Hi Jeff,
that transformer should easily support 300W into 6ohms.
If you require adequate performance into a 4ohm load then add a bit more smoothing to help hold up the supply rail voltage.
that transformer should easily support 300W into 6ohms.
If you require adequate performance into a 4ohm load then add a bit more smoothing to help hold up the supply rail voltage.
I'm sorry if I missed something in going through these posts, but even if the power supply can support 300 watts, the modules cant, right? I mean, I wasn't under the impression that these modules would dissipate that much power. I'm sure if you added a few more output devices it could.
By the way, I'm finding right now that with two 600+va transformers, which should equal a bit more than 1.2kva, and with the limited number of capacitors in the power supply right now, the amp sounds limited in the dynamics. It's clipping behavior is great if you aren't playing in the clipped zone, but I'm finding it can clip quite easily. Mind you thats at volumes over 100 db's. I don't want the amp to play that loud necessarily, but I would like clean headroom out to that point. I'm thinking adding the third transformer, a soft start circuit, and more capacitors will fix these things. In measuring the voltage, I'm finding that its dropping more than expected at those peaks, compared to what I saw on my simulations. I'm also finding that the Inductors are heating up more than I thought, so I think I will have to hook the second coil back in, which will increase current to 16 amps, but lower inductance to 8mh instead of 11. The difference is really pretty small in performance, so I can't complain. This does reinforce more and more the benefit of having indipendant supplies for each amp, I just don't have space for 3 transformers, 6 inductors, and 24+ capacitors rated at 22,000uf's. Maybe some day, but thats a lot.
By the way, I'm finding right now that with two 600+va transformers, which should equal a bit more than 1.2kva, and with the limited number of capacitors in the power supply right now, the amp sounds limited in the dynamics. It's clipping behavior is great if you aren't playing in the clipped zone, but I'm finding it can clip quite easily. Mind you thats at volumes over 100 db's. I don't want the amp to play that loud necessarily, but I would like clean headroom out to that point. I'm thinking adding the third transformer, a soft start circuit, and more capacitors will fix these things. In measuring the voltage, I'm finding that its dropping more than expected at those peaks, compared to what I saw on my simulations. I'm also finding that the Inductors are heating up more than I thought, so I think I will have to hook the second coil back in, which will increase current to 16 amps, but lower inductance to 8mh instead of 11. The difference is really pretty small in performance, so I can't complain. This does reinforce more and more the benefit of having indipendant supplies for each amp, I just don't have space for 3 transformers, 6 inductors, and 24+ capacitors rated at 22,000uf's. Maybe some day, but thats a lot.
4 ohm
Hii AndrewT
For the best perfomance into 4ohm load,
how much transformer size i must use it ?
Is this for one or two channel ?
If i use 500 va 2 x 45v, it is the best for 1 or 2 channel ?
with 60000uf / 63v each psu, which the best ( below )
A. 1 trans - 1 PSU - 2 Channel
B. 1 trans - 2 PSU - 2 Channel
C. 2 trans - 2 psu - 2 Channel
AndrewT said:
Hii AndrewT
For the best perfomance into 4ohm load,
how much transformer size i must use it ?
Is this for one or two channel ?
If i use 500 va 2 x 45v, it is the best for 1 or 2 channel ?
with 60000uf / 63v each psu, which the best ( below )
A. 1 trans - 1 PSU - 2 Channel
B. 1 trans - 2 PSU - 2 Channel
C. 2 trans - 2 psu - 2 Channel
Member
Joined 2002
AndrewT said:
The more Va the better, That transformer you posted, it being potted and shielded will be really nice to have, over here those are a pretty penny. If you can afford it, then do it.
jeffery: " ... For the best perfomance into 4ohm load, how much transformer size i must use it ? Is this for one or two channel ? ..."
jleaman: " ...The more Va the better, That transformer you posted, it being potted and shielded will be really nice to have ..."
Simply increasing transformer sizes is not really necessary in the case of these power MOSFET amps. Generally, output power can increase linearily while thermal power radiation may only increase as a factor of thermal efficiency.
In the case of AndrewT's suggestions for using a 300 watt (300 VA) transformer as being adequate for two 150 Watt MOSFET channels into 6 Ohms each ... a very modest increase in the heat sink may be all that is required for the same setup to drive into 4 Ohms.
A lot of this is trial and error rather than extrapolation from rules or formula. My dual channel NX150 MOSFET amp is powered from a Crown 300VA torrid transformer with a resulting DC rail voltage of 67 VDC ~ equal to 200+ Watts into 4 Ohms, each channel ... but unless I run it for several hours, the heat sinks recommended by AussieAmplifiers.com never seem to get much above room temperature = and the transformer stays cool as well without any fan or special ventilation. Thermal and power considration seem to have more to do with listening levels in the cases of MOSFET amps = louder requires more power from the power supply ...( http://3dotaudio.com/ampics.html now driving http://www.magnepan.com/model_MMG = 4 Ohms)
jleaman: " ...The more Va the better, That transformer you posted, it being potted and shielded will be really nice to have ..."
Simply increasing transformer sizes is not really necessary in the case of these power MOSFET amps. Generally, output power can increase linearily while thermal power radiation may only increase as a factor of thermal efficiency.
In the case of AndrewT's suggestions for using a 300 watt (300 VA) transformer as being adequate for two 150 Watt MOSFET channels into 6 Ohms each ... a very modest increase in the heat sink may be all that is required for the same setup to drive into 4 Ohms.
A lot of this is trial and error rather than extrapolation from rules or formula. My dual channel NX150 MOSFET amp is powered from a Crown 300VA torrid transformer with a resulting DC rail voltage of 67 VDC ~ equal to 200+ Watts into 4 Ohms, each channel ... but unless I run it for several hours, the heat sinks recommended by AussieAmplifiers.com never seem to get much above room temperature = and the transformer stays cool as well without any fan or special ventilation. Thermal and power considration seem to have more to do with listening levels in the cases of MOSFET amps = louder requires more power from the power supply ...( http://3dotaudio.com/ampics.html now driving http://www.magnepan.com/model_MMG = 4 Ohms)
Member
Joined 2002
Member
Joined 2002
Re: 4 ohm
you really must get that calculator out or measure the DC output voltage of your proposal.
The Maximum Vac for 60Vdc capacitors is about 40Vac.
(assumming 7% regulation and 6% tolerance on mains supply.
45Vac requires 75Vdc or 80Vdc capacitors.
500VA divided by 1 to 2 gives the maximum total amplifier output.
I find using /1.5 works very well. This gives about 300W total.
Using your transformer voltage of 45Vac you will get about that maximum power into a 6r0 load. If you use an 8r0 load the maximum power will be about 200W (or a little less) and you could probably run two channels off this transformer into 8ohm speakers. But if you reduce the load to 4r then the power should go upto about 400W and this transformer is a little small. That is why I said try increasing the supply capacitance to help hold up the supply voltage on heavy loading.
I would normally recommend +-20mF for a single channel into 8ohm. And increase this to +-40mF into 4ohm. But I am suggesting that this should be increased to maybe +-60mF to make this transformer work adequately into a 4ohm load.
120mF of 80Vdc smoothing caps are going to cost a lot. But that is the price of good bass and high power.
Hi Jeff,jeffry_widjaja said:
you really must get that calculator out or measure the DC output voltage of your proposal.
The Maximum Vac for 60Vdc capacitors is about 40Vac.
(assumming 7% regulation and 6% tolerance on mains supply.
45Vac requires 75Vdc or 80Vdc capacitors.
500VA divided by 1 to 2 gives the maximum total amplifier output.
I find using /1.5 works very well. This gives about 300W total.
Using your transformer voltage of 45Vac you will get about that maximum power into a 6r0 load. If you use an 8r0 load the maximum power will be about 200W (or a little less) and you could probably run two channels off this transformer into 8ohm speakers. But if you reduce the load to 4r then the power should go upto about 400W and this transformer is a little small. That is why I said try increasing the supply capacitance to help hold up the supply voltage on heavy loading.
I would normally recommend +-20mF for a single channel into 8ohm. And increase this to +-40mF into 4ohm. But I am suggesting that this should be increased to maybe +-60mF to make this transformer work adequately into a 4ohm load.
120mF of 80Vdc smoothing caps are going to cost a lot. But that is the price of good bass and high power.
no,FastEddy said:
Jeff's 45Vac will not give 150W+150W into 4r0, unless it is very badly assembled with the wrong choice of components.
It should give at least 150W +150W into 8r0 and with careful choice of build, approach 200W into 8r0.
JLEAMAN !, im happy to see you again
I think your GF go back to Canada so
you left us for a while 😀
My last physics lesson was in high school at 1993
and my electronic lesson was 1990 at junior high
This realy ... realy ... craziest project i did
Thats why i buy AussieAmp, so i can plugs the cable
and heres come the sound but not that easy 😀
For AndrewT, Thanks for remind me
At the first time, i got little shocked when i read your post
oh no i was make a big mistake to buy 20pcs 10000uf 63v
but after i look again some information at aussieamp website
http://www.aussieamplifiers.com/index3.htm
Recommended Supply Specifications
+/- 56vdc voltage rails
146 Watts RMS into 8 Ohms
230 Watts RMS into 4 Ohms
1 x 300VA toroidal transformer with 2 x 40 Vac secondary windings. +-56 Volt Rails (Idle)
Minimum 2 x 10,000uf 80v filter caps required
Or PSU-Two Power Supply Unit
1 x MDA3504 Bridge Rectifier
For Dual Channel Stereo
400-500VA Toroidal Transformer
+/- 63 vdc voltage rails
185 Watts RMS into 8 Ohms
275 Watts RMS into 4 Ohms
1 x 400VA toroidal transformer with 2 x 45 Vac secondary windings. +-63 Volt Rails (Idle)
Minimum 2 x 10,000uf 80v filter caps required
Or PSU-Two Power Supply Unit
1 x MDA3504 Bridge Rectifier
For Dual Channel Stereo
500-625VA Toroidal Transformer
Maybe FATHER make something magic with them
im glad i use those psu 3, as i remember FastEddy use
PSU 3 too, what capacitor and transformer you use FE?
I think your GF go back to Canada so
you left us for a while 😀
My last physics lesson was in high school at 1993
and my electronic lesson was 1990 at junior high
This realy ... realy ... craziest project i did
Thats why i buy AussieAmp, so i can plugs the cable
and heres come the sound but not that easy 😀
For AndrewT, Thanks for remind me
At the first time, i got little shocked when i read your post
oh no i was make a big mistake to buy 20pcs 10000uf 63v
but after i look again some information at aussieamp website
http://www.aussieamplifiers.com/index3.htm
Recommended Supply Specifications
+/- 56vdc voltage rails
146 Watts RMS into 8 Ohms
230 Watts RMS into 4 Ohms
1 x 300VA toroidal transformer with 2 x 40 Vac secondary windings. +-56 Volt Rails (Idle)
Minimum 2 x 10,000uf 80v filter caps required
Or PSU-Two Power Supply Unit
1 x MDA3504 Bridge Rectifier
For Dual Channel Stereo
400-500VA Toroidal Transformer
+/- 63 vdc voltage rails
185 Watts RMS into 8 Ohms
275 Watts RMS into 4 Ohms
1 x 400VA toroidal transformer with 2 x 45 Vac secondary windings. +-63 Volt Rails (Idle)
Minimum 2 x 10,000uf 80v filter caps required
Or PSU-Two Power Supply Unit
1 x MDA3504 Bridge Rectifier
For Dual Channel Stereo
500-625VA Toroidal Transformer
Maybe FATHER make something magic with them
im glad i use those psu 3, as i remember FastEddy use
PSU 3 too, what capacitor and transformer you use FE?
note the recommendation to use 80Vdc capacitors!!!!!
A 45Vac transformer with regulation of 5% will give 47.2Vac when opencircuit.
The rectified voltage will be about 66.8-0.7=~=66Vdc when off load.
Now add mains supply tolerance. +6% gives 70Vdc. This is way over what a 63Vdc capacitor can reliably withstand.
I repeat, the maximum voltage for a 63Vdc cap is about 40Vac when regulation is 7% and supply tolerance is 6%.
Your 20pieces will give you +-50mF per channel, probably enough for a 500VA 40Vac transformer to give good bass into 4ohms.
BTW,
my Leach clone gives 311W into 4ohms from 40Vac.
230W is nothing special, see what happens when FETs are used. Don't always believe the protagonists that claim Low Rds solves everything.
" ... note the recommendation to use 80Vdc capacitors!!!!! ..."
I used 100 volt caps on my 67 VDC rails ... and still worry about safety and long term reliability. It never pays to push the limits on capacitor voltage ratings ... a 20% safety factor is not enough IMOP ... zzzzzztttt ... smoke, stink ...
FYI: two channels at 150 watts each is 300 Watts = almost 1/2 horse power and a whole lot of lightning in your hand. !
I used 100 volt caps on my 67 VDC rails ... and still worry about safety and long term reliability. It never pays to push the limits on capacitor voltage ratings ... a 20% safety factor is not enough IMOP ... zzzzzztttt ... smoke, stink ...
FYI: two channels at 150 watts each is 300 Watts = almost 1/2 horse power and a whole lot of lightning in your hand. !
I wanted to give a slight update on my current situation. I wanted to make sure all my capacitors were discharged before packing for my move, and I found a few things. First, one of the transformers wasn't hooked up. Kinda scarey to think I had flying leads, but thankfully, the side with the loose leads was the AC in, and thats why I was seeing such extreme voltage drops as load increased. I have not yet heard my amp with 1.2kva of transformer, and I still have only 44mf of capacitance on the load end. I have 88mf if you include the 44mf before the inductors, but I gathered from AndrewT that these would be of little consequence to feeding the amps changing load. I'm really not sure how much of a difference the inductors have for energy storage, so I don't know how to compare my energy storage to that of a normal capacitor supply. I know it has much lower ripple, but not how it affects voltage drop for instance, or even current.
Anyway, once I move I will add another 22mf's per rail, 44mf's total, to the amp chassis itself, and another 22mf's, or 44mf's total to the power supply chassis. This will change the C2 part of the (C1L1C2)CLC power supply from 22mf's per rail to 66mf's per rail, or 132mf's total after the inductor. So AndrewT, if this isn't enough, then I give up, cuz that is all the room I have. I also will add the RC networks when I have the parts, and Modifying the C1 of the CLC to handle the ripple currents better.
I also promised some input on my experience with different tweak parts. I obviously have been unable to test anything as I'm moving. However, during my move I found some PP Wima 1uf caps, some ClarityCap SA caps in 1uf, along with a .33uf, and a 1.8uf value. The .33uf will raise the bass cutoff to I think around 15hz or so, and the 1.8 will lower it to 2-5hz I believe. I don't actually know how to calculate it, but based on the numbers I was given for .47 and 1uf, thats my best guess. Those will be my first tries, and given the good reviews of the SA series of caps, I expect a good difference between that and the stock cap. We shall see how it compares with the Wima, which I find to be a good, but not great cap. I will let you know, I thought you might like an update on my power supply situation, since it might have made some a bit more concerned about the dynamic performance of the amps than is necessary.
Anyway, once I move I will add another 22mf's per rail, 44mf's total, to the amp chassis itself, and another 22mf's, or 44mf's total to the power supply chassis. This will change the C2 part of the (C1L1C2)CLC power supply from 22mf's per rail to 66mf's per rail, or 132mf's total after the inductor. So AndrewT, if this isn't enough, then I give up, cuz that is all the room I have. I also will add the RC networks when I have the parts, and Modifying the C1 of the CLC to handle the ripple currents better.
I also promised some input on my experience with different tweak parts. I obviously have been unable to test anything as I'm moving. However, during my move I found some PP Wima 1uf caps, some ClarityCap SA caps in 1uf, along with a .33uf, and a 1.8uf value. The .33uf will raise the bass cutoff to I think around 15hz or so, and the 1.8 will lower it to 2-5hz I believe. I don't actually know how to calculate it, but based on the numbers I was given for .47 and 1uf, thats my best guess. Those will be my first tries, and given the good reviews of the SA series of caps, I expect a good difference between that and the stock cap. We shall see how it compares with the Wima, which I find to be a good, but not great cap. I will let you know, I thought you might like an update on my power supply situation, since it might have made some a bit more concerned about the dynamic performance of the amps than is necessary.
hello everyone
Dear Pak jefry kalau anda jadi ambil toroidal sari aphex junior seperti yang anda tunjukkan di halaman sebelumnya saya mau dong ikutan pesen 2 unit. thanx ya.
SMS saya di 08882850215
Dear Pak jefry kalau anda jadi ambil toroidal sari aphex junior seperti yang anda tunjukkan di halaman sebelumnya saya mau dong ikutan pesen 2 unit. thanx ya.
SMS saya di 08882850215
PS This is an english forum
Dear Rembulan
You can contact the seller, this is very easy
For the apex transformer (Genesis) you must email
steve.apexjr@prodigy.net
steve is a kind person, for payment you can pay by
paypal or you can transfer by bca ( Rp. 50.000,- )
For the nuvotem transformer you can contact
htpp://www.rssingapore.com/
( this for encapsulated transformer / with casing )
more expensive but 😎
In Indonesia there is transformer from where Hartono
living right now, you can use it very cheapest transformer.
but if you want to use 400 va, 2 x 45 v for the amp,
1. you can change to 500 va or 625 va
2. Use 2 pcs 400 va, 2 x 45 v or 500 va
China transformer is very cheap and if you use bigger or
double must be enough to power you amplifier
If i dont use it for drive Totem Forest i will choose it
my transformer are arrived, so you cant join order
with me, maybe next time. 😀
Dear Rembulan
You can contact the seller, this is very easy
For the apex transformer (Genesis) you must email
steve.apexjr@prodigy.net
steve is a kind person, for payment you can pay by
paypal or you can transfer by bca ( Rp. 50.000,- )
For the nuvotem transformer you can contact
htpp://www.rssingapore.com/
( this for encapsulated transformer / with casing )
more expensive but 😎
In Indonesia there is transformer from where Hartono
living right now, you can use it very cheapest transformer.
but if you want to use 400 va, 2 x 45 v for the amp,
1. you can change to 500 va or 625 va
2. Use 2 pcs 400 va, 2 x 45 v or 500 va
China transformer is very cheap and if you use bigger or
double must be enough to power you amplifier
If i dont use it for drive Totem Forest i will choose it
my transformer are arrived, so you cant join order
with me, maybe next time. 😀
" ... For the apex transformer (Genesis) you must email = steve.apexjr@prodigy.net
steve is a kind person, for payment you can pay by paypal or you can transfer by bca ( Rp. 50.000,- ) ..."
I just got two of Steve's torridal transformers (Genisis # TTO-13893-00 with primary (2) X 115 VAC and secondaries (2) X 45 VAC plus (1) X 14.75 - 0 - 14.75 and plus (1) X 17.x) ... total for two with domestic USA shipping was US$72.00. They both look real good. Both transformers have voltage output as advertised by measurement. Both should work out to be a bit more than 300 VA. I would say that these are a perfect fit for two NX-150 AussieAmplifier.com amplifier modules resulting in +/0/- 63 VDC rails and I would not have any qualms about using the alternate secondaries to power other devices as well.
If you have easier access to other torridal transfomers in your region, by all means get them. If not then I would advise getting Steve's / Apex's Genesis transformer ...
steve is a kind person, for payment you can pay by paypal or you can transfer by bca ( Rp. 50.000,- ) ..."
I just got two of Steve's torridal transformers (Genisis # TTO-13893-00 with primary (2) X 115 VAC and secondaries (2) X 45 VAC plus (1) X 14.75 - 0 - 14.75 and plus (1) X 17.x) ... total for two with domestic USA shipping was US$72.00. They both look real good. Both transformers have voltage output as advertised by measurement. Both should work out to be a bit more than 300 VA. I would say that these are a perfect fit for two NX-150 AussieAmplifier.com amplifier modules resulting in +/0/- 63 VDC rails and I would not have any qualms about using the alternate secondaries to power other devices as well.
If you have easier access to other torridal transfomers in your region, by all means get them. If not then I would advise getting Steve's / Apex's Genesis transformer ...
FastEddy those are 600va not 300 va. I have a 300va 45-0-45 transformer that is considerably smaller. Was that a mistype, or do you know something I don't? I mean each 45V lead is rated at 6.6 amps, thats 297va per rail, but using, for instance, the Plitron method, 594va total, or a 600va transformer. Given how transformers are generally rated, thats what its considered, a 600va transformer. I even mention this because when I read that it gave me pause, until I realized it wasn't right. I mean, each one would be fine for a two amplifiers and overkill for one. Am I missing something?
My Transformer Problem
Maybe fasteddy will use 1 torodial for 2 channel and 2 torodial
for 4 channel, maybe he got order for this so he run so fast! 😉
Or for best quality he build 1 torodial for 1 channel so he must
paid extra for psu, torodial but what mean of some penny if
he got SATISFACTION ( I Cant Get No - The Rolling Stanes )
Im confuse now about how many toro i will use it 😕
If i use 2 X 500 VA with 2 X 45 V can my house elctricity just
shut down because when i on my amp there will take a lot
electricity, What do you thinks guys ?
It will not funny if everytime i "on" my amp than my house
electricity must shut down first, maybe my wife will place
this amp in trash can
FastEddy said:
Maybe fasteddy will use 1 torodial for 2 channel and 2 torodial
for 4 channel, maybe he got order for this so he run so fast! 😉
Or for best quality he build 1 torodial for 1 channel so he must
paid extra for psu, torodial but what mean of some penny if
he got SATISFACTION ( I Cant Get No - The Rolling Stanes )
Im confuse now about how many toro i will use it 😕
If i use 2 X 500 VA with 2 X 45 V can my house elctricity just
shut down because when i on my amp there will take a lot
electricity, What do you thinks guys ?
It will not funny if everytime i "on" my amp than my house
electricity must shut down first, maybe my wife will place
this amp in trash can
![av 1000[1].gif](/community/data/attachments/79/79837-ea0ff23bd1ab80802bae1b1fb11f4f81.jpg?hash=6g_yO9GrgI)
- Status
- Not open for further replies.