Hi,
you won't get 100W into 8r0 from +-42Vdc supplies.
If the amp PSU sags to +-42Vdc when on full load, then the remaining 2V may be just enough to get the 40Vpk needed to deliver the 5Apk that the 8r0 load needs.
I would suggest >=+-48Vdc for 100W into 8r0.
Most use a 35Vac transformer for this power spec. A good PSU combined with a good amplifier should get between 110W and 120W into 8r0.
A really good combination will get >200W into 4r0.
you won't get 100W into 8r0 from +-42Vdc supplies.
If the amp PSU sags to +-42Vdc when on full load, then the remaining 2V may be just enough to get the 40Vpk needed to deliver the 5Apk that the 8r0 load needs.
I would suggest >=+-48Vdc for 100W into 8r0.
Most use a 35Vac transformer for this power spec. A good PSU combined with a good amplifier should get between 110W and 120W into 8r0.
A really good combination will get >200W into 4r0.
since been operating
the particular circuit and variations for way too long now ....]
i would say :
-----darligtons to a circuit like that is simply out of the question....i van give you a million reasons for that (as devices .... as topology it really doesnt worth to try )
------ operation in >40 volt is generally not recomended ( to my opinion ) in circuits that are bootstrap operated and do not feature all modern technology like curent mirrors and CCS
----- it could work but for shure there might be instabilty issues especially at high power levels
----- to my friend jay cee !!!!!! i totally dissagree with you ( in a happy and friendly way ) and if i want to express my opinion about that i would say that an SZIKLAI / bootstrap is something like a tube circuit the performance is limmited , the amplifier is not acurate ,there is various limitations about a lot of things but the sonics produced by a circuit like that are simply unbeatable ....
very best regards to all ..... sakis
the particular circuit and variations for way too long now ....]
i would say :
-----darligtons to a circuit like that is simply out of the question....i van give you a million reasons for that (as devices .... as topology it really doesnt worth to try )
------ operation in >40 volt is generally not recomended ( to my opinion ) in circuits that are bootstrap operated and do not feature all modern technology like curent mirrors and CCS
----- it could work but for shure there might be instabilty issues especially at high power levels
----- to my friend jay cee !!!!!! i totally dissagree with you ( in a happy and friendly way ) and if i want to express my opinion about that i would say that an SZIKLAI / bootstrap is something like a tube circuit the performance is limmited , the amplifier is not acurate ,there is various limitations about a lot of things but the sonics produced by a circuit like that are simply unbeatable ....
very best regards to all ..... sakis
Hi,Adi_007 said:
is the transformer a 220:30Vac or 230:30Vac or 240:30Vac?
What is the transformer regulation?
What is your supply voltage?
What is the smoothing capacitance you intend fitting?
What is the quiescent current you intend drawing?
What amplifier topology do you intend using?
Then some one can model your amp/PSU and predict a power output.
Re: since been operating
My main issue with the sziklai is the stability. As for the sound.. well, i prefer my amps neutral, to only amplify without adding any colour of their own.
Having said all that, the P3A was the first discrete I built a long time ago now, and for such a simple circuit it delivers impressive results
There is no point in trying to push it beyond the basics though, going to more than 35V supplies and so on is asking for trouble.
sakis said:
My main issue with the sziklai is the stability. As for the sound.. well, i prefer my amps neutral, to only amplify without adding any colour of their own.
Having said all that, the P3A was the first discrete I built a long time ago now, and for such a simple circuit it delivers impressive results
There is no point in trying to push it beyond the basics though, going to more than 35V supplies and so on is asking for trouble.
oooooppppps
you are very correct ...thanks for pointing this out i will fix it tomorow ...
thanks !!!!
p robertson said:i'm afraid there seem to be a couple of errors on this pcb:- the drive to the vas transistor, and the connection of the vbe multiplier to the vas(no connection) hope u don't mind me pointing this out!
you are very correct ...thanks for pointing this out i will fix it tomorow ...
thanks !!!!
Re: Re: since been operating
hmmmm i am with you all the way ....similar to this when i tryied to make a P68 version working with MJ15003-4 i run in to stabiliy issues ..... but !!!!!! my clone of HILL CHAMELEON is working like hell without any stability or temperature issues producing lots of cheap power and average quality for a PA amplifier ....
so i think that sziklai is fine as long as you know what to expect and how to operate them ....
thanks jay cee
jaycee said:
My main issue with the sziklai is the stability. As for the sound.. well, i prefer my amps neutral, to only amplify without adding any colour of their own.
Having said all that, the P3A was the first discrete I built a long time ago now, and for such a simple circuit it delivers impressive results
hmmmm i am with you all the way ....similar to this when i tryied to make a P68 version working with MJ15003-4 i run in to stabiliy issues ..... but !!!!!! my clone of HILL CHAMELEON is working like hell without any stability or temperature issues producing lots of cheap power and average quality for a PA amplifier ....
so i think that sziklai is fine as long as you know what to expect and how to operate them ....
thanks jay cee
hello everybody.......within 3 weeks I managed to design a new layout for P3A amplifier but with 2 pairs of final transistors......I don't have the time to build it but maybe some of you have (and post some pictures if you want).......I made some minor modifications against the original schematic......I hope you will like it.
PS: in front of the pcb is the signal gnd and this will be connected directly to the main power supply.
sorry for my english, I translated with google
PS: in front of the pcb is the signal gnd and this will be connected directly to the main power supply.
sorry for my english, I translated with google
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Rodd Elliot will not be happy my dear
He sell these boards...he feed family earning money this way.... of course... you have rigth to make...but, even doing in an innocent, a blameless way....without knowing the consequences of this, you will not he helping the man.
My first moments in this forum (2004) was this way:
Someone asked the board and fast i made it and have posted..was published..soon several guys made copies...he (Rodd) dislike a lot... then i have asked moderators to remove... and i made that (personal decision) because he is a good guy that help us teaching things..someone that deserves our respect. (my opinion)
You do what you want...it is up to you.
http://sound.westhost.com/
Good luck.
regards,
Carlos
He sell these boards...he feed family earning money this way.... of course... you have rigth to make...but, even doing in an innocent, a blameless way....without knowing the consequences of this, you will not he helping the man.
My first moments in this forum (2004) was this way:
Someone asked the board and fast i made it and have posted..was published..soon several guys made copies...he (Rodd) dislike a lot... then i have asked moderators to remove... and i made that (personal decision) because he is a good guy that help us teaching things..someone that deserves our respect. (my opinion)
You do what you want...it is up to you.
http://sound.westhost.com/
Good luck.
regards,
Carlos
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it will be more wise to read the P3A tutorials to see each and every small detail of the construction ( since it perfectly analyzed ) before starting to modify things arround
your layout is not bad but has some small details here and there to be looked at ( small details can make the diference from a good amplifier to a perfect amplifier )
Beyond that you have some design troubles that you have to look at ...example adding miller caps to all drivers and VAs stage will not do you any good
Final advice will be to costruct the P3A as is if you like ( even better with original pcb ) and then go for EFP design and not an sziklai (CFP circuits are more easy to oscilate than EFP ) and if so go fro a prooven design and skip the expiraments
to modify one amplifier cannot be done with adding a few things of this and a few things of that .... it will take more than that ...since we dont talk about modify but actually redesign an amplifier ...
regards sakis
your layout is not bad but has some small details here and there to be looked at ( small details can make the diference from a good amplifier to a perfect amplifier )
Beyond that you have some design troubles that you have to look at ...example adding miller caps to all drivers and VAs stage will not do you any good
Final advice will be to costruct the P3A as is if you like ( even better with original pcb ) and then go for EFP design and not an sziklai (CFP circuits are more easy to oscilate than EFP ) and if so go fro a prooven design and skip the expiraments
to modify one amplifier cannot be done with adding a few things of this and a few things of that .... it will take more than that ...since we dont talk about modify but actually redesign an amplifier ...
regards sakis
It is good to do this way my friend...to be kind, cooperative with a good
man that is one of the main teachers we have, for free, in the internet.
This was decent, correct and fair..and you deserve my respect and congratulations dear Adi 007... if you mum is alive, should be pride of you... as you're a real man.
regards,
Carlos
man that is one of the main teachers we have, for free, in the internet.
This was decent, correct and fair..and you deserve my respect and congratulations dear Adi 007... if you mum is alive, should be pride of you... as you're a real man.
regards,
Carlos
Supporting livelyhood with audio
With the Chinese manufacturing power house and simple inventive process engineering of their engineers along with mega mass scale production and marketing
I doubt there is much left in supporting a livelihood through audio , unless there is an embargo , special duty or dumping tax in your country to protect you from the obvious - Big Fish Eats Small Fish , (though in this case the actual size of the life form does not matter their output facilities and government support does)
Suranjan
With the Chinese manufacturing power house and simple inventive process engineering of their engineers along with mega mass scale production and marketing
I doubt there is much left in supporting a livelihood through audio , unless there is an embargo , special duty or dumping tax in your country to protect you from the obvious - Big Fish Eats Small Fish , (though in this case the actual size of the life form does not matter their output facilities and government support does)
Suranjan
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