The Signal Transfer Company

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#323
PMA said:
HF linearity is not very nice, indeed

http://www.signaltransfer.freeuk.com/Class-GTHD1b.gif

How does it pass 19+20kHz test?
Click to expand...

It is worse than the Class-B Blameless, but that is a consequence of the extra wobbles in the output stage incremental gain due to the rail-switching. It is this rail-switching that gives the increased efficiency over Class-B. My design reduces the wobbles but does not eliminate them completely.

I am not aware of a Class-G design with lower distortion, if you are I would like to know more.

I don't do intermodulation tests as they yield little information.

Douglas
 
#326
Bonsai said:
I'm surprised you don't like IMD tests Douglas.

It's a good quick way to ascertain HF distortion. On my class A kx2-Amplifier, using an IMD test (19+220 kHz) I can easily show that TMC (or TPC) reduces HF distortion by c. 15 dB. You can of course do a frequency vs distortion plot, but the IMD is very convenient.

YMMV.
Click to expand...
But all you get is a bare figure saying you have so much distortion. With a THD test you can view the residual and get a good idea what the cause of the distortion is, eg crossover, slew-limiting etc etc.
 
#327
Class A CFA - no cross over and no slew limiting

🙂

I spend a lot 0f time on the simulator looking at distortion etc and once I have the design fine tuned go to build and then testing - SR limiting etc easily checked at the design stage.

I guess its about personal preferences and design workflow at the end pf the day - we all develop our own approaches.
 
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#331
Hi,
I was looking at the specifications for the amplifiers on the signal transfer site, but given the recent energy issues we are having in the UK, what is the idle power consumption for each of the amplifier designs ?

I am building a 3 way active loudspeaker design, and 6x the idle power consumption as opposed to 2x for a stereo amplifier is quite a difference in wasted energy.

Thanks and regards,
Shadders.
 
#333
(I have posted this elsewhere but have since discovered that this may be a more apt section to place it). Any help would be much appreciated.

Hello,

After some help sourcing parts please. Have bought the PCB from the Signal Transfer Company and require to source the parts for the switch banks. The information supplied with the PCB lists (I think) Signal Transfer Company's own part numbers and state that only they can supply. I have Emailed Douglas and he said that this would be altered. In the meantime, I need to obtain the manufacturer and their part numbers so that I can approach them directly for supply of same. Would appreciate any pointers you may be able to give on this.

I have since heard from from Douglas who has given me Gareth Connor's email address and stated that Gareth would be happy to supply the said switches. I have not had a reply to my Email to Gareth. I do not want to be left in a position whereby I have made a significant investment in purchasing the PCB and 737 transistors only to find that I cannot complete it due to either (a) lack of supply of physical switches from the Signal Transfer Company or (b) the manufacturer detail necessary in order to be able to approach the manufacturer directly.

Thank you


Neil
 
#336
I should have asked this first. Are you looking for switches for the precision preamp or the phono pre (Unbal or bal)? I don’t see that the switches are lit on the phono pre, which I have built and I don‘t own the precision pre.
 
#340
They have agreed to source the parts but I have not been given the part numbers. I don't blame them after all the hard design work and development......originally I was led to believe that I would have to obtain the parts myself......this turned out not to be the case.
 
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