JLM AUDIO

So do you know that the led in the 34mm VU is 12volt, or are you assuming it is? Sorry - I should have checked that you are using the JLM VU buffer PCB. But Joe's thread quoted above does seem to indicate that it is 12V. I had planned to connect both in a string, since i have so much input voltage ...

LED If you want to run the LED on more than 12volts you will need to add a series resistor. Use this formula R = (V - 12) / 0.02. So if you have a supply of say 24v regulated the blue LED would need a resistor = R = (24 - 12) / 0.02 = 600ohm. So use 620ohm or 680ohm standard value resistor. Will ne...

Beta testers ? Me me me me me me me me me me me me me me me me me me me me me me Me me me me me me me me me me me me me me me me me me me me me me Me me me me me me me me me me me me me me me me me me me me me me Me me me me me me me me me me me me me me me me me me me me me me Me me me me me me me ...

Did he mention the JLM 24:8 bus mixing console in the interview? Or shouldn't I be talking about that yet....

No wait, that was like in my dreams, right?

(The MAC thread has some info on the new compressors, BTW - opto and fet in 500 series format)

Hi RMD The JLM 1:1:1 is very subtle in colouration, but I for one have no issues with that. But if you want colouration (bearing in mind that it is actually distortion) you should look at the DINGO opamp (a Hybrid is good here in class A if you want "warmth", and there's always the 99V) or any of yo...

For clarity........ Joe sells 2 types of Nissei meter. The 1U size 34mm small round VU Meter from Joe is NOT an AL29, and needs the two rectifier diodes at the bottom of the board. The AL29 is a larger rectangular meter and will not fit in a 1U case. This is the one with internal rectification where...

To add to Joe's reply, remember that the BA design is a single supply (48V+ and 0V) rather than a bipolar supply (24V+ and 24V-, with 0V sitting halfway in between). This makes the power supply easy, but to get any opamp to work with a single-sided supply, you add ("bias") the opamp + input with 1/2...

OR ..... SIGIN to 99V + 99VOut to SIGOUT and Rfeedback=10K and Cf=47p 99V- to Rf, Cf and 100uf electro anode 100uf cathode to Rser = 1450 ohms = 1k3 and 150R in series, and then to ground. My maths says that Gain = 1 + Rf/Rser = 1 + 10000/1450 = 7.8966 db = 20*log(gain) = 20 * 0.8974 = 17.95db (18db...

... and there I was trying to figure out how a capacitor somewhere might accumulate and discharge into the signal path ....

The trouble / strength of the BA is that it is actually such a simple signal path, and not much can go wrong with it once its working.

Sent you a PM

I assume you have a volume pot. How about variable impedance? any DI or meters?

I didn't know you were branching out from audio design, Joe!

http://www.jomalone.com.au

Welcome to the forums, tenchljin You've got the maths pretty much about right in terms of -20dbFS (or 2db either side thereabouts) = 0dbVU (an arbitrary number, its just a adjustment point on the VU) = +4dbu (=1.2V or so). As to whether a really hot signal at +16dbu (with the VU meter nailed to the ...

The Gyraf schematic to which you link in your first post states that you need to repeat the amplifier circuit for the other channel. So the Gyraf design uses two quasi-hybrids as well. I suppose the question is why go for the hybrid rather than just build it as per the Gyraf schematic. There main re...

It looks like the hybrid but with some components more in the surrounding circuit... Similar, yeah - you could use the Gyraf front end (C1, C2, R1, R2 and the volume P1) in front of a Hybrid and that should be fine. Both designs use high output transistors to drive the outputs. The only thing is th...