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Anything at 12VAC will do! The range of current rating is not important…. anything from 300 milliamps to 5 amps! Checking on CPC I see what you mean…. the only thing I could find on there was PW05886 which is a strange 11.5VAC output device. I’m fairly sure that would work OK; I can’t guarantee it but at that price it’s worth a try!
If you really need to! BTW, it’s not really ‘crosstalk’ between channels, it’s a function of the M/S system. In an earlier response on this thread I suggested that if you need a stereo system that is devoid of ‘crosstalk’ (which it isn’t really; it’s variations of the level of the difference signal) then this is not the right equipment for you.
For some inexplicable reason I did not see the last post on this thread until now….. The answer is yes, it’s pot luck if you get the good ones, but frankly at that price (and this is still the case) what have you got to lose?
The mics I have which operate from 48V phantom are definitely good for drum overheads… good pattern, wide response and good sound.
AS a further update (March 2018), We now have transconductance amplifiers (current mode, airDRIVE) in production and actually in stock at major retailers here in the UK! But, there is no ‘song and dance’ about it yet, we introduced a version of a new design of mine which succeeds in converting a class ‘D’ power amplifier into a transconductance amp. We put this amplifier into the ‘main’ signal path of our Orbitsound P70W loudspeaker, but without telling anyone!
The intention was to see if the Great British Public would spot the difference…. it is quite startling, and to gain experience with these amplifier types in production numbers.
The results are not exactly shattering….. the problem is that our airSound loudspeakers sound pretty good anyway and the improved fidelity, although really noticeable, can’t be discussed openly with the customer or we would give the game away.
So to round it off, what I originally called ‘airDRIVE’ is actually a version of a transconductance amplifier, modified to overcome a couple of foibles of the system, namely a tendancy to some nasty peaks at resonance and a naturally rising HF response. All Orbitsound P70W units have this amplifier.
It’s very likely that we shall introduce these amplifiers generally throughout future product ranges; the advantages are very real.
😮 The VC2 is similar in quality to the early VC1 channel amps except that the compression make-up amplifier is a tube. The tube stage is active all the time.
My experience has been that you should have no problems with the age of the unit as long as it has been kept in a reasonable studio environment, that is, reasonably dry.
I see a lot of these units coming back for servicing and they are invariably in really good condition, just with the odd scratchy pot and some physical damage.
regards
Ted
CAUTION!! 😯 The MQ1, unlike other JoeMeek units, is designed to work from 12VDC….. NOTE DC! If you connect 12VAC you will damage it!But nice to hear that you can appreciate the sound!
That mixer looks to be in remarkably good condition! Has it been kept in a museum?? You are right about the details; it’s a very simple mixer using all descrete components and because of that, it’s likely to sound nicely warm owing to the 2nd order distortion (It’s sad to call it ‘distortion’ because it’s actually an enhancement!)
I’m sorry that I don’t have any circuit details of the AD62, I designed it a very long time ago, but it should not be too difficult to trace the circuits.
It would be worthwhile to use a switch-mode power supply although you will have to add some smoothing. A 2,200uF cap with a series 1N4006 diode driving it should do the trick.
As for transformers, my advice would be to try them and see what works.
This was one of the microphone types that I was trying out after a visit to China to see the manufacturing plant at SE Electronics in Shanghai. I bought a small batch and tried them out in my own studio down in Devon. The ‘GP’ mic was very good, but very shortly after trying it, there were some business changes at SE and so I did not go ahead with it as a product line. It’s a perfectly good large diameter capacitor mic that I would use anywhere.
I do have one of those here and it can suffer from humidity problems causing high background noise. The fix is to keep it is a warm cupboard for a week or so to dry it out well.
Yes, the characteristics of compression are very similar to the VC1; it uses the same type of attack/release circuitry and the same optical cells. Different elements of ‘aggression’ are only very small variations in the settings of attack and release and the amount of ‘drive’ (input level). As a matter of technical interest to anyone else looking at the forum, one of the main reasons why these old optical compressors of mine sound so good is that during compression the 2nd order distortion (even harmonics) rises slightly, which has the psychoacoustic effect of making the brain think that the sound is louder than it really is. This is completely different to all other types of compressor where distortions stay the same or on some units, the 3rd order (unmusical) distortions rise; and they sound horrible! That, in conjunction with the shape of the attack and release curves, makes the compressor sound smooth and warm, even under severe (unrealistic) compression.
It sounds as though I’m pretending to be a Hi Fi anorak when I say that there are many factors in the operation of the optical compressor that are difficult or impossible to measure, mainly because they are transient effects of non-linearity not seen by the best measurement techniques, and certainly not reproduced with digital plug-ins!!
🙄 For those who might be interested, these ‘bricks’ were from a batch made in July 1996. There were only 10 units in that batch; the reason I remember it is that I used 6 of them for a location recording in August that year!