]

It's been a pleasure helping out the many of you who have contacted me over the years regarding these wonderful desks and wish you all the best with the future use of yours. thumbsup
Old 15th February 2011
  #100
Lives for gear
 
Alexi's Avatar
 

hey blivetaudio,

have you sold your chilton?

I mght be interested if its still for sale.

cheers


alex
Old 21st February 2011
  #101
Gear Nut
 

Chilton was sold a while back folks,

Sorry.

B
Old 23rd March 2011
  #102
Gear Head
 

OK transformers... A client bought some of his Chilton mixer modules into me with transformer problems. I measured a good one. They are 5:1 ratio with an input impedance of about 1k5. A replacement that could be fitted with a few mechanical mods would be a Jensen JT-13K6-C. Same ratio and impedances with an improved spec. You will have to adopt the Jensen damping circuitry on the secondary. Change R10 for a 36k and R11 for 13k. C3 should be changed for 22pF. Use an NPO or COG type if you cannot get a polystyrene.
With regard to coupling capacitors on bi-polar op amps: They should be replaced with NON-polar capacitors. They are a little more expensive, but have a much longer life and do not suffer from reversed polarity problems. They can be got from RS and Farnell. Use 16 volt devices as they will take the full voltage swing. Tantalum beads should also be replaced to reduce distortion. Cyril Bateman wrote an excellent series of articles for Electronics World about capacitor distortion. The highest distortion of all caps was the tantalum bead. They are totally unsuited for audio and should be replaced as soon as you can!
Lastly, the NE5534 is an excellent op amp. Despite the poor press they suffer from, I cannot find anything worng with them. They have very low noise and excellent distortion characteristics. Bandwidth is excellent too. Just don't try to get too much gain out of them and they'll be fine.
Old 25th March 2011
  #103
Lives for gear
 
Alexi's Avatar
 

hi guys,

i am still looking for a chilton...
Old 25th March 2011
  #104
Gear Addict
 

Quote:
Originally Posted by Alexi View Post
hi guys,

i am still looking for a chilton...
Here is a chilton 16 ch. console for sale (its in norway, I am sure he will send it to you):

Musikkweb.no |
Old 20th April 2011
  #105
Here for the gear
 

Quote:
Originally Posted by Alexi View Post
hi guys,

i am still looking for a chilton...
Hey Alexi,

Did you find your Chilton? I am searching for one also, so I'm curious what you were able to find. How much, where at, what model, etc?

They must be good if no one is selling!

-Zack
Old 11th May 2011
  #106
Here for the gear
 

chilton

i used to own the 24channel that was being sold by Primal Gear, and currently have the 12 channel sidecar. i love it. the bigger one was in need of repair, the sidecar has 4 compressors as well. wonderful piece. occasionally needs some lovin but they all do
Old 3rd November 2011
  #107
Hi there guys...

I just received a Chilton QM1 12ch from a radionstation - they told me it was in their way...

Here is a pic:



The master fader panel is missing - was used to fix another in a neighboring country... I shall repair that by having a new panel laser cut from aluminum. Already contacted the local rep for P&G faders.

This desk is orientated for radio broadcast so I will carry out some mods to rig it for tracking & mixing use.

Its got a panel for 4 limiters but I see that the PCB modules are also missing. I have the schematics so I guess I can have new PCBs made... voila!









At least the channels are all intact!
Old 7th November 2011
  #108
Here for the gear
 

CM2 power supply

I've just recently chance upon a CM2 desk that was being thrown out of a university.

But the power supply has been lost! Does anyone know where I may be able to track down a replacment?
Old 8th November 2011
  #109
Lives for gear
 

Hi
They use 24 Volts for the main power rail and 48 for phantom.
Probably easiest and cheapest to get a 24 Volt 3 Amp or thereabouts Power One module and a 48 Volt 500mA module and box them up.
These desks do not normally need a huge amount of power as there are relatively few ICs in there. Fewer chips leads to less heat which leads to longer life. Combined with decent quality parts and they will last well.
Matt S
Old 10th November 2011
  #110
Here for the gear
 

Wow thanks for the quick reply!

I need some more info though :-( Here is a picture of the power socket:



It looks as though there are 7 electrical contacts. I read somewhere that it also requires a 12VAC feed. So the question I have is which power feeds go to which contacts?
Old 10th November 2011
  #111
Not sure Matt but I think the CM series work on +/- 15 volts... Am I wrong?

For sure the QM1 is +24 +48 though.
Old 11th November 2011
  #112
Lives for gear
 

Hi
I am happy to be incorrect in that it may use +-15 Volts.
It should not take many minutes to discover what voltage is required on the various pins on the connector by looking at the wires and find out where they go.
I would be a bit suprised if 12 Volts AC were used although possible for lamps or less likely if they had a transformer in there if it wanted a higher voltage supply.
Having AC going into any desk is a poor idea unless it is very carefully handled (for hum radiation).
Matt S
Old 13th November 2011
  #113
Gear Addict
 
Mo Facta's Avatar
Just got a CM2.

9 mic/line channels, 1 stereo channel, monitor and master section. Everything is in practically mint condition except phantom power needs a bit of a fix. Even the PPM meters work! The preamps sound great, too!

Cheers
Attached Thumbnails
Chilton console appreciation...(with audio clip)-chiltom-cm2.jpg  
Old 16th November 2011
  #114
Quote:
Originally Posted by Mo Facta View Post
Just got a CM2.

9 mic/line channels, 1 stereo channel, monitor and master section. Everything is in practically mint condition except phantom power needs a bit of a fix. Even the PPM meters work! The preamps sound great, too!

Cheers
Hey hey hey!
Old 20th November 2011
  #115
Gear Nut
 

Chilton QM and CM are two different mixer technology and sound...
Having used, serviced and modified both I can tell you the main technical differences.

QM1
The only "pure" discreet (transistor only)desing is the QM1. From input to output (preamp, EQ, filters, fader amp, summing and ouptut drive). Almost every thing is class"A" design. exept the final ouptut drive circuit that uses a "pushpull' configuration, using only transistors

QM2/3
I haven't seen any real QM2s, only QM3 with QM2 labeled pcb inside, I may be wrong but the QM2 was probably a transitionnal phase. They have an hybrid design they use discreet transistors in Class "A" in the Mic preamps, EQs and summing amps.
They use opamps in the filters, fader amps (+10db gain on each module), and output drives

CM
The use opamps every where (not in class "A"). The use bipolar power supplies (+/-15V)

All those consoles use SOWTER(and/or Belclere) transformers at the inputs (mic) and at the outputs (mix and groupes). this was a standard feature. As an option, line ins and all the ouptut (aux, CR, mono) could have transfos added for ($140/ch in 1980 money).

THE SOUND
So what about the sound...somethings to remember.
The all use transfos...
They all share a same design philosophy.

Lets say that the QM serie have a more distinct sound. Some say it's "dark" and silky...not to much headroom, bur realy nice. You can shape the sound buy using different working level. This is something that you dont get that much on other designs)

The EQ are realy nice, specialy the Parametric version, the are not "delicat and/or chirugical" but rather musical and efficient(almost like synth filter)

Headroom is not a problem when using single preamps and or direct outputs (it as 16 db of headroom)

Part of the sound is also caused by the good transfos...

In conclusion, I would say it's like driving a Ferrari, a MercedeS,or a BMW...it's a distinctive feeling, what model you have doesnt change the fact that you are having a nice experience. They are unique mixers with a nice "TONE/COLOR" and fun tools to work with.

I recently sold one of my QM mixers. a QM3 with all possible options, it was a dream machine...with all option on board: Parametric EQs, Bargraph VU's, transfos on all line inputs and output (aux, mono, control room, aux returns)and compressors The buyer was looking for somthing with a "TONE". He allready has 1073s, api, Great river preamps, Millenia's, chandler's little devil and other hi end gear.
I will miss her...

Daniel Benoit

PS: Mercedes yes, BMW yes, Ferrari not yet...
Old 22nd November 2011
  #116
Here for the gear
 
BrearneUpsero's Avatar
 

prikolizm

God , God , and he himself not be bad!
Old 22nd November 2011
  #117
Daniel, many thanks for a valuable resume! I'll take good care of my QM1!
Old 3rd January 2012
  #118
Gear Head
 

How about this one, It has two nice looking rtw meters as well, it's a c400, doesn't show any results on gearslutz....

anyone, looks quite old but cool, worth picking up, for a grand?
Attached Thumbnails
Chilton console appreciation...(with audio clip)-dff4maq-.jpg  
Old 3rd January 2012
  #119
Gear Head
 

Bump...
Old 4th January 2012
  #120
Gear Head
 

Anyone experience with this broadcastconsole, should i take the leap?
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Similar Threads
Thread
Thread Starter / Forum
Replies
RobAcid / So much gear, so little time
4
drockfresh / The Good News Channel
10
kbjazzman / So much gear, so little time
7

Forum Jump
Forum Jump