I really hope I am in a right thread. Hi Guys. I need help. 1/2 way building a spare Peter Daneils Premium kit. As been suggest the transfo secondary is 23-0 x 2 for this kit. I would like to push the output W higher, say to 50W above. What Secondary value V should I go for on the transfo? I have a spare Cyrus toridal at 29v x2. Can I use it? Tq guys!
What is the transformer's rated input voltage for that 29Vac output?
What is the transformer's rated regulation?
Then you can predict the maximum voltage, after the rectifier, when your mains is at maximum supply voltage.
We can't invent those numbers for you.
What is the transformer's rated regulation?
Then you can predict the maximum voltage, after the rectifier, when your mains is at maximum supply voltage.
We can't invent those numbers for you.
Hi Andrew,
It was removed from Cyrus III. Input is
230- 0
Secondary is:
29v - 0v - 29v
7v - 0v
Looks like less hope? I see nothing written for the regulation. Supplied by Toroid Intl.Etd.
If this can't work, I have to custom 1. 🙁
It was removed from Cyrus III. Input is
230- 0
Secondary is:
29v - 0v - 29v
7v - 0v
Looks like less hope? I see nothing written for the regulation. Supplied by Toroid Intl.Etd.
If this can't work, I have to custom 1. 🙁
you have a 230:29-0-29Vac.
You still need information for maximum mains supply voltage and for transformer regulation.
Maximum output voltage is :
maximum input voltage / rated input voltage * rated output voltage * {transformer regulation plus 1}
From there the peak voltage into the rectifier is sqrt(2) * maximum output voltage.
Maximum output voltage from the bridge rectifier is ~ peak voltage minus ~1V
Find the missing information.
Calculate the numbers.
Then from the datasheet see what the maximum supply voltage that is allowed.
You still need information for maximum mains supply voltage and for transformer regulation.
Maximum output voltage is :
maximum input voltage / rated input voltage * rated output voltage * {transformer regulation plus 1}
From there the peak voltage into the rectifier is sqrt(2) * maximum output voltage.
Maximum output voltage from the bridge rectifier is ~ peak voltage minus ~1V
Find the missing information.
Calculate the numbers.
Then from the datasheet see what the maximum supply voltage that is allowed.
That does not help.
Contact your Mains electricity supplier and ask them what the range of voltage for your domestic supply.
It is likely to be around 210Vac to 250Vac.
You need to contact your transformer manufacturer, or study the datasheet, for the transformer model you have and ask what is the transformer regulation.
Once you have these figures you calculate the maximum voltage as shown earlier.
If it exceeds the signal present maximum for the chipamp then you run the risk of blowing up your chip.
Hi Andrew. Our domestic is 240v. Okie I try to search for the transfo spec and will catch up with you.
Your domestic supply varies.
of voltage depends on the supplier.
You need to ask them.
The minimum range is usually +-6%, some can be +-10%, It's even possible that your range could exceed +-10%.
ASK !
Hi Andrew,
In fact I look for the tranny guy and custom according to original GainCard 170va x 2 and complete the amp couple days ago. Without worrying too much I do enjoy the Gainclone. Good news is it sound really special but bad thing is I prefer it to my Naim.
I borrowed a meter and plug into the outlet. In fact yes, the voltage varies. lowest show 212v and highest (at night) 230v.
In fact I look for the tranny guy and custom according to original GainCard 170va x 2 and complete the amp couple days ago. Without worrying too much I do enjoy the Gainclone. Good news is it sound really special but bad thing is I prefer it to my Naim.
I borrowed a meter and plug into the outlet. In fact yes, the voltage varies. lowest show 212v and highest (at night) 230v.
Hi Andrew,
Having it switch on from yesterday until now, yah this kit is really stable. Firstly no humming, and no hiss at all as I volume to 1 o'clock and above. Built fast and screw everything on a board. I am happy.
Now I look at the meter and surprised me that it reads 238, and now 235.
Btw, I was wondering, if I make another tranny same and mono this amp would is be better? and any possibility of hum? Or I making a new one with a bigger size helps? Ie 4A or 5A tranny?
Many thanks!
Having it switch on from yesterday until now, yah this kit is really stable. Firstly no humming, and no hiss at all as I volume to 1 o'clock and above. Built fast and screw everything on a board. I am happy.
Now I look at the meter and surprised me that it reads 238, and now 235.
Btw, I was wondering, if I make another tranny same and mono this amp would is be better? and any possibility of hum? Or I making a new one with a bigger size helps? Ie 4A or 5A tranny?
Many thanks!
That's just under +-6%, based on a nominal 225Vac.
Not bad, it could be worse and the probably is worse, at times you have not measured the voltage.
Not bad, it could be worse and the probably is worse, at times you have not measured the voltage.
A bigger transformer usually has a lower regulation. That lower regulation is often a bigger benefit that separate smaller transformers in a stereo amplifier.
4A 25-0-25Vac is 200VA. A toroid could be around 6% to 7% regulation. An EI could be approaching double that.
That 200VA can support a total maximum output power of 100W to 200W. That is OK for a Cyrus which is around 30W to 50W per channel.
29-0-29Vac is too high for any of the National chipamps.
4A 25-0-25Vac is 200VA. A toroid could be around 6% to 7% regulation. An EI could be approaching double that.
That 200VA can support a total maximum output power of 100W to 200W. That is OK for a Cyrus which is around 30W to 50W per channel.
29-0-29Vac is too high for any of the National chipamps.
Hi Andrew,
A couple questions. Just now the meter reads at 225v after 3 hours playing, and I measure the dc but speaker plug off. Both sides shows 30.5 - 30.6 dc. As the tranny made secondary 23.5, roughly how many watt is this amp produce? I am using a pair of 11 ohm speaker.
With Dc 30.5~6, will the chip runs okie?
Thanks!
Alfred.
A couple questions. Just now the meter reads at 225v after 3 hours playing, and I measure the dc but speaker plug off. Both sides shows 30.5 - 30.6 dc. As the tranny made secondary 23.5, roughly how many watt is this amp produce? I am using a pair of 11 ohm speaker.
With Dc 30.5~6, will the chip runs okie?
Thanks!
Alfred.
Now I know why we need a bigger tranny. Will keep the 29-029Vac to build something else.
the maximum output power is given by multiplying the maximum output voltage by the maximum output current into the resistive dummy load.
National make it easier for you. Read the datasheet.
Do you really have 11ohm speaker/s?
National make it easier for you. Read the datasheet.
Do you really have 11ohm speaker/s?
After listening these days, I realized it sounds good when current reads 233v. Better focus in vocal and overall sound. Does it really affect or I am I jist to sensitive when week end comes? 😉
