Hello, I am working on a new project, This amp will work from 35 vdc to 60 vdc.
I got a transformer (used) that I found and I would love to use it. it is a 425vac 45v x2 after bridge rectifier I get 56 vdc, as you can see it is almost to the limit of the amp voltage.The capacitors are rated at 63 vdc so it is again in the limit of the voltage. I did tested it already and I kept an eye on the voltages and caps and it went ok the transformer it is a very good quality.I am worry that the voltages are almost on the limits of my project.But I was just checking some good design amps like Bryston B60 and they used caps of 50vdc on a circuit of 45 vdc. so the margin is just 5 vdc more.
My question is: Will this voltage be safe and reliable to run the amp?
I was thinking of getting a 500vac 35v x2 from Antek to get on the safe side, I know I will get less power since I can get around 150 watts RMS at 60 vdc on this amp project. The transformer that I have is an old one from a Portal Panache integrated amp, it is JEC (Jackson Engineering co.) Tibi Manufacturing 15-0121 rev.(custom made for them)
I got a transformer (used) that I found and I would love to use it. it is a 425vac 45v x2 after bridge rectifier I get 56 vdc, as you can see it is almost to the limit of the amp voltage.The capacitors are rated at 63 vdc so it is again in the limit of the voltage. I did tested it already and I kept an eye on the voltages and caps and it went ok the transformer it is a very good quality.I am worry that the voltages are almost on the limits of my project.But I was just checking some good design amps like Bryston B60 and they used caps of 50vdc on a circuit of 45 vdc. so the margin is just 5 vdc more.
My question is: Will this voltage be safe and reliable to run the amp?
I was thinking of getting a 500vac 35v x2 from Antek to get on the safe side, I know I will get less power since I can get around 150 watts RMS at 60 vdc on this amp project. The transformer that I have is an old one from a Portal Panache integrated amp, it is JEC (Jackson Engineering co.) Tibi Manufacturing 15-0121 rev.(custom made for them)
If I were you, I would get a transformer with a lower output voltage. It may have been fine when you tested it and yes, it is running below the maximum voltage for the amp but a small variation in mains voltage could make the output just that little bit higher and blow something up.
Even though the capacitors are rated for 63V, operating them at this level or just below could shorten their life span severely. Depending on the ratings of the other parts eg. the output transistors and input stage transistors, other capacitors, the amp may well run fine at this voltage. If all the other parts are adequately rated, you could try just upgrading the lower voltage capacitors.
Even though the capacitors are rated for 63V, operating them at this level or just below could shorten their life span severely. Depending on the ratings of the other parts eg. the output transistors and input stage transistors, other capacitors, the amp may well run fine at this voltage. If all the other parts are adequately rated, you could try just upgrading the lower voltage capacitors.
Although electrolytics caps can stand about 15% overvoltage,
it s better to use them at most at 80% of their voltage rating
as this keep allow DC main variation to stay within the range
of the caps garanteed voltage limits, so the option of a
2X35V AC transformer rather than 2X45V is to be seriously considered....
it s better to use them at most at 80% of their voltage rating
as this keep allow DC main variation to stay within the range
of the caps garanteed voltage limits, so the option of a
2X35V AC transformer rather than 2X45V is to be seriously considered....
63V electrolytics are designed and manufactured to work at 63V continuously.
They will accept some short term voltage overload, but I never plan to use any of that.
Depending on transformer regulation and mains supply tolerance, a 63Vdc capacitor can be connected to a maximum of about 40Vac to 42Vac transformer.
45Vac is virtually guaranteed to take the 63Vdc capacitors beyond rated maximum voltage if, or when, load is low and mains voltage is high.
They will accept some short term voltage overload, but I never plan to use any of that.
Depending on transformer regulation and mains supply tolerance, a 63Vdc capacitor can be connected to a maximum of about 40Vac to 42Vac transformer.
45Vac is virtually guaranteed to take the 63Vdc capacitors beyond rated maximum voltage if, or when, load is low and mains voltage is high.
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