Hmmm - maybe you jest, but it sounds very like the 'Part P' building regulations recently imposed in Blighty. There are a few exceptions for the time being, but the aim appears to be to stamp out any
Maybe they've got you bugged? I reckon your sense of humour is one of the more valuable resouces here. Steve _______________________________________________ Amps mailing list Amps@contesting.com http
..And (a very big 'and') the SMPS means it will deliver full power and linearity when running from a generator, something that most valve amps (with cap input psu) fail to do unless the genny is way
And someone would get one heck of an earth mat! Steve _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
Measuring the heater current would likely prove it one way or another. It's worth doing tests both in and out of the amp if you can - that might show some oddity in the connections. Out of the amp, g
Usually it's blown from overload - the four diodes in the sampling gate and/or the p-channel fet go. There's a guy on ebay sells replacement kits. I haven't got round to repairing the one I have, but
I think any small shottky diode will work in the circuit. Without studying the manual, I'm not sure which characteristics matter most, but at I doubt there's any need for precision matching, if you b
Tom, if you haven't already been there, you'll find interesting reading in 'SSB principles and circuits', chapters 12-14 in particular. Steve _______________________________________________ Amps mail
No, if you're matching two resistances. If one or other end has reactance, then a three element matching circuit can (always, I think) give lower loaded Q. Steve _____________________________________
I disagree. I haven't time to try and remember how to do the maths, but looking at a Smith chart, I think a three element network can give a lower loaded Q if there is any reactance in either impedan
This is where I started - but you can always add a first element to take you to a pure resistance that's nearer your target than (say) R1 is. Then, the L match from the new resistance to target will
All this thinking is getting me confused. I'm back to my original conclusion. As an example, take an impedance of 100 + j50 ohms, which you want to match to 50R resistive. I can see two L match solut
CA2820 and 2830 are good ones, 0.5-1W capability and only a couple of power line decoupling caps needed. Motorola equilvalents are MHW590 and 592 - these replaced the TRW parts after Mot bought TRW.
Don't take that for granted! Depending on the levels, good generators with a good combiner should be ok, but I've seen people assume that and then spend time chasing problems that were in the source
In the data I have, only the FJ has IMD data in the specs - but it's at either 100 or 250W out, even if that's average power it's less than the tube is capable of. It reminds me a lot of the ratings
After more peering at Smith charts (considering matching some impedance to a resistance), I think there's some impedances where you can't get lower Q than an L match, and others where you can. There'
The STC data for 4CX250B gives typical values for class AB1: 2kV anode, 350V screen, 100mA Iq. 2 tone Po 325W pep, IMD3 -30dBc, IMD5 -50dBc. Same IMD at 1500V anode, 225W pep out. The power levels me
The data sheet is explicit in specifying the levels as relative to each tone. In my experience, STC brand 4CX250s do come close to this. There's a scanned version at www.g8wrb.org It's ok to referenc
I think it's important to consider the difference between the class AB biassing that we are all used to in our amplifiers, and true class A which is usually reserved for specialist ultra-linear requi
Yes - although IMD5 (or higher order) is rarely significant with class A amps running low IMD3. Very! It's a whole new world where driver stages are much bigger than you think they need to be. Say yo