Influence of the delay amplifiers for listening characteristics

[PMA]

Well said, wahab. And the short circuit at the output is very likely, because the amp would be used on stage. One can never exclude such problem.

 

[wahab]

100% agree, Pavel..

I extensively played on stage, and from my experience,
output short circuit is not a likelyhood, but a certainity.

The only question is not if , but when will it happen..

One has to take a look at a PA pro amp, there s often more
components for protection circuitries than for the amplifying
purpose itself...

 

[jan.didden]

I repeat that a normal person can not operate long into the amplifier to short-circuit.

Mr Federmann, a suggestion:

You are no doubt a smart person but your language handicap prevents meaningful discussions here.
Why not spend one hour each week in an English language class?
You will gain the time spend many times back here (and maybe in your job).

best regards,

jd

 

[Federmann]

Oh no, but PA2 is only 2 x 55W amplifier. I assume that Sendy was meaning your 1kW amplifier (you have 20x more power than PA2), which is much more capable to yield high currents.

55W = 42Vp-p.

You showed very nice sinus, there is no current limit.

 

[PMA]

I have just tried more. At first, I have blown the PSU rail fuses. Then I have measured quite nice 13Apeak output current into 0R22, 1kHz sine. This is with 2 pairs of MJL21193/94.

 

[AndrewT]

55W = 42Vp-p.

no,
55W into 8r0 is equivalent to 29.7Vpk = 59.3Vpp.
55W into 4r0 is equivalent to 21Vpk = 42Vpp.

You must specify the power and the load for the information to be of any use.

 

[Federmann]

Then I have measured quite nice 13Apeak output current

Which occupies the current restrictions? Is not seen working?
How much is the rail voltage? How much power is the amplifier?

 

[PMA]

It is the PA2 amplifier. Rail voltage is 2 x 27V at idle, and it yields some 2 x 55W/4ohm. Clipping was shown somewhere (solid solid state amplifier thread).

 

[PMA]

Federmann, in case you would like to test with 0R22 load, please take into account that such load may change stability of the amplifier significantly.

 

[Federmann]

Federmann, in case you would like to test with 0R22 load, please take into account that such load may change stability of the amplifier significantly.

No worries.

27-5,83≈21V, Transistor power 21V*13A=273W



In your 55W amplifier it is 2 * MJL21193/94 ? (2 * 200W +2 * 200W?)

Current limit is more than 13A?

PMA: What is your transformer, please?
Performance on 1 channel 27V * 13A ≈ 350W
Performance on 2-Channel 700W?

 

[PMA]

Current limit is more than 13A?

Yes. It is determined by F4A fuses

 

[Federmann]

Yes. It is determined by F4A fuses

OK Pavel!
But the current no limitation on amplifier.

 

[PMA]

This amplifier is only for me and for my purposes. The current is limited only by PSU and fuses, and paralleled transistors have such SOA that they withstand short circuit (tested), with quite low supply voltage used.

If I built that amplifier for a customer, it would have a current protection circuits. Now it is just a research stage

 

[PMA]

Bohumil,

I have made a research test, just for you. 10Hz sine with gradually increasing amplitude, into 0R22 load. You can see the peak current when the power supply rail fuse has blown, it is about 20A peak

 

[Federmann]

When will the next amplifier, I also do interesting tests.

 

[Federmann]

400Hz sinewave, 80% output voltage with no load and with load 0,1 ohm, 5-10 sec duration.

To the impossible!
Current will be limited to less than 20A. Voltage on the load will be less than 2V. After a few ms off fuse!

Apply what I wrote.

 

[Sendy]

When will the next amplifier, I also do interesting tests.

Hi Federmann, what about testing your "overcurrent protection" ? Now you have a new piece of amplifier, what about measuring ?

 

[Federmann]

Measurements up to 200mΩ.

 

[Federmann]

Measurements up to 500mΩ.