BA BA2 BA4 BAD Dual99v Build Thread

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theaterguy
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by theaterguy »

Joe Malone wrote:
theaterguy wrote:Hi Joe!

Almost there, but I want be sure of some details before booting this thing (BA with JML14 + Hybrid + 315mA SMPS).

- #10k fitted and extra wire
- #BD681
- a small brown cap, reading "281". Where is this supposed to go? On a CLFixed I have "221".
- There was not a RG (68 ohm resistor) on the package, but I can get a substitute.
- one 27K resistor not found it's place.

thanks
Doesn't matter if #10k is fitted or not. BD681 not needed. Jumper C to E on both BD681 positions. Only 2 values of ceramic caps in the kit 47pF and 220pF so will be the 221 as 281 is not a standard value. The second 220pF is added to C Zobel and link to R Zobel only when using variable impedance. Extra 220pF not used with fixed 10k Rload. 27k is only used with OEP input transformer.
Joe, I'm bit confused. Doesn't the errata say that #BD681 must be fitted? Now I have all like in the errata, instead of that #BD681 there is a jumper and I have correct voltages.

There is another issue too; in the hybrid I first mixed 139 and 140 but I saw my mistake before powering the thing. Desoldering those was not the most pretty operation and could I have damaged them by heat, because I'n having occasional "gating" alike signal loss? Otherwise the unit gives nice'n' sweet sound.

mukole
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Joined: Tue Apr 24, 2012 4:03 pm

Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by mukole »

hi,
I received my ba4 kit yesterday and am very excited to start this project,
So far i have put together the in/out boards with xlrs, wired up the power section and built 1 ba with
a jlm14 onboard. It took me a while to get my head around the info on this thread,
but i managed to complete the board including the power mod, and all voltages test correct with and without the 99v installed.

I have several questions,

Should i have a second nut for the power switch included somewhere so that i can adjust the height of it to the front panel?

I have been looking over the BA2 and BA4 wiring overlay on your site and noticed i didn't have any white, blue or shielded wire,
I was wondering if i need to do this wiring as i do have the ribbon cables that would appear to connect the boards together,
If i do connect the inputs and outputs via the ribbon i'm guessing i wouldn't need the jumpers installed in the two channels i have
without DI's, is this correct?

And lastly, when i was assembling the in/out boards, i noticed there was space for a 10ohm, 2 x 6.8k's and an RLoad, I didn't receive any resistors in those bags so would i be right to assume they aren't require with my setup (no OP Transformer)??

Any help would be appreciated,

Regards,

mick

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Joe Malone
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Joe Malone »

mukole wrote:hi,
I received my ba4 kit yesterday and am very excited to start this project,
So far i have put together the in/out boards with xlrs, wired up the power section and built 1 ba with
a jlm14 onboard. It took me a while to get my head around the info on this thread,
but i managed to complete the board including the power mod, and all voltages test correct with and without the 99v installed.

I have several questions,
Ask all the questions you need while building either here or by email.
Should i have a second nut for the power switch included somewhere so that i can adjust the height of it to the front panel?
Yes should be 2 nuts in the power switch kit. If it is missing (as well as any other parts) just send me a email with name and shipping address (so I can cut and paste to our eparcel system) and list of any missing bits.
I have been looking over the BA2 and BA4 wiring overlay on your site and noticed i didn't have any white, blue or shielded wire,
I was wondering if i need to do this wiring as i do have the ribbon cables that would appear to connect the boards together,
If i do connect the inputs and outputs via the ribbon i'm guessing i wouldn't need the jumpers installed in the two channels i have
without DI's, is this correct?
Latest BA2 and BA4 kits use ribbon cables to connect the XLRIO pcb to BA and Fet DI. See Dual99v overlay for ribbon wiring detail. If no DI fitted the 2 pairs of solder pads under the BA PCB need to be soldered together where the jumpers would have been fitted in the 10 pin header otherwise there will be a hole in the input wiring.
And lastly, when i was assembling the in/out boards, i noticed there was space for a 10ohm, 2 x 6.8k's and an RLoad, I didn't receive any resistors in those bags so would i be right to assume they aren't require with my setup (no OP Transformer)??
Only parts in the XLRIO kit used. (NO resistors or capacitors are included in XLRIO kit as they are only used when we rack old vintage gear with XLRIO kit)
Joe :-)
JLM Audio
Capturing Audio without Injury

audioboog
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Joined: Thu Mar 22, 2012 2:48 am

Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by audioboog »

Hi again Joe.
Audioboog from Sweden here again. Building a BAD with Yamaha-parts(it gets really crowded on the card). We´re, me and my technician, having problems with our BAD. We can´t figure out the scheme. Everything works but it seems to be missing in gain, like its only working on one OP-amp. Sending some pictures with marks on.
Many thanks in advance
dual 1.JPG
dual 2.JPG
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Joe Malone »

audioboog wrote:Hi again Joe.
Audioboog from Sweden here again. Building a BAD with Yamaha-parts(it gets really crowded on the card). We´re, me and my technician, having problems with our BAD. We can´t figure out the scheme. Everything works but it seems to be missing in gain, like its only working on one OP-amp. Sending some pictures with marks on.
Many thanks in advance
If not fitting the output pot between the 2 opamp stages you will need to link O to I or there will be a hole in the audio path. The BAD has so much gain using a output pot is a good idea. See the Dual99v PDF overlay on the first post of this thread for BAD wiring details. The rest of the build looks ok. But I do not remember the yamaha input transformer colour code so that could be worth checking again. Also a good idea to check you are getting +24v on both opamp out pins to check they are working.
Joe :-)
JLM Audio
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ciscan.81
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Joined: Sat May 26, 2012 8:33 am

Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by ciscan.81 »

Hi Joe & Co.

I have nearly finished building my two BA's 99v with JLM14 inputs, FET DI, variable Z and JLM111 out. (40w 48v PSU). I really enjoyed the process, a great way to learn! I think I'll be investing in a couple more BA's to fill my rack sooner than I thought! :D

I think I got everything right, as I a spent a lot of time trawling the forums and trying to get my head around the schem and overlay.

I have tested the units, one at a time, with and without the opamp installed, with variable Z connected, gain pot disconnected, and FET DI disconnected . The values seem mostly ok but a couple do not match up with the overlay.

Please take a look at the photo of my test results (from below) and layout (from above).
BA Test results underside.jpg
IMG_0315.JPG
Please let me know if anything looks unusual.

A couple of things I wasn't 100% sure about that I'd like you to confirm:

1. Are the 0v readings, (circled in pic) I am getting around the input transformer correct because there is no ratio jumper used on the JLM14, and therefore they're not connected?

2. Is the 23.5v reading (circled) on the + side of the middle-left 470uF cap correct? There was no value given for this one on the overlay.

3. When using varialbe Z, I use both 220uF caps, one on CZ and one on CL and then put a wire strap across Rzobel. Correct?

4. I do not need to join pins 4 and 7 on DIP8 under opamp for this config, correct?

5. Is the slow falling voltage on the opamp IN- when the opamp is unplugged normal and caused by the caps discharging?

Again many thanks for your time and patience...

Cheers

Wayne.
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Joe Malone
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Joe Malone »

ciscan.81 wrote:Hi Joe & Co.


Please let me know if anything looks unusual.
All looks fine.
A couple of things I wasn't 100% sure about that I'd like you to confirm:

1. Are the 0v readings, (circled in pic) I am getting around the input transformer correct because there is no ratio jumper used on the JLM14, and therefore they're not connected?
Yes correct with JLM14 these pads connect to nothing.
2. Is the 23.5v reading (circled) on the + side of the middle-left 470uF cap correct? There was no value given for this one on the overlay.
Yes that is all fine. The main thing is that +in is around 24v and -in and out are roughly 24v when the opamp is fitted.
3. When using varialbe Z, I use both 220uF caps, one on CZ and one on CL and then put a wire strap across Rzobel. Correct?
Yes correct.
4. I do not need to join pins 4 and 7 on DIP8 under opamp for this config, correct?
Doesn't matter either way if using a output transformer.
5. Is the slow falling voltage on the opamp IN- when the opamp is unplugged normal and caused by the caps discharging?
Yes correct.
Joe :-)
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ciscan.81
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by ciscan.81 »

Man, that was quick!

Thanks for putting my mind at ease Joe, Happy Camper. :D

Now on to the 1290 and my 312-style BA!!! Hoorah!

ciscan.81
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by ciscan.81 »

Hi Joe

I have finished my two 99v BA's and my 1290, all looking good. Thanks again for all your help, apologies for bombarding you with all these beginner queries, I can only hope my lengthy posts will help other learners in the future!

My next build is my 312-styled BA. Specs as follows:

EA2622 input Transformer
SL-2520 (runs on 16V-18V)
EA2623-1 output Transformer
Variable Z
Output trim pot (doesn't need to do a lot of attenuation, maybe full pot rotation to deliver 10-20db?)
VU meter with buffer kit (have done the power on needle deflection reduction mod, and got your advice on providing correct voltages,, thanks)

I'm pretty sure I have the config. all worked out but would like you to confirm some values and answer a few queries below.

1. CL = NF
2. CZ = 220pf
3. RZ = 5k1
4. RL = 15k and 100k log pot

5. I have replaced the two 47pf ceramic caps with 220pf caps I picked up from Jaycar (are they of acceptable quality?) to match the 312 bandwidth

6. All Opamp Voltage Regulator # parts fitted including 33v zener.

7. Dual ganged output trim pot; I have 100k, 10k or 50k dual log pots, which do you think? Is there a formula to figure this out?

8. Is a ratio jumper required with the EA2622? I gather the most popular ratio is 1:7.

9. I read elsewhere
with the EA2622 you should wire the center two pins on the secondary side to the 0v ground under the pcb so the internal shields are working properly
Like this (pic below)? is there a shorter route?
IMG_0326.JPG
10. To connect the EA2623-1 output transformer 1:2, is this correct:

Primary 1+ (orange) to BA +OUT
Primary 1- (red) to BA Ov and XLR OUT pin 1
BA -OUT not connected (as per overlay?)
Secondary 2+ (Green) to XLR OUT pin 2
Secondary 2- (Blue) to Secondary 3+ (Black)
Secondary 3- to XLR OUT pin 3 (Brown)

EA2623-1 specs here http://www.classicapi.com/catalog/image ... -specs.pdf

11. VU Buffer then connects +IN to XLR OUT pin 2 and -IN to XLR OUT pin 3. Correct?

12. How do I connect the dual ganged output trim pot, like this (pic below)? And will this little-tacker from Jaycar handle the job? Rated Wattage: 0.05W-0.02W
IMG_0327.JPG
13. Will the output attenuator pot wired in this way have any strange effects on the VU meter and buffer?

Again, many thanks for your patience and taking the time to answer my questions :)

cheers

-W
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Joe Malone »

ciscan.81 wrote:Hi Joe

I have finished my two 99v BA's and my 1290, all looking good. Thanks again for all your help, apologies for bombarding you with all these beginner queries, I can only hope my lengthy posts will help other learners in the future!

My next build is my 312-styled BA. Specs as follows:

EA2622 input Transformer
SL-2520 (runs on 16V-18V)
EA2623-1 output Transformer
Variable Z
Output trim pot (doesn't need to do a lot of attenuation, maybe full pot rotation to deliver 10-20db?)
VU meter with buffer kit (have done the power on needle deflection reduction mod, and got your advice on providing correct voltages,, thanks)

I'm pretty sure I have the config. all worked out but would like you to confirm some values and answer a few queries below.

1. CL = NF
2. CZ = 220pf
3. RZ = 5k1
4. RL = 15k and 100k log pot
Yes correct.
5. I have replaced the two 47pf ceramic caps with 220pf caps I picked up from Jaycar (are they of acceptable quality?) to match the 312 bandwidth
yes good idea.
6. All Opamp Voltage Regulator # parts fitted including 33v zener.
Correct test between +v to 0v for 32v before fitting 2520 to check volt reg is working.
7. Dual ganged output trim pot; I have 100k, 10k or 50k dual log pots, which do you think? Is there a formula to figure this out?
Needs to be 500R or 1k max. Single or dual will work
8. Is a ratio jumper required with the EA2622? I gather the most popular ratio is 1:7.
Yes it 2 primary windings so low ratio will give 600ohm input with normal 15k load which is 1:3.5 ratio
9. I read elsewhere
with the EA2622 you should wire the center two pins on the secondary side to the 0v ground under the pcb so the internal shields are working properly
Yes correct the BA pcb has a square ground pad next to these two pins to wire them to 0v.
Like this (pic below)? is there a shorter route?
Yes the square pad next to were you started the yellow wire.
10. To connect the EA2623-1 output transformer 1:2, is this correct:

Primary 1+ (orange) to BA +OUT
Primary 1- (red) to BA Ov and XLR OUT pin 1
BA -OUT not connected (as per overlay?)
Secondary 2+ (Green) to XLR OUT pin 2
Secondary 2- (Blue) to Secondary 3+ (Black)
Secondary 3- to XLR OUT pin 3 (Brown)
Yes correct
11. VU Buffer then connects +IN to XLR OUT pin 2 and -IN to XLR OUT pin 3. Correct?
Yes correct
12. How do I connect the dual ganged output trim pot, like this (pic below)? And will this little-tacker from Jaycar handle the job? Rated Wattage: 0.05W-0.02W
Not like that. Just wire as a single volume pot between the output transformer and output XLR between +/- NOT to 0v
13. Will the output attenuator pot wired in this way have any strange effects on the VU meter and buffer?
Not if wired as a floating volume control
Joe :-)
JLM Audio
Capturing Audio without Injury

ciscan.81
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by ciscan.81 »

Right, Thanks Joe, glad I got it mostly right...

Take 2: So just to be painfully clear, output trim wiring pot like this for dual?
Dual Gang Output trim.jpg
or this for single
Sinlge Output Trim Pot.jpg
0v/pot pin 2 is left unconnected so the pot acts only as a variable series resistor, thus minimising the attenuation, yes? or am I way off again? heh :lol:
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Joe Malone »

ciscan.81 wrote:Right, Thanks Joe, glad I got it mostly right...

Take 2: So just to be painfully clear, output trim wiring pot like this for dual?

or this for single

0v/pot pin 2 is left unconnected so the pot acts only as a variable series resistor, thus minimising the attenuation, yes? or am I way off again? heh :lol:
Nope :D

Like below for dual 250, 500 or 1k log pot
Image

For Single 500, 1k log pot
Image

Both types perform the same due to the output transformer giving a fully floating output.

Best to keep total output resistance of pot or pots + resistor = close to 600ohm to keep the output impedance as low as possible. So single 500R log pot + 250ohm resistor = 750ohm or dual 250ohm log pot + 250ohm resistor = 750ohm

You can wire a dual 1k log pot in parallel to make 500ohm log pot. Resistor for 10dB range limit will be 1/2 of the total pot value. eg dual 1k pot = 2k / 2 = 1k. single 1k pot = 1k / 2 = 500. Make resistor smaller for more attenuation range.
Joe :-)
JLM Audio
Capturing Audio without Injury

ciscan.81
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by ciscan.81 »

Brilliant! Thanks Joe, I get it now. :D

Thanks again for your patience.

ciscan.81
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Joined: Sat May 26, 2012 8:33 am

Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by ciscan.81 »

Hi Joe

Just want to check a few test voltages with you for my BA 312-style before I fit the opamp

Specs:

EA2622 input Transformer (with middle 'LOW' jumper fitted)
SL-2520 (runs on 16V-18V) (not fitted for testing)
EA2623-1 output Transformer (not fitted for testing)
1. CL = NF
2. CZ = 220pf
3. RZ = 5k1
4. RL = 15k and 100k log pot (not fitted for testing)
replaced the two 47pf ceramic caps with 220pf caps
All Opamp Voltage Regulator # parts fitted including 33v zener.

Voltages: (all votages measured from 0v on back edge of BA PCB with phantom on)
BA312 Voltage Tests.jpg
I just thought the 20v and 10v readings seemed a little bit odd...

Also the SL2520 opamp I have does not have a 1/2V pin...is this ok?
SL2520 Underside.JPG
Finally a pic of my BA-312-style from the top.
BA312 Top.JPG
Many thanks again for your time...really looking forward to being able to post some pics of the completed units...nearly there! :)
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Joe Malone
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Joe Malone »

ciscan.81 wrote:Hi Joe


I just thought the 20v and 10v readings seemed a little bit odd...
This (if you have fitted the transistor the correct way around) is due to no current draw since no opamp fitted. If you fit a 4k7 to 10k resistor between +V and 0v on the opamp sockets you should get roughly the 32v as the Emitter as it can only be 1.2v lower than the base voltage of 33v when current is drawn.
Also the SL2520 opamp I have does not have a 1/2V pin...is this ok?
yes that is fine
Finally a pic of my BA-312-style from the top.
8) :D
Many thanks again for your time...really looking forward to being able to post some pics of the completed units...nearly there! :)
8)
Joe :-)
JLM Audio
Capturing Audio without Injury

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