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A&R A60 used as pre-amp

Radfordman

Radfordman

pfm Member
I fancy using an A60 as a pre-amp for some other power amp. Possibly Radford STA25 III, Quad 405-2, or Quad 303. I have all these.

Anyone have good suggestions for breaking into the A60 after the pre stage, but before power amp stage? Any good suggestions about extra sockets needed and extra de-coupling capacitor?
 
there should be a standard solution for this as A&R did it themselves to allow an A60 to be hooked up to a (I think) A60P slave power amp for bi-amping (ie the master A60 must have had a pre-amp out). As I recall it reqs no new sockets, as one of the existing inputs is changed to an output.

At least I think that's right. happy to stand corrected if not.
 
1000RPM said:
there should be a standard solution for this as A&R did it themselves to allow an A60 to be hooked up to a (I think) A60P slave power amp for bi-amping (ie the master A60 must have had a pre-amp out). As I recall it reqs no new sockets, as one of the existing inputs is changed to an output.

At least I think that's right. happy to stand corrected if not.
Click to expand...

Thanks, I know about that special A60 (think it may have an extra de-coupling capacitor as well), but I want to retain all the existing inputs.
 
Why not try just using the tape out signal? Saves adding extra sockets.
 
True that.
(I used the A60 for a while as a phono/pre but my amp has a volume pot.)
 
Pre amp final stage is the outputs from transistors Q8 & Q108, power amp inputs start with C22 & C122. The A60AP additional circuitry is detailed on the service manual (which can be viewed at the Retrohifi web site), however, it is not just a simple decoupling capacitor!
 
Analog addict said:
Pre amp final stage is the outputs from transistors Q8 & Q108, power amp inputs start with C22 & C122. The A60AP additional circuitry is detailed on the service manual (which can be viewed at the Retrohifi web site), however, it is not just a simple decoupling capacitor!
Click to expand...

Thanks for that, but what are the additional components for?
 
hello @Radfordman pls excuse me for reviving this thread, I would be doing some research in order to possibly implement an added preamp volume controlled signal output from the A60 for subwoofer duties..
I would still be using the A60 amp on the main speakers.
Wondering whether you have been able to implement the output discussed above?
or are maybe other gents able to chime in upon this topic?

According to schematic of my A60 (sn 14xxx), I would be thinking to implement something like what is indicated in the added blue circuit:

A60 preamp sub outhttps://www.flickr.com/photos/186638676@N05/

Any thoughts whether this could work?
TIA, cheers!
 
Hi there, I never got round to using the A60 as a pre only, but what you suggest seems reasonable.

In the past few years I've been using a TPA3116 amp mostly, as it's on all day and it's power consumption is minimal. Sounds pretty good too.
 
Thank you gents, it all appears to be working well as per previous indicated schematic!
I am attaching some pictures as a possible reference for other diyers, see the two added red circled 47uF caps (I found a spot for them in place of the tape output potentiometers which were not needed) and two wires soldered underneath, preout output is now connected to "tape din pins 1 (and 4)":

a&r a60 pre out 1

My subwoofer system is consisting of a further 12V opamp preamp to the main subwoofer analog volume level, then followed by a Behringer DCX2496 processor then by the amps, oops this is very likely a matter for another thread:

a&r a60 pre out 2https://www.flickr.com/photos/186638676@N05/

cheers!
 
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