Recent content by ecc83

Hello David, I can add little to Rob's excellent treatise except to say I think you are unfortunately in a very high RF field strength area and fixing the problems is going to be difficult. Yes, ferrite absorbers on just about every cable and balanced cables everywhere. You might have to invest...

I would put serious money on that mixer having a Switch Mode Power Supply (my BCA2000 does) and so the 48V supply might be working but the +ve and -ve audio supplies failed. Does the FX display light up? You are I fear going to have problems getting that fixed. SMPSUs are notoriously...

Probably not mate. That pre amp "shoot out" came about partly I think because there were so many ding-dongs on their forum and others about whether expensive pre amps are really worth the money? The range of prices was I think about 10 to 1 and as I said, nobody picked out the expensive ones...

This might help, or not Rob! When auditioning monitors one of the most revealing tests is that of the human voice, notably is the listener 'fooled' into thinking they are hearing a real person. Problem: how do you make a perfectly faithful recording as a test piece? A measurement mic from the...

OK, LAST thing I wan ti is a cow with YOU friend but consider a "perfect" 1:1 ratio transformer in the OP stage of a mixer say? We expect and find, to a first approximation, the the frequency response is decently flat from say 40Hz to well beyond human hearing. Were the transformer behaving as...

Strictly speaking a transformer, when correctly terminated is not an inductor. This is how audio transformers 'can' give a flat, extended frequency response but beware! They are rarely perfectly driven or loaded and so are not totally' flat'. Transformers all have losses of course and one test...

I have always wondered what the design centre voltage actually was in the USA? Here I have read glib comments of anything from 110V to 120V with, I had assumed a 10% tolerance. Or is mains voltage set state by state? Frequency is held very precisely over here as well, a throwback to a time...

Number each mic and then draw numbers out of a hat for the sequence? And I know time is a bugger Rob maybe a gauze pop shield at a fixed distance and lips on that? A decade ago sound on sound did something similar with pre amps. The mics were a constant and the sound source a MIDI driven...

Better...definitely better maybe. Dave.

Be careful about "Old" phantom power! There were several systems developed and some might fork modern mics. One system relied on centre tapped transformers each end with a DC supply in the centre (AC ground) line. Of course, back in the day, virtually all pre amps had input transformers and it...

A good internet friend of mine who is an 'all knowing' retired guitar amp has told us many times that it was common for US amps to come here with 220,230 &240V tappings on their transformers. Taking our "normalized" 230V as gospel they set the amps for that and biased them accordingly. Shame...

Voltage tapppings of equipment such as radios and TV s were mandatory post WWll (at least in UK) because we had such a range of mains voltages around the country and even in different parts of towns and cities! (that's "private enterprise" for you!) Lowest was I think 200V and highest 250V. The...

You can ignore me all you like but that does not make you right. Torroids will not only run hot if mounted so as to form a shorted turn they will destroy themselves! Their main advantage in modern gear is that they allow a much lower profile chassis e.g. 1U rack gear. Valve power amps are SO...

As Popeye was oft'want to say "I's had all I can stand! I can't stands N'MORE! The variation in hum pickup in a guitar amp front end is FA to do with whether or not the valve has a grid stopper!! And there is nothing special about the TYPE of resistor used in that position. For most of their...

I am sorry OMG but how then do you account for this please...