Aaron Millenium 3, outputs tranzistors & quiescent current

[lemon]

Hi @all,

I have an Aaron Millenium 3, ver1.1 (20/06/2005) with problem on an output tranzistor - left channel - (unfortunately the signs of tranzistor has deleted from the factory).
I have find the following pcb schematic and according to this, the outputs tranzistor are pairs of MJ15003/15004. Is that true and happens to all Aaron versions?


If you have any other schematics about this final amplifier, I will appreciated!

If you can help me about how to set right the quiescent current, I will appreciated too (procedure and values).

Thanks

[AndrewT]

My Aaron is fitted with MJ15003/4 outputs.
Aaron literature tells lies about the low impedance capability of their amplifiers.

[lemon]

Do you know, what pcb revision has it? - there is a refference about this, under each pcb.

What you meaning, exactly with "Aaron literature tells lies about the low impedance capability of their amplifiers"?

[AndrewT]

They state the power output into 8r0, 4r0, 2r0 and 1r0 loads.

[lemon]

Aaron says:
Output power continuous sine wave per channel:
100W/8Ω 0.1% THD
160W/4Ω 0.1% THD

Output power pulsed per channel:
350W/2Ω 0.1% THD
410W/1Ω 0.1% THD

At the low impedance loads the "secret" is the term "pulsed"...they don't use the term "sine wave". Factory trick!

I have the equipment to measure all of this, but I haven't the appropriate "dummy load" for this power. Usually, I use "dummy load" until 60W/4-8 Ohm.

Yesterday, I found the problem to the right channel and fixed. I have some measures (thd+N, imd) between left & right channel (left has the new MJ15003/15004G, right has the factory tranzistor).
I will upload to my next message.

Cheers.

[lemon]

Happy New Year to all!

I come back with my Aaron No3. Millennium.

At listening test, everything is OK, but if you place your ear to the right speaker there is a "zzzz" from midrange & tweeter.

This appears and with thd+N metering, that there is a difference 0.023% vs 0.073%, with the noise threshold at the R channel more higher. I believe that the cause must be some transistor.

THD+N(%) Left Channel


THD+N(%) Right Channel


Also, my pcb differs from above schema (first message). I have per pcb 18 tranzistors vs 17 tranzistor that appears at the schema. I have enclosed two photos from my pcb.

I would be happy if someone gave me an extra pcb schema like mine board.

[lemon]

Originally Posted by AndrewT

My Aaron is fitted with MJ15003/4 outputs...

Is your amp, Aaron 3 or Aaron No3. Millennium?

[AndrewT]

Aaron No.3 Millennium

Here, you will find the right connection for the best speakers.

With output of

2 x 100 Watt at 8 Ohm

2 x 180 Watt at 4 Ohm

2 x 320 Watt at 2 Ohm

2 x 550 Watt at 1 Ohm

the No.3 Millennium is of course able to drive even impedance-critical speaker systems.

this is the lies. It's from
http://aaron.hifi.net/intl/no3.html

[tiefbassuebertr]

Originally Posted by lemon

Happy New Year to all!

I come back with my Aaron No3. Millennium.

At listening test, everything is OK, but if you place your ear to the right speaker there is a "zzzz" from midrange & tweeter.

This appears and with thd+N metering, that there is a difference 0.023% vs 0.073%, with the noise threshold at the R channel more higher. I believe that the cause must be some transistor.

most likely it is, that one of the transistors T1-4 has been noisy.
Check also the zeners Z1+Z2 so as the electrolytics C2+C3 (perhaps you add bypass caps, e. g. WIMA MKS, 1uF - 4,7uF).

What happens with the difference in noise, if you short the input to GND (short therefore C1 resp. R2) ?

About
http://new.audiogon.com/listings/433779
there are various pics.

[lemon]

Originally Posted by AndrewT

Aaron No.3 Millenniumthis is the lies. It's from
AARON ® No.3 Millennium * The High End Stereo Power Amplifier from Germany

- I agree with you, AndrewT. There is a "trick" at 2 & 1 Ohm from Aaron (pulse measuring).
Please, it is very important to me. You said that yours Aaron output transistor are pairs MJ15003/15004. Have you Aaron 3 or Aaron No3 Millennium?

Originally Posted by tiefbassuebertr

most likely it is, that one of the transistors T1-4 has been noisy.
Check also the zeners Z1+Z2 so as the electrolytics C2+C3 (perhaps you add bypass caps, e. g. WIMA MKS, 1uF - 4,7uF).

What happens with the difference in noise, if you short the input to GND (short therefore C1 resp. R2) ?

About
Aaron No.3 Millennium Stereo High End Amplifier | Solid | AudiogoN
there are various pics.

- Thanks for the respond to me "tiefbassuebertr". The problem has resolved. There was a "cold" soldering at the ground of left channel at the rca input. Now everything is OK.

To all members: I am looking for the kind of output transistor of Aaron No3. Millennium and if there is a pcb diagram, it is welcome!