BAN Build Thread

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Joe Malone
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BAN Build Thread

Post by Joe Malone »

BAN Mic Pre
The Baby Animal Neutral super clean wire with gain 60dB single channel mic pre kit based on the Graham Cohen (National Semiconductor Designer) mic pre used in various forms by SSL, Neve Mozart, Amek 9098, Fred Forsell but made to work on a single 48v power rail.The mic pre has 20k input impedance which is perfect for not loading ribbon microphones. The PCB can take several input transistor pair types as well as several normal dual DIP8 opamps or discrete 1.1" opamps with standard 990 / 2520 pinout. A DI kit can be added in seconds with no wiring except one flat ribbon cable. This kit is even easier to build as no power supply has to be built.

Image

BAN Schematic here
BAN Parts List here

Notes & Errata
Note 1. The New 48v 520mA 25w MEPS SMPS external & 48v 315mA 15w internal SMPS power supplies under high capacitive and dc current power up surge can go into hiccup protection mode (power light will flick on and off) more easily than the old non MEPS ones so the below soft start mod is recommended for all new BA BAD BAN builds.

1. Do the soft start mod shown below. This leaves all parts fitted as normal but one track is cut and wire link added with #BD681 and #10k fitted. This gives 5 second soft start with no direct capacitance across the 48v SMPS and allows for the maximum possible BA BAD BAN combinations on one SMPS power supply. (#Zener is only needed as usual if opamp needs lower than 48v (+/-24v) rail.)
2. As always test each BA BAD BAN module on the 48v power one at a time without opamp fitted and test voltages and then with opamp fitted and test voltages to make sure the module is working properly. If one BA BAD BAN module puts the supply into hiccup mode there is a real fault.
3. While testing measure the voltage across the 10R resistor to see what current the BA BAD BAN module is drawing at idle (mA = V/10). Add up the total mA to check it is less than about 2/3rds of the specified current of the SMPS you are using to leave some headroom fro driving 600ohm loads.
4. Once all BA BAD BAN modules are tested to work correctly turn off and connect all the modules and power supply should powerup smoothly. If you are having problems email me with your exact configuration and which power supply you are using.

(Without mod each BA has 470uF and BAD abd BAN have 1000uF capacitance direct across the 48v rail which causes a short circuit for to long for the new MEPS SMPS)

BAN MEPS SMPS Soft start mod
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BAN Alignment procedure
Adjust 10k trim pot for half voltage at IC1 out socket measured from 0v. (usually 24v if no BD681 reg used)
Adjust 1k BAL DC trim pot so there is no DC voltage across the gain pot 2 wires at its minimum gain setting (pot at 10k)

The BAN PCB can take several options for Q1 & Q2 transistors with no other components changes needed.
2,4 or 6 x BC550C
1 or 2 x 2SK389
1 x LM394 (TO5 or DIP8 package)
1 x MAT02

IC1 can be normal DIP8 OPA2604AP for electronic balanced out or JLM99v, Hybrid, 990,992,993,2520 etc with quasi balanced out without a output transformer or fully floating balanced out with 1:2 output transformer like JLM111DC.

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Standard resistor values for making a switched RGain Control
RGain Value
20dB = 33k
21dB = 18k
22dB = 10k
23dB = 7k5
24dB = 5k6
25dB = 4k3
26dB = 3k3
27dB = 2k7
28dB = 2k4
29dB = 2k
30dB = 1k8
31dB = 1k5
32dB = 1.2k
33dB = 1.1k
34dB = 910
35dB = 820
36dB = 680
37dB = 620
38dB = 510
39dB = 470
40dB = 390
41dB = 360
42dB = 300
43dB = 270
44dB = 240
45db = 220
46dB = 180
47dB = 160
48dB = 150
49dB = 120
50dB = 100
51dB = 91
52dB = 82
53dB = 68
54dB = 56
55dB = 47
56dB = 43
57dB = 33
58dB = 27
59dB = 22
60dB = 18
61dB = 15
62dB = 10
63dB = 8.2
64dB = 4.7
65dB = 2.2
66dB = 0
Joe :-)
JLM Audio
Capturing Audio without Injury

greenmanhumming
Posts: 117
Joined: Tue Apr 10, 2007 1:19 am

Re: BAN Build Thread

Post by greenmanhumming »

I was lucky enough to get a Baby Animal Neutral from Joe recently, and I've built it and its great!

it has the solid mids I was looking for, its not over bright or harsh at all, and whilst it is very neutral, it lets the colour of the instrument come through, not "clinical" at all.

this has made me reassess my (slight) dissatisfaction with my other regular BA pres, its obviously not the caps, I'm now suspecting the transformers, and I expect I will try some lundahl LL1538s in the regular BA's when I can afford it, since I have had excellent results with those in my valve pres.

I have to disagree with Joe who says that the BAN are only suited for classical music or ribbon mics, I can definitely see close miced acoustic instruments in a folk/pop/rock setting being recorded on the BA Neutral.

I forgot to take pics before putting the case back in the rack, but next time I have it out I'll post a pic of the built board....

I'll certainly be ordering another BAN as soon as finances allow (and it appears in the shop)

greenmanhumming
Posts: 117
Joined: Tue Apr 10, 2007 1:19 am

Re: BAN Build Thread

Post by greenmanhumming »

my second BAN just arrived in the mail, thanks Joe!

heres a pic of the first one:

Image

greenmanhumming
Posts: 117
Joined: Tue Apr 10, 2007 1:19 am

Re: BAN Build Thread

Post by greenmanhumming »

when my fiddle player first listened to the BAN she said, "It's like it's not there"

yup, almost. I've not had another pre that even comes close to that.

Of course often we do want it to be there and affect the sound, but the BAN is great when you just want to hear the instrument (and the mic)

tenchijin2
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Joined: Thu Mar 12, 2009 1:15 pm

Re: BAN Build Thread

Post by tenchijin2 »

I would love to get my hands on a couple of these!!!! Joe, when are they going to be available?

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Joe Malone
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Re: BAN Build Thread

Post by Joe Malone »

tenchijin2 wrote:I would love to get my hands on a couple of these!!!! Joe, when are they going to be available?
BAN kit is available on the web store now at the link here
Joe :-)
JLM Audio
Capturing Audio without Injury

tenchijin2
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Re: BAN Build Thread

Post by tenchijin2 »

Very cool, Joe. Thanks! I have to get better at these so I can become a beta tester. I love testing gear.
Aric

Sylvain
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Re: BAN Build Thread

Post by Sylvain »

Excellent Joe!

- Can you (or anyone) offer up any thoughts as to what differences to expect with the use of different opamps and transistors? (Is that a MAT02 I see in the webshop picture?)

- Do you have schematics and a wireing overlay PDF available yet for the BAN?

- Do you offer the listed alternate parts on your website?


Sylvain :D

chrisp
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Location: Sydney, Australia

Re: BAN Build Thread

Post by chrisp »

Have I got this right?
BAN TRANSISTORS.jpg
If you use one of the matched pairs like the LM,2Sk or MAT or, do you need the trim circuit (2 x 2K2, 1K pot and 470u cap) or could this be omitted?

Also, with L1 and L2 (just behind the DI connector), you ignore the centre hole of the three on the PCB when using the kit supplied beads, yes?
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Chris P
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I do lots of things. I believe eclectic skills are best.

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Joe Malone
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Re: BAN Build Thread

Post by Joe Malone »

Sylvain wrote:Excellent Joe!

- Can you (or anyone) offer up any thoughts as to what differences to expect with the use of different opamps and transistors? (Is that a MAT02 I see in the webshop picture?)
PCB can take without any other part changes

1 x MAT02, LM394 in round and dip8 packages,
Image

1 or 2 x 2SK389, 2 or 4 x 2SK170.
Image

2 or 4 x BC550C
Image
- Do you have schematics and a wiring overlay PDF available yet for the BAN?
Almost finished the schematics etc. Will be in the first post of this thread as soon as they are ready.
- Do you offer the listed alternate parts on your website?
I have a small stock of 2SK389 but will probably offer 4 x matched 2SK170 and the 2 or 4 x BC550C as the extra cost of the 2SK389 and LM394 is considerable for this fairly cheap pre with no real improvement. Doubling devices can give up to 1 to 2dB improvement in signal to noise.
chrisp wrote:Have I got this right?
Yes cool drawing. Except 2 x 2SK389 can go in face to face as well. See above jpgs.
BAN TRANSISTORS.jpg
If you use one of the matched pairs like the LM,2Sk or MAT or, do you need the trim circuit (2 x 2K2, 1K pot and 470u cap) or could this be omitted?
You need the DC trim pot as it will trim the 1% resistor variation out. The 1k pot feeds the +V to the input devices and since the gain pot has no cap in series the DC trim needs to be set so at minimum gain setting there is no DC across the gain pot.
Also, with L1 and L2 (just behind the DI connector), you ignore the centre hole of the three on the PCB when using the kit supplied beads, yes?
Yes correct.
Joe :-)
JLM Audio
Capturing Audio without Injury

greenmanhumming
Posts: 117
Joined: Tue Apr 10, 2007 1:19 am

Re: BAN Build Thread

Post by greenmanhumming »

hmm, I have some 2SK170 what is the expected difference over the BC550?

how do I double the input transistors?

EDIT I tried some SK170BL, but they were very low gain.... something must be wrong..

chrisp
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Location: Sydney, Australia

Re: BAN Build Thread

Post by chrisp »

GreenManHumming wrote:how do I double the input transistors?
I've updated my chart to show the combinations - JLM will correct if I'm off beam.
BAN TRANSISTORS.jpg
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Chris P
---------------------------------------------------------
I do lots of things. I believe eclectic skills are best.

greenmanhumming
Posts: 117
Joined: Tue Apr 10, 2007 1:19 am

Re: BAN Build Thread

Post by greenmanhumming »

wow thanks, that is v clear.

though "In parallel" would have done

any idea why the sk170 fets didn't work right?

chrisp
Posts: 184
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Location: Sydney, Australia

Re: BAN Build Thread

Post by chrisp »

GreenManHumming wrote:any idea why the sk170 fets didn't work right?
I've just looked at the datasheet for the 2SK170 and from what I can see, the terminals are mirror image to the BC550C. You would need to rotate each of the transistors 180º compared to my diagram if this is in fact the case. Let me know if that works.
Chris P
---------------------------------------------------------
I do lots of things. I believe eclectic skills are best.

greenmanhumming
Posts: 117
Joined: Tue Apr 10, 2007 1:19 am

Re: BAN Build Thread

Post by greenmanhumming »

I'm pretty sure I tried them both ways round as I had the same thought but wasn't 100% sure. Will it damage them to it them in backwards? It seemed to work much the same either way around, I guess some fets are semi reversible anyway? I will try again to be sure tho

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