JLM AUDIO

Hi Joe, does the JLM99V make a good summing amp? I'd like to use it in the CAPI 2-ACA for this purpose. I would remove the resistor following the op amp, so there is a cap in place to prevent DC from magnetizing the transformer. Thanks! Yes JLM99v if you isolate the DC offset like you mention works...

Hi...those VU meters are pretty small. If you are after a nice RTR or tape deck VU meter style, you may want to invest in a VU buffer PCB or kit and get bigger VU meters. I have used JLM Audio VU buffer kit and it works great. More expensive though than the Ebay one you have linked to. Realistic so...

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 ...

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 ...

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 cir...

Hey Joe, thanks for the reply. I did not mean to use the 6.3vac to drive the buffer. I thougth about using the B+ with a dropping resistor. And as a last resort I could use DC heaters and then thought about using this for the buffer. Thats why I ask if the supply voltage has to be well filtered for...

It will be this one but instead of the rectifier tube I will use diodes. I plan on using AC heaters but when that's too noisy I'll go with CR filtered DC heater. Due to the 6.3vac being centre ground 0v it will not work to drive the buffer. The CR filter DC heater will work if you ground 0v one sid...

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 p...

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.jlmaudi...

Hey Joe, I plan on building a tube mic preamp and would like to add a vintage Telefunken VU meter. I wanted to ask, what the best way would be to power the buffer from the power rails I have. The power transformer has 250V 20mA, 6,3V 700mA and 6,3V 500mA. I wanted to test AC heaters plus de-hummer ...

If i want to sum a balanced stereo signal to mono for inputing to the one of these boards, what's the best way? This would hang off the mix bus so wouldn't want it to affect signal. Do i need to add a buffer? Is the circuit attached overkill?balmix.jpg thanks That circuit will unbalance the balance...

Tardigrade Build Thread Notes and Errata First batch of pcbs have 1uF mono caps marked as C1 & C2 instead of correct C4 & C5. Tardigrade schematic http://www.jlmaudio.com/Tardigrade/Tardigrade%20schematic.pdf Tardigrade pcb to scale http://www.jlmaudio.com/Tardigrade/Tradigrade%20to%20scale...

Hey again Joe, Got to the calibration stage - the first side went well. Then got to the second side and had 1.67v output... after some investigation, I noticed I somehow missed installing a 100k resistor on the dingo :roll: That side is reading around 1.25v output now with 1.23v input (I assume thi...

Concerning the spot marked "case," I'm assuming this is the one and only connection to chassis from the power supply board. Can the AC mains earth ground still connect to chassis right by the IEC input connector like usual, or do I have to route it to this "case" spot on the pow...

Go Between RC Build Thread Below is the 2 most common wiring diagrams. With all relays operating on 48v or +/-24v max current draw is 18mA per GO between RC pcb + any LED or lamp current. Control voltage can be changed to 5v to 52v or +/-2.5v to +/-34v by 3 resistor changes and the 2 relay changes ...