AndrewT said:
No, I'm not worrying about the capacitor charging current. It's that as long as the capacitors are empty no voltage will develop over the transformer. Without enough voltage over the transformer when the soft start cuts out, the flux doubling effect will still be there if the caps haven't charged enough.
Using a small value resistor and a short time should work very well. Even if a resistor value as low as 10 ohms is used (230V mains and ~45V secondaries) the secondary current will be only 60A or so per rail, hardly a problem for the recitfier or caps. The caps will be charged quite a bit in the order of 100ms if not using insane amounts of capacitance.
And if the caps now are practically fully charged by the soft start the length of the soft start won't matter much for the energy absorbed by the soft start resistor.
bigpanda said:
Greetings Ailuropoda Melanoleuca, nice to hear from you again.
If the TIP121 is free then no problemo. Just watch the pin-outs.
The only reason I used a BD679 was for the gain offered by the darlington allowing the use of minimum base emitter current. So anything with high gain will do.
Cheers
Quasius Amplificatus Economus
quasi,
I sent you an email to your website, I got no response.
Now that I can catch you here before you "run" away would like to answer some queries that still bothering me.
I found it interesting that you still use quasi-complementary pair in your design, I suppose during the earlier days pnp trans were expensive that is why quasi was chosen. I understand some amp which use quasi compl pr prove to sound very good gathered from users response, eg Naim Nap 140 and their clones, fairly old design but still good.
You may like to explain to me whether there is any technical advantages why you still use this config over purely compl. pair.
Also, do you feel the sound of quasi compl is "superior" to pure compl pair? or it is just different?
Thanks.
I sent you an email to your website, I got no response.
Now that I can catch you here before you "run" away would like to answer some queries that still bothering me.
I found it interesting that you still use quasi-complementary pair in your design, I suppose during the earlier days pnp trans were expensive that is why quasi was chosen. I understand some amp which use quasi compl pr prove to sound very good gathered from users response, eg Naim Nap 140 and their clones, fairly old design but still good.
You may like to explain to me whether there is any technical advantages why you still use this config over purely compl. pair.
Also, do you feel the sound of quasi compl is "superior" to pure compl pair? or it is just different?
Thanks.
Hello Ttan98,
I sent you an email about 30 minutes ago, sorry about the delay but I get quite a few emails and my life at the moment is quite busy.
The only reason I designed a quasi-complementary design is because I gathered hundreds of n-channel FETs over time. I thought I should put them to good use without spending any more money. This FET amp became quite popular with literally hundreds of modules built around the world so I decided to extend the quasi-complementary design to a bi-polar version as well. I also happened to have plenty of NPN TO3 transistors so I decided on a TO3 output stage. This amp is found in the thread "brother of quasi".
At the same time I happened to register on DIY Audio and it made sense to call myself Quasi. The rest as they say is history.
Anyway a complementary design should perform better provided the N and P devices are very well match for all parameters. This is because pure symmetry is maintained. But N channel devices are plentiful and cheap so with good design excellent results can be obtained with a quasi-complementary design.
At the end of the day it's all in the listening. My personal view is that provided the design of the amp is sound* (layout included) the power supply will make the critical difference.
Cheers
Quasius lastus foursomethiungus
* no pun intended.
I sent you an email about 30 minutes ago, sorry about the delay but I get quite a few emails and my life at the moment is quite busy.
The only reason I designed a quasi-complementary design is because I gathered hundreds of n-channel FETs over time. I thought I should put them to good use without spending any more money. This FET amp became quite popular with literally hundreds of modules built around the world so I decided to extend the quasi-complementary design to a bi-polar version as well. I also happened to have plenty of NPN TO3 transistors so I decided on a TO3 output stage. This amp is found in the thread "brother of quasi".
At the same time I happened to register on DIY Audio and it made sense to call myself Quasi. The rest as they say is history.
Anyway a complementary design should perform better provided the N and P devices are very well match for all parameters. This is because pure symmetry is maintained. But N channel devices are plentiful and cheap so with good design excellent results can be obtained with a quasi-complementary design.
At the end of the day it's all in the listening. My personal view is that provided the design of the amp is sound* (layout included) the power supply will make the critical difference.
Cheers
Quasius lastus foursomethiungus
* no pun intended.
dudaindc said:Happy "Quasi-50" Birthday!
(Thanks for sharing a great deal of time & knowledge with us...)
Thanks but not 50 yet. Tomorrow is my last 40 something birthday. not 50 yet not 50 yet not 50 yet .....
Thanks everyone else too. Good to hear the most powerful ACTRK600 (more like ACTRK900) is still going Dan.
Cheers
Quasius notus fiftius yetus.
You now Quasie, when the 5 is there you will receive a lot of presents.
Probably plenty of beer and a ticket for the movies.
Some will bring you a botlle of wine and others try to surprise you.
I myself got a new "frontdoor" allmost five years back.
I still have stuf from that party allthough I can't remember what?
Any way, enjoy.
Happy Birthday
Tarzan
Probably plenty of beer and a ticket for the movies.
Some will bring you a botlle of wine and others try to surprise you.
I myself got a new "frontdoor" allmost five years back.
I still have stuf from that party allthough I can't remember what?
Any way, enjoy.
Happy Birthday
Tarzan
