BA BA2 BA4 BAD Dual99v Build Thread

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Camsown
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Camsown »

Camsown wrote:Hi Joe.

On the Dual99v kits, where do I attach the phantom power led? Do I just attach it to the legs of the 48v toggle?
Also, the photo of the output pot wiring (on the first page of this thread) looks different than what is in the PDF for the Dual99v build. The pins on that switch look to be wired differently. Can you confirm that I should reference the PDF for these pins?

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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Joe Malone »

Camsown wrote:Hi Joe.

On the Dual99v kits, where do I attach the phantom power led? Do I just attach it to the legs of the 48v toggle?
Yes led solders to the top 2 legs of the 48v switch. Long led leg goes to the switch leg closest to the edge of the pcb.
Joe :-)
JLM Audio
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Camsown
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Camsown »

Hey Joe,
Should I follow the output pot wiring in the schematic pdf? Looks different from the image of it on page the 1st page of this thread.

Cheers.
Cam

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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Joe Malone »

Camsown wrote:Hey Joe,
Should I follow the output pot wiring in the schematic pdf? Looks different from the image of it on page the 1st page of this thread.

Cheers.
Cam
HI Cam the overlay pdf is the easiest to follow
Joe :-)
JLM Audio
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Camsown
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Camsown »

Hi Joe,

I've just found the time to finish the dual99v build. One channel sounds great. The other seems to be lacking volume. I can get a distorted signal from the effected channel when I turn the output up high but it tails away very quickly as I slowly back the pot off.

I've isolated it to being something on the preamp module or connected pots by swapping it with the working channel's preamp module. I've also swapped over the JLM99v opamps with no change to the distorted output on the affected module.

I've attached some photos of the module and pots. Any advice on what and how I should test from here?
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Last edited by Camsown on Sun Jul 14, 2019 6:25 pm, edited 1 time in total.

Camsown
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Camsown »

More photos
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Joe Malone
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Joe Malone »

check for shorts as shown in red.jpg
Check the pads in the red circle are not shorted together. Especially the 2 with the extra red circle around them
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JLM Audio
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Camsown
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Camsown »

Yep. That's fixed it.
Thanks for your help.

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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Joe Malone »

Camsown wrote:Yep. That's fixed it.
Thanks for your help.
Cool great to hear :-)

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ajsteel
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by ajsteel »

I need to replace the power toggle switch on my BA4 mic pre rack. What type of toggle switch should I purchase to replace the current switch? I couldn’t find a parts list.

Thanks for your help. Love these mic pre’s

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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Joe Malone »

ajsteel wrote:I need to replace the power toggle switch on my BA4 mic pre rack. What type of toggle switch should I purchase to replace the current switch? I couldn’t find a parts list.

Thanks for your help. Love these mic pre’s
Below is the switch we have made for us for the power switch kit.

http://www.jlmaudio.com/shop/large-toggle-dpdt-pcb.html
Joe :-)
JLM Audio
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ajsteel
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by ajsteel »

Thanks Joe, do you think I could get one from an electronics shop? Just that the postage is more than the switch. :D Are there any specs I need to look out for?

Thanks for you help.

AJ

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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Joe Malone »

ajsteel wrote:Thanks Joe, do you think I could get one from an electronics shop? Just that the postage is more than the switch. :D Are there any specs I need to look out for?

Thanks for you help.

AJ
Just DPDT large toggle 12mm mounting hole with 6 PCB pins. But I have no idea who would stock them as a standard part.
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ylinjohto
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by ylinjohto »

Hi!

I´ve got second hand BA-4 with NE5532AP Dual Opamps. The guy had ordered Sound Skulptor SK99 op amps but they were not yet installed. Are they straight drop in or do I need to make some modifications. At least I´ve got to get some pin soccets..
Here´s some pics from the current state of the circuit
down.jpg
up.jpg
I´m not very good at reading schematics but I´ve got decent soldering station and few successful builds on my sleeve.

Thank You!
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Joe Malone
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Re: BA BA2 BA4 BAD Dual99v Build Thread

Post by Joe Malone »

ylinjohto wrote:Hi!

I´ve got second hand BA-4 with NE5532AP Dual Opamps. The guy had ordered Sound Skulptor SK99 op amps but they were not yet installed. Are they straight drop in or do I need to make some modifications. At least I´ve got to get some pin soccets..
Here´s some pics from the current state of the circuit
down.jpg
up.jpg

I´m not very good at reading schematics but I´ve got decent soldering station and few successful builds on my sleeve.

Thank You!
Check the BA is fully working with NE5532A and input reg voltage is set to +30 to +36vdc on +V of the opamp sockets. If so you should be able to remove the NE5532A and fit 6 sockets and plug in the discrete opamp. Remember the discrete opamp is only driving the +out so link on dip socket is needed to put -out to 0v so quasi balanced out works.
Joe :-)
JLM Audio
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