Hello Gents,
I recently picked up an oldie which I'm planning ot refurbish as much as I can. I've done a PM-645-VXi a year ago which is now my daily driver. Did the basics like recapping, switch cleaning, trimpot replacement, resoldering etc...
With 665 I'd like go a step further and improve the signal-path if possible. Either with using much better components or even adding or changing the scheme a bit. I'm gonna need a bit a help to push me into the right direction.
I've added the predriver / powerstage part of the scheme to this thread and I do know more or less the actual signal-path but thats basically it🙂
Thx in advance for any advise here...
Willem
I recently picked up an oldie which I'm planning ot refurbish as much as I can. I've done a PM-645-VXi a year ago which is now my daily driver. Did the basics like recapping, switch cleaning, trimpot replacement, resoldering etc...
With 665 I'd like go a step further and improve the signal-path if possible. Either with using much better components or even adding or changing the scheme a bit. I'm gonna need a bit a help to push me into the right direction.
I've added the predriver / powerstage part of the scheme to this thread and I do know more or less the actual signal-path but thats basically it🙂
Thx in advance for any advise here...
Willem
In addition already a small question. Probably not a problem but you never know. The amp has 2 seperate transformers each driving one channel. The AC (transformed) output of one transformer is 96.4 volt while the other has 95.8 volt. I reckon thats not a problem....🙂
thx
w.
thx
w.
Ok cool......Here is the scheme of one of the transformer. Would it make sense to add 2 snubber circuits to both transformers?...I've read Quasimodo's post and found this article about it. Obviously a discussion much talked about in the past with various opinions as usual🙂....I don't have scope (maybe should get one.....
One tramsformer of the 665-VXi (C3 and C5 100nF already there)
Snubber circuit (with probe)
One tramsformer of the 665-VXi (C3 and C5 100nF already there)
Snubber circuit (with probe)
Why not use a single, 3 element (C-R-C) snubber for each transformer secondary as Mark's app note shows?
And yes, if you're going to do things that would likely alter an amp's characteristics (such as stability, for example), it would be dangerous to not have a scope ...
And yes, if you're going to do things that would likely alter an amp's characteristics (such as stability, for example), it would be dangerous to not have a scope ...
Ok clear. Looking for a simple scope now. Another thing which comes to my mind is this. Each transformer has 2 secondary centre-tapped windings. I'm only using the one with the higher voltage. Do I have to shortcut the other winding of each transformer making sure to not interfere in some way?
reg
willem
reg
willem
Euhm....my bad and a stupid suggestion of me as well. Apologies. When I would short the secondary, the primary effectively is shorted as well causing a BOOM.
reg
willem
reg
willem
