Fantastic Info!
@alv
Hi ALV
Thanks for all of this great info. You've gone to a lot of trouble here. Appreciated.
I'm a few weeks away from getting my amp pulled apart again, but I will definitely report back on how I go with this IDLE BIAS process.
Also, very interesting info about the potentially suspect narrow grey capacitors...
Great Post!
@alv
Hi ALV
Thanks for all of this great info. You've gone to a lot of trouble here. Appreciated.
I'm a few weeks away from getting my amp pulled apart again, but I will definitely report back on how I go with this IDLE BIAS process.
Also, very interesting info about the potentially suspect narrow grey capacitors...
Great Post!
120V to 240V Power Transformer Upgrade Specifications?
@Alv
Hi Alv!
Its been a fair while since your post below. I trust you are well.
Your advice on this thread has been an invaluable reference for me. Thank you.
As the title of this post suggests, I'm considering changing my US-centric AVANCE Z501 from 120V to 240V operation, to fall in line with local mains supply in AU/NZ.
I'd like to source a suitable PT replacement - unluckily, my original US PT model 2553 is the model WITHOUT the spare windings for 240V operation - but the Z501 schematic does not state voltages on the windings.
Would you happen to know the transformer specifications for the 240V AVANCE Z501 PT?
Any info you can share would be much appreciated.
@Alv
Hi Alv!
Its been a fair while since your post below. I trust you are well.
Your advice on this thread has been an invaluable reference for me. Thank you.
As the title of this post suggests, I'm considering changing my US-centric AVANCE Z501 from 120V to 240V operation, to fall in line with local mains supply in AU/NZ.
I'd like to source a suitable PT replacement - unluckily, my original US PT model 2553 is the model WITHOUT the spare windings for 240V operation - but the Z501 schematic does not state voltages on the windings.
Would you happen to know the transformer specifications for the 240V AVANCE Z501 PT?
Any info you can share would be much appreciated.
Hello again,
Due to the various specific tappings on the transformers secondary winding's (see circuit diagram), it wouldn't be a simple job to find a suitable 240vac primary replacement transformer. You would probably need to have one specially made to fulfill the same (various) functions. It's a fairly complex arrangement with the ability to change from class AB to A via a switch/relay combination.
You could try to find another 240vac tranny from another 240v Z501 model? there may be an old non working one out there somewhere that could be salvaged for parts - poss place an advert for one? The other possibility and the more likely of quick success is to supply the amp from a step down transformer (which I assume you do now). The larger rated in volt/amp terms that the step down transformer is the better otherwise the mains impedance of the supply could suffer (increase) using a small underrated step down tranny and your Z501's full potential wouldn't be realized. A 1000va one would be ideal though you could get away with less current capability. Mains impedance (resistance) is important especially with a power amp as it draws heavy current from the mains each time it's required to 'top up' the amps power supply reservoir capacitors on demand.
By the way do you have the Z501 owners manual and the workshop manual; they could be useful to you.
Regards, Alv.
Due to the various specific tappings on the transformers secondary winding's (see circuit diagram), it wouldn't be a simple job to find a suitable 240vac primary replacement transformer. You would probably need to have one specially made to fulfill the same (various) functions. It's a fairly complex arrangement with the ability to change from class AB to A via a switch/relay combination.
You could try to find another 240vac tranny from another 240v Z501 model? there may be an old non working one out there somewhere that could be salvaged for parts - poss place an advert for one? The other possibility and the more likely of quick success is to supply the amp from a step down transformer (which I assume you do now). The larger rated in volt/amp terms that the step down transformer is the better otherwise the mains impedance of the supply could suffer (increase) using a small underrated step down tranny and your Z501's full potential wouldn't be realized. A 1000va one would be ideal though you could get away with less current capability. Mains impedance (resistance) is important especially with a power amp as it draws heavy current from the mains each time it's required to 'top up' the amps power supply reservoir capacitors on demand.
By the way do you have the Z501 owners manual and the workshop manual; they could be useful to you.
Regards, Alv.
@Alv
Hi Alv!
Thanks for these thoughts.
Yes, I already run a step-up transformer, but keen to tidy things up.
I have kept my eyes open for a parts donor amp for some time now, but the few of these rare amps that come up for sale are typically 120V also.
I agree that my last resort is to price-up a new 240V power transformer, which is why I am trying to confirm exact PT specifications.
Yes, I have the original owners manual, which has a very clear schematic of the amp at the rear. Exact PT windings values do not appear to be stated.
Hi Alv!
Thanks for these thoughts.
Yes, I already run a step-up transformer, but keen to tidy things up.
I have kept my eyes open for a parts donor amp for some time now, but the few of these rare amps that come up for sale are typically 120V also.
I agree that my last resort is to price-up a new 240V power transformer, which is why I am trying to confirm exact PT specifications.
Yes, I have the original owners manual, which has a very clear schematic of the amp at the rear. Exact PT windings values do not appear to be stated.
Attachments
Hello SONDEKNZ,
Due to the fact that you live in New Zealand with a (230v/50Hz) mains supply and you are powering your Z501 from a 120v/(60Hz)? power transformer I thought I would let you know (although you may not like to hear it) that supplying a 60Hz transformer from a 50Hz supply could over stress the transformer (overheat) in your case that would be in class A mode at fairly high power levels.
Running a 50Hz transformer on 60Hz would be no problem at all though, 50Hz transformers are typically 20% larger than their 60Hz equivalents. So it probably would be a good idea if you could get your hands on a 50Hz rated tranny?
By the way if you would like a copy of the Workshop manual (not the Owners manual) I could attach page copies for you but you would probably need to forward your e-mail address to me.
Regards.
Due to the fact that you live in New Zealand with a (230v/50Hz) mains supply and you are powering your Z501 from a 120v/(60Hz)? power transformer I thought I would let you know (although you may not like to hear it) that supplying a 60Hz transformer from a 50Hz supply could over stress the transformer (overheat) in your case that would be in class A mode at fairly high power levels.
Running a 50Hz transformer on 60Hz would be no problem at all though, 50Hz transformers are typically 20% larger than their 60Hz equivalents. So it probably would be a good idea if you could get your hands on a 50Hz rated tranny?
By the way if you would like a copy of the Workshop manual (not the Owners manual) I could attach page copies for you but you would probably need to forward your e-mail address to me.
Regards.
I finally scanned the A501 / Z501 build instructions that are in English.
I built mine over 25 years ago, so there may be a few mistakes or misprints. I seem to remember it was nothing that presented a problem.
A501 Z501 English Build Manual.pdf - Google Drive
enjoy Z
I built mine over 25 years ago, so there may be a few mistakes or misprints. I seem to remember it was nothing that presented a problem.
A501 Z501 English Build Manual.pdf - Google Drive
enjoy Z
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