MM1

Hallo allerseits.Ich lese schon einige zeit in diesem Forum mit und habe zwischenzeitlich eine AMI MM1 ,mit dem etwas missglückten 100 Watt Transistor Verstärker r3680a, uberholt.
An diesem Verstärker ist Oberhalb eines ausgangstrafo ein potentiometer verbaut ,bei mir waren nur mehr Kabeln vorhanden,welches in die AVC eingreift ,dieses ist in meinem Schaltplan nicht ausgeführt , Vielleicht weiß jemand den richtigen Wert.... Vielen dank im voraus Eric

Hello Eric,

We have spoken about the value of the AVC potentiometer and the lac of information in the manual.
If I still had a chassis I would of course have metered the control to give you an ohms value.

As you say maybe someone out there would be able to give us both the value of this pot for future reference.

Regards
Alan

Alan Hood
ami-man
UK

Hallo Alan


Also mit 100 kohm funktioniert die Avc Regelung problemlos. MfG Eric

Hello Eric,

I have found a very tidy MM-1 amplifier from stock which I have put onto Ebay for sale.

I have metered the control which is 1k ohm.
I hope this helps you.

Regards
Alan

Alan Hood
ami-man
UK

Okay thank u so i will try this .

Hello Alan

With 1k ohm it works better.

Do u know how many different Versions from the r3680a it gives,cause every 3680a i have seen ,looks different.
regards eric

Hello Eric,

I would guess at the reason that they look different is that on this and a number of early Rowe Ami amplifiers used tag stips to connect components to that there will have been slight variations on the way they were wired from each production opertative.
Even though they will have all been given the same instruction we all tend to do things our own way.

Regards
Alan

Alan Hood
ami-man

I ask cause i have here two pre amp ,both boards are looking original,some resistor(r30,r33,r32) are not the same as in the schematic,the Tantal elko in both are reverse the polarity mounted.


In my both Driver boards some resistors were never mounted.

regards eric

Hello

The R-3680 was the first solid state amplifier. In the original design, it was parallel to the TT - Motor connected and therefore at each record changing switched off and on. It turned out that it thereby came to many failures.

After a few months a factory recommendation came to connect the amplifier directly to the Power Supply. However, there were problems with the AVC thereby. It was necessary to make small changes in the circuit and to install the small pot. In later amplifiers, the change has already been performed at the factory, for the existing units an upgrade kit was delivered.

Best regards - charly49