1DIFFQC amplifier

[OnAudio]

Hi Harrison

My transformer has arrived from Trade Me ( NZ E-bay ), it's a bit bigger than I thought it would be


1300Va

Output 1, 31volts @ 17.5 A
Output 2, 31volts @ 17.5 A
Output 3, 31volts @ 6 A

13.8 Kg's

No loss of power here ....but will need a soft start for this puppy!

That puppy is huge, sorry meant bull dog

 

[WSJ]

Not sure, how do you test the " no load input VA"?

Measure AC current and ACV with multimeter, V x A = VA.

The KILLAWATT a great power meter.
P3 - Kill A Watt

 

[Dagwood]

Thanks WSJ

I put a clamp meter on the phase last night and got,

0.7A x 230v = 161VA

Does that sound low?

I do know that when I fired it up on the variac without winding it back to 0v first it blew the fuse straighht away! hence the soft start!!

 

[WSJ]

Thanks WSJ

I put a clamp meter on the phase last night and got,

0.7A x 230v = 161VA

Does that sound low?

I do know that when I fired it up on the variac without winding it back to 0v first it blew the fuse straighht away! hence the soft start!!

I measured my ALESIS RA150 amp at 66 VA, no signal.
4 ohms: 75 watts RMS per channel.

For the size of you trans, 161 VA is not too bad.
At my power cost, 161 VA would be about $12 a month running 24/7.

 

[Nico Ras]

Dagwood, that transformer is physically quite massive and could put out huge magnetic field that could induce hum into everything close.

It may be worth considering mounting it outside of the amplifier in its own enclosure and you can build the power circuitry remotely from the amp.

 

[Dagwood]

Hi Nico

Thanks for that, due to the size my whole mounting / case ideas are out the window anyway......back to the old drawing board

 

[meanman1964]

planning to use a 2x30Vac transformer is the voltage OK for this amp?
If yes which one I shall use?I've two 2x30Vac/300VA transformers and one 2x30Vac/500VA transformer.

 

[evette]

Use the 2-300va transformers you won,t have any problems with that. Regards Evette

 

[meanman1964]

For Q12 the MPSW42 trannie is used any equivalent for this one ?

 

[evette]

I would check the spec on that trannies but I do believe anyone of the mje15030====series will work. Regards Evette

 

[meanman1964]

What about a normal MPSA42 what's the diffirence between this one and the one from ON semi?

 

[evette]

Dissapation. Evette

 

[OnAudio]

Thanks for the updates your feedback counts

 

[meanman1964]

I would check the spec on that trannies but I do believe anyone of the mje15030====series will work. Regards Evette

Joe,
Are you shure that's a TO220 case the MPSW42 is a TO92 case?

 

[evette]

Yes I know It,s a little trickey but it can be done,,or if you have a 2sc2705 transistor or any mje340 you know anything in this range of familys it will work..Evette

 

[meanman1964]

Thanks Joe(Evette)
A special reason for C8 being a bipolar?

 

[evette]

I just use a electro It really doesn,t matter in this case, Joe

 

[evette]

What outputs are you using? Joe

 

[meanman1964]

The same as you the MJH6284G

 

[Jay]

Question Regarding 1DIFFQC Harmonic Structure

Is it true that (with the basic/original components) the distortion spectrum is "odds are higher than evens"?