It's correct. BCL2 schemo, LED meters on page 2.bruno2000 said:Would you please check your link?
Thanks!
Best,
Bruno2000
It's correct. BCL2 schemo, LED meters on page 2.bruno2000 said:Would you please check your link?
Thanks!
Best,
Bruno2000
Do you have any higher resolution pic by any chance?PRR said:It will be incredibly hard to beat the Neve 192 plan for cost and parts-count. Load the output with 1K, you get 0-1V for over 40dB of input range. Trim your '339 thresholds for the steps you like.
That's a dual supply design, isn't it?abbey road d enfer said:Look there, page 2
https://groupdiy.com/index.php?topic=49634.msg762968#msg762968
Almost textbook application, except R2 and R20.
Maximum voltage for these is only 16V but even if I overcome this issue I'm not sure how these can be set for -20dB to +28dB range.Bill Wilson said:For a 5 led meter this is what you want. KA2284/KA2285
No, single 24V rail.warpie said:That's a dual supply design, isn't it?
warpie said:Maximum voltage for these is only 16V but even if I overcome this issue I'm not sure how these can be set for -20dB to +28dB range.
Thank you for all your suggestions!
abbey road d enfer said:No, single 24V rail.
Yes I realise that. What I meant is I can't see how I can scale the LEDs on KA2284 so as the lower one will display -20dB and the highest +28db. I think they are "pre-scaled", if that makes sense.ruffrecords said:As I mentioned earlier, you simply pad the audio signal down so it falls within the range of the power supply.
Cheers
Ian
Correct, I had forgotten about the 15V regulator that was necessary to keep a stable reference.warpie said:On the schematic the LM339s are powered from +VD, which appears to be +15V.
YesBut they could easily be powered from a +24V rail.
That is correct. They provide other functions than LED meteing.However, the 4559 (1/2U4) and the TL072 (1/2U7) are fed with +/-15V.
I don't know. You wrote "I want a single rail is because I want to keep the LEDs separate from the audio rails." The LED meter I show works out of a single rail.Am I missing something? Most likely I am, so I should rephrase the question in "what am I missing?"
warpie said:Yes I realise that. What I meant is I can't see how I can scale the LEDs on KA2284 so as the lower one will display -20dB and the highest +28db. I think they are "pre-scaled", if that makes sense.
ruffrecords said:Ypu probably need to use a discrete comparator solution.
The full schematic is a limiter/compressor.warpie said:What is the purpose of the 4559 and the TL072?
Well, you have to find a way to rectify the voltage. Think how it was done with vacuum tubes, which were single-rail.As far as I can tell, If I use only the schematic on the 2nd page, the signal is not rectified.
warpie said:Yes, that's the "easy" part and I think I have figured it out. What puzzles me is to find an efficient way to rectify the signal with a single supply.
Still working on that though, haven't given up yet 8)
I answered this once before, in this thread...warpie said:Yes, that's the "easy" part and I think I have figured it out. What puzzles me is to find an efficient way to rectify the signal with a single supply.
Still working on that though, haven't given up yet 8)
JRsaid said:In general to perform AC functions (like rectification) from a single rail voltage establish a usable v/2 (12V). +/- 12v will handle most audio signals but perhaps incorporate -6dB in the input stage to prevent clipping.
I think I'm getting somewhere.
In the proposed schemo, there's absolutely no advantage in buffering Vcc/2, since it goes only to non-inverting inputs. However, this circuit needs smoothing in order to provide the correct ballistics; this would require additional circuitry that may require a stiffer Vcc/2.volker said:You can use the leftover opamp to buffer the 1/2 voltage. Tying it to one of the supply voltages isn't optimum, either use it as a buffer or put it somewhere between V+ and ground.
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