Search found 1557 matches

by Joe Malone
Fri Oct 18, 2019 2:26 pm
Forum: JLM Audio Kits
Topic: JLM99V as summing amp
Replies: 1
Views: 11

Re: JLM99V as summing amp

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...
by Joe Malone
Tue Oct 15, 2019 11:01 pm
Forum: JLM Audio Kits
Topic: Stereo VU meter kit BUILD THREAD
Replies: 41
Views: 39125

Re: Stereo VU meter kit BUILD THREAD

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...
by Joe Malone
Wed Sep 18, 2019 8:57 pm
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 333
Views: 259451

Re: BA BA2 BA4 BAD Dual99v Build Thread

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 ...
by Joe Malone
Thu Sep 05, 2019 10:50 am
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 333
Views: 259451

Re: BA BA2 BA4 BAD Dual99v Build Thread

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 ...
by Joe Malone
Wed Sep 04, 2019 9:37 am
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 333
Views: 259451

Re: BA BA2 BA4 BAD Dual99v Build Thread

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...
by Joe Malone
Wed Sep 04, 2019 9:32 am
Forum: JLM Audio Kits
Topic: VU BUFFER & PEAK LED KIT BUILD THREAD
Replies: 98
Views: 62543

Re: VU BUFFER & PEAK LED KIT BUILD THREAD

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...
by Joe Malone
Mon Sep 02, 2019 10:04 pm
Forum: JLM Audio Kits
Topic: VU BUFFER & PEAK LED KIT BUILD THREAD
Replies: 98
Views: 62543

Re: VU BUFFER & PEAK LED KIT BUILD THREAD

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...
by Joe Malone
Mon Sep 02, 2019 3:10 pm
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 333
Views: 259451

Re: BA BA2 BA4 BAD Dual99v Build Thread

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...
by Joe Malone
Sun Sep 01, 2019 10:10 pm
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 333
Views: 259451

Re: BA BA2 BA4 BAD Dual99v Build Thread

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...
by Joe Malone
Sat Aug 24, 2019 9:17 pm
Forum: JLM Audio Kits
Topic: VU BUFFER & PEAK LED KIT BUILD THREAD
Replies: 98
Views: 62543

Re: VU BUFFER & PEAK LED KIT BUILD THREAD

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 ...
by Joe Malone
Sat Aug 24, 2019 9:17 pm
Forum: JLM Audio Kits
Topic: VU BUFFER & PEAK LED KIT BUILD THREAD
Replies: 98
Views: 62543

Re: VU BUFFER & PEAK LED KIT BUILD THREAD

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...
by Joe Malone
Sat Aug 24, 2019 2:59 pm
Forum: JLM Audio Kits
Topic: Tardigrade Build Thread
Replies: 0
Views: 228

Tardigrade Build Thread

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...
by Joe Malone
Tue Aug 20, 2019 12:20 pm
Forum: JLM Audio Kits
Topic: MAC Rack kit Build Thread from October 2016 with slow attack led
Replies: 25
Views: 15535

Re: MAC Rack kit Build Thread from October 2016 with slow attack led

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...
by Joe Malone
Sat Aug 17, 2019 10:30 am
Forum: JLM Audio Kits
Topic: POWER PLANT BUILD THREAD
Replies: 19
Views: 17985

Re: POWER PLANT BUILD THREAD

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...
by Joe Malone
Fri Aug 16, 2019 10:34 am
Forum: JLM Audio Kits
Topic: Go Between RC Build Thread
Replies: 0
Views: 191

Go Between RC Build Thread

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 ...

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