Aaron amplifiers

[mad_z]

Hello @All,

Does anybody know anything about german amplifiers called aaron.

I happend to have one with broken power-on switch - which is not a problem, inside everything looks fine except for one resistor seems too small regarding wattage in PSU. The PSU itself looks strange as it uses 2x22 secondary from transformer connected to half wave rectifiers on board.


Anybody has any experience with them - after the PSU caps - large ones there is regulator and relay. Just after those large caps there are 2 resistors from +/- to ground but one is rated ~5W and the other looks like 1/4W - what is funny it does not seem to me that no service job has been done inside and the pcb looks like out of factory....:/

I am asking as I do not want have anyting burnt while using the unit when the power-on is exchanged.

Mine is Aaron no.6.

Any help apreciated.

Unfortunatelly I have no digicam to take a photo

Thanks!

[mad_z]

I have quickly drawed the part of psu - it is nasty as hell but shows how this is done. The red point are where the secondaries from transformer are connected.

[Franklin]

Dug up Aaron 3 schematics and hope they may be of benefit to you, although topology may have changed over the years.

[Franklin]

Here's the power supply schematic.

[mad_z]

Thanks a lot Franklin!!!

It is not identical but I can see some resemblances to pcb and parts used. I do not think the topology was much different as on pcb I can se empty places for more output transistors and jumpers to feed them with PSU as if it is ready to scale up for more power.

The output devices in mine are not mj1500x thouhg...

Anyway the scheme answers my worries - the resistors shall be rated at 5W as on the +/- nodes on the picture you have attached.

Great help!
Greetings!

[mad_z]

Yeap,


Having closer look at scheme I can see most of devices and ratings are matching 100%, except for mine have more uF in PSU and output devices are different. The drivers, caps, etc are the same.

[jacco vermeulen]

Should you still have questions about your nipple amplifier:

I know Thomas Hohne from the early days when he set up the Aaron line and started selling them, Neumann and Sovereign amplifiers.
The Aaron amplifiers are manufactured in Holland nowadays.
They still have a German Aaron internet site with a tech support line.

[mad_z]

Hi jacco,

Yes - I know the we-site.

I was about to write to them regarding my questions - now having the scheme I am sure the resistor vattage in psu is too small. The proper value I can check so I am going to exchange it for 5Watts. Rest of the parts look the sam for 2 channels and have not been touched by any service I think. The amplifier inside seems quite well manufactured and except for need to exchange few screws on the case I do not expect much trouble.

Dou you have any experience with these units?
What about sound? ....

I bought it second-hand for little money and in few days I will be back home and start it up and see myself

[Franklin]

Hello mad_z,

I'm glad the schematics could be of help to you and of course that you are able to solve the problem.

I cloned the Aaron 3 some 12 years ago. It is a class A/B amp but reveals more detail when quiescent current is raised to semi-class A. But if you attempt to do that, be caredfull! Turning the potmeter the wrong way may blow up the output transistors.

I will put a link on the website to download the schematics, wiring schematic and Eagle PCB-layout I made back then.

Hope you enjoy your Aaron 6.

[Tube_Dude]

Originally posted by mad_z



Anybody has any experience with them - after the PSU caps - large ones there is regulator and relay. Just after those large caps there are 2 resistors from +/- to ground but one is rated ~5W and the other looks like 1/4W - what is funny it does not seem to me that no service job has been done inside and the pcb looks like out of factory....:/

Hi mad_z

What is the value in Ohms of the resistors?

The 5W resistors in the schematic , are not between rails and ground as in your post.