alexw88
I can find 2 x 24V 400 VA and 2 x 33V 500 VA toroids at local Toroid
http://www.toroid.com.br/taudiotransist.html
Could you please inform which one fits best to BPA 300 ragarding clipping or heating?
Thanks in advance
JC
I can find 2 x 24V 400 VA and 2 x 33V 500 VA toroids at local Toroid
http://www.toroid.com.br/taudiotransist.html
Could you please inform which one fits best to BPA 300 ragarding clipping or heating?
Thanks in advance
JC
Hi,
33Vac cannot be used with these chipamps.
Your only choice is the 24Vac.
33Vac with 5% regulation and fed with nominal mains voltage will generate ~+-48Vdc, i.e. Vcc +|Vee| = 96Vdc.
Go back and look at the datasheet.
What does the datasheet say about maximum voltage when no signal is present?
And when signal is present what does the datasheet say for maximum voltage?
24Vac with 5% regulation and mains 6% above rated transformer input will give ~+-37V, i.e. Vcc + |Vdd| = 74Vdc.
Does this meet National's max rating for the chipamps?
This 24Vac transformer will probably idle ~ +-33 to +-34Vdc and sag to +-29 to +-31Vdc when delivering full power into 8r0. Now you can estimate the maximum power from the graphs.
It will probably sag to +-27 to +-29Vdc when delivering full power to 4r0. Again use the tables to estimate the maximum power.
33Vac cannot be used with these chipamps.
Your only choice is the 24Vac.
33Vac with 5% regulation and fed with nominal mains voltage will generate ~+-48Vdc, i.e. Vcc +|Vee| = 96Vdc.
Go back and look at the datasheet.
What does the datasheet say about maximum voltage when no signal is present?
And when signal is present what does the datasheet say for maximum voltage?
24Vac with 5% regulation and mains 6% above rated transformer input will give ~+-37V, i.e. Vcc + |Vdd| = 74Vdc.
Does this meet National's max rating for the chipamps?
This 24Vac transformer will probably idle ~ +-33 to +-34Vdc and sag to +-29 to +-31Vdc when delivering full power into 8r0. Now you can estimate the maximum power from the graphs.
It will probably sag to +-27 to +-29Vdc when delivering full power to 4r0. Again use the tables to estimate the maximum power.
JC Fardo said:
National made a very fine document called AN-1192 that describes BPA-200. They used 2 center-tapped 60 V transformers with 385 VA for 8 Ohm loads that produced ±37 V rails loaded. With those 770 VA they achieved 225 W of continuous output power into 8 Ohm.
There is also a table in that document, where the maximum supply voltages are given for different loads. It is not too difficult to convert them from BPA-200 to BPA-300.
You can use ±37 V (~2*30 V transformer) for loads down to 5,3 Ohm, ±32 V (~2*26 V transformer) down to 4 Ohm, ±28 V (~2*23 V transformer) down to 2,7 Ohm and ±20 V (~2*17 V transformer) for loads down to 1,3 Ohm.
Mains fluctuations will bring the ICs to their voltage limits and lead to increased power dissipation.
Hi guys!
I am new here, sorry on my bad english...
Respect to Alex and his amplifier!
I like simplicity of BPA 300 and planning to build one (two
).
Just wondering, can I use normal components (not SMD) around chip? Any problems with that?...oscillations or something similar?
I am planning to arange components on universal board...
And, yes I didnt find it anywhere...can someone compare sound of BPA300 with Aleph 5 or 2?
Please tell me for mistakes in my text, I will learn english faster then...
I am new here, sorry on my bad english...
Respect to Alex and his amplifier!
I like simplicity of BPA 300 and planning to build one (two
).Just wondering, can I use normal components (not SMD) around chip? Any problems with that?...oscillations or something similar?
I am planning to arange components on universal board...
And, yes I didnt find it anywhere...can someone compare sound of BPA300 with Aleph 5 or 2?
Please tell me for mistakes in my text, I will learn english faster then...
and you are going to monitor the output offset continuously while you listen and get out your seat to switch off whenever you decide it has become large enough to interfere with the sound quality or worse damage something.
Oh, I need to check both channels, I'll need to buy some more test equipment.
Oh, I need to check both channels, I'll need to buy some more test equipment.
Because the layout is very very similar to Alex's design. See the location of the Local decoupling caps and large MKP input cap. Is a copy of Alex's board. I dont know if he has copyright or not but the amp he designed is his intellectual property and for someone else to clone it for commercial reasons is not ok. Dont you agree?
In some cases I would agree but considering that Alex's board is in many ways a "copy" of Jeff Rowland's design, I don't agree in this case.
If someone copy a copy, who is worst?
Also, Alex him self don't want to sell the boards cause the time and effort it takes. He also states that the board is "inspired" by Jeff Rowland's and he gladly share his design on the web.
If someone copy a copy, who is worst?
Also, Alex him self don't want to sell the boards cause the time and effort it takes. He also states that the board is "inspired" by Jeff Rowland's and he gladly share his design on the web.
dudaindc said:
That is about right.
Calle, when we will be able to buy boards from you?
I have been checking your website often, but there has not been any updates on that front.
Cheers!
Well. I know that people is waiting for boards to be available, and I will make them available sometimes soon, hopefully before June. The website will most likely not be updated so much right now, I lost interest when Rysh didn't have more fantasy to put another Joomla-skin on his site. I will code my own or use something else prefabricated publishing system on it.
mikesnowdon said:
I think that the seller of this boards is the same as the one in this thread: http://www.diyaudio.com/forums/showthread.php?s=&threadid=142923 so I would think twice before placing an order...