BA BA2 BA4 BAD Dual99v Build Thread

[Camsown]

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

[Joe Malone]

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

Cool great to hear

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Thanks

[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

[Joe Malone]

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

[ajsteel]

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

Thanks for you help.

AJ

[Joe Malone]

Thanks Joe, do you think I could get one from an electronics shop? Just that the postage is more than the switch. 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.

[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!

[Joe Malone]

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.

[ylinjohto]

[/quote]

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.[/quote]

Opamp voltage is 24,1 and I guess that is ok because the Soun Skulptor sk99 is 24v op amp. I just need to clarify what exactly needs to be connected? 0V opamp socket to -output of the line output? Did I understood this correctly?

Thanks!

[Joe Malone]

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.[/quote]

Opamp voltage is 24,1 and I guess that is ok because the Soun Skulptor sk99 is 24v op amp. I just need to clarify what exactly needs to be connected? 0V opamp socket to -output of the line output? Did I understood this correctly?

Thanks![/quote]

If sk99 is +/-24v you want the reg linked over so you have +48v on +V pin as the BA uses this 48v as +/-24v but 0v is referenced to -24v.

[ylinjohto]

Hi, Thank you for information!

I was wondering what is the output impedance of the unit. With JLM14 input tranfo and NE5532A op amp. Does DOA change output impedance?


Cheers

[Joe Malone]

Hi, Thank you for information!

I was wondering what is the output impedance of the unit. With JLM14 input tranfo and NE5532A op amp. Does DOA change output impedance?


Cheers

Balanced output impedance with NE5532A or discrete opamp no output transformer using +out and -out is 102ohm if using 51R or 66ohm if using 33R.

[Vernois76]

Hey Joe, just got my BA kits in today. Just a quick question; on this version 2 you’ve added a trim adjustment for the opamp. Is there a setup necessary for standard 48v supply and 24v opamp?
Thanks for your time!
Gavin

[Joe Malone]

Hey Joe, just got my BA kits in today. Just a quick question; on this version 2 you’ve added a trim adjustment for the opamp. Is there a setup necessary for standard 48v supply and 24v opamp?
Thanks for your time!
Gavin

HI Gavin
For +/-24v opamps you can leave off the BD681 and still link E - C or just wind the trimpot to full. Either works fine. See the Ver 2 schematic under the photo of the new balck Ver 2 pcb for detail.

[papiblu]

Dear Joe,
cause Im a lazy bastard , I leave this unfinished Baby Animal in my garage for a couple of years.

It doesnt sound and I have no clue why.

Im sending you some photos, and maybe you find the problem

IM feeding it with the 48v of one of my powerplants that works perfect with other Pres.

Please let me know if you need some more photos

20210204_120521.jpg

20210204_114914.jpg

20210204_114842.jpg

Thanks in advance.

All the best

p.