I’m putting together a revised low distortion spot frequency generator for distortion measurements. I want a balanced output but haven’t decided on a transformer or active output yet.
The AP system 1 and Amber audio analyser used an output transformer I believe, with nfb taken from a special winding to cancel the transformers inherent distortion to <0.001%.
Does anyone know if this transformer can be readily bought as a spare or off-the-shelf part?
Cheers,
Glen
The AP system 1 and Amber audio analyser used an output transformer I believe, with nfb taken from a special winding to cancel the transformers inherent distortion to <0.001%.
Does anyone know if this transformer can be readily bought as a spare or off-the-shelf part?
Cheers,
Glen
G.Kleinschmidt said:
Don't know about AP, but Amber does not use such an animal. A Hammond transformer is used only to provide a floating output (employing a active stages). Hammond is still manufacturing such: http://www.hammondmfg.com/560.htm
Re: Re: Amber / AP1 output transformer?
Sorry, badly worded in haste - what you describe is what I mean. Thanks for the Hammond link. If you don't mind me nagging, which part # is used in the Amber and have you got an output amplifier schematic showing the implementation of that clever feedback scheme using that extra winding 🙂 ?
Cheers,
Glen
syn08 said:
Sorry, badly worded in haste - what you describe is what I mean. Thanks for the Hammond link. If you don't mind me nagging, which part # is used in the Amber and have you got an output amplifier schematic showing the implementation of that clever feedback scheme using that extra winding 🙂 ?
Cheers,
Glen
Re: Re: Re: Amber / AP1 output transformer?
Glen,
I have the Amber schematics. Unfortunately I'm on the road now, tonight I may scan and post the schematic.
But I don't recall any clever feedback loop involving the transformer. The output stage is simply a class A power amp having the input fed by the transformer (to provide ground isolation). The output is feeding a second identical power stage set to G=-1.
G.Kleinschmidt said:
Glen,
I have the Amber schematics. Unfortunately I'm on the road now, tonight I may scan and post the schematic.
But I don't recall any clever feedback loop involving the transformer. The output stage is simply a class A power amp having the input fed by the transformer (to provide ground isolation). The output is feeding a second identical power stage set to G=-1.
Re: Re: Re: Re: Amber / AP1 output transformer?
OK, thanks. That would be great.
Cheers,
Glen
syn08 said:
OK, thanks. That would be great.
Cheers,
Glen
Re: Re: Re: Re: Re: Amber / AP1 output transformer?
A memory flash brought up this reference for an AP US patent 4,614,914
http://www.freepatentsonline.com/4614914.html
It is certainly not the same in the Amber.
G.Kleinschmidt said:
A memory flash brought up this reference for an AP US patent 4,614,914
http://www.freepatentsonline.com/4614914.html
It is certainly not the same in the Amber.
Re: Re: Re: Re: Re: Re: Amber / AP1 output transformer?
OK, thanks - that rings a bell. I Though I wasn't imagining things 🙂
I was under the impression that the Amber unit was basically the same as the early AP.
Cheers,
Glen
syn08 said:
OK, thanks - that rings a bell. I Though I wasn't imagining things 🙂
I was under the impression that the Amber unit was basically the same as the early AP.
Cheers,
Glen
I would appreciate seeing the Amber schematics as well. I was able to repair my 5500 recently without them, but I think I need to recalibrate the internal frequency generator- It isn't outputting the entered frequencies accurately. Kind of a problem when you are trying to check RIAA curves.
Sorry to barge in on this thread, but I wanted to email Corvus corax to reply to a private message but unfortunately his private email doesn't work. I hope this reaches him. Please reply with a working email.
SYN08 - sorry to bug you this way....
You had mentioned in this thread that you had Amber schematics?
If you had them for the Amber 70... might you still have them..
this post is pretty darned old... but i have my fingers crossed.
You had mentioned in this thread that you had Amber schematics?
If you had them for the Amber 70... might you still have them..
this post is pretty darned old... but i have my fingers crossed.
Found a complete technical write-up covering everything I needed to know here (even a Landahl transformer part # and THD / freq. plots):
http://waltjung.org/PDFs/ADI_2002_Seminar_Ch6_Audio_Drivers_I.pdf
Page 29>
Feedback transformer coupled line drivers.
Cheers,
Glen
http://waltjung.org/PDFs/ADI_2002_Seminar_Ch6_Audio_Drivers_I.pdf
Page 29>
Feedback transformer coupled line drivers.
Cheers,
Glen
Glen, you can get the service manual for the AP-1 here - you need to log in.
http://ap.com/products/s1/resources
you might b e able to pick up some good ideas.
http://ap.com/products/s1/resources
you might b e able to pick up some good ideas.
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