Re: Littl' B
Rock,
Your schematic calls for regulated 5V. Would a plain jane 7805 work, or will it need a bit more?
ROCKMANDRAKE said:
Rock,
Your schematic calls for regulated 5V. Would a plain jane 7805 work, or will it need a bit more?
Regulator
Hi Greyskale,
you can use 7805 regulator ( ref: MC78T05CT - i max 3A )
Please don't forget this amp needs (at least) 94/95db sensitivity loudspeakers ...
Rock
Hi Greyskale,
you can use 7805 regulator ( ref: MC78T05CT - i max 3A )
Please don't forget this amp needs (at least) 94/95db sensitivity loudspeakers ...
Rock
my speakers are 92db sensitive, so not quite 95/96, but too close to not try your design😉. Rock I hate to keep asking questions, but I guess I'm just being thorough 😀... On your schematic there is a - PSU input with no rating... I want to assume this is the PSU gnd, but then again I don't really like to assume. Dual supply? This is also connected to the chassis gnd no?
Thanks again Rock!
Thanks again Rock!
Re: Littl' B
There are some things missing from your schematic because of which you either don't get low offset or you don't get any useful power - your bias current flows directly through your speaker, which means your beloved amp may kill your beloved speakers eventually.
BTW 350mV DC across a high eficiency speaker (which normally has very low cone excursion) may well not do permanent damage but it will drive your speaker into nonlinear excursion.
BTW2 resistor values in your circuit also depend on transistor temperature, signifficantly so.
ROCKMANDRAKE said:
There are some things missing from your schematic because of which you either don't get low offset or you don't get any useful power - your bias current flows directly through your speaker, which means your beloved amp may kill your beloved speakers eventually.
BTW 350mV DC across a high eficiency speaker (which normally has very low cone excursion) may well not do permanent damage but it will drive your speaker into nonlinear excursion.
BTW2 resistor values in your circuit also depend on transistor temperature, signifficantly so.
PSU
Hi Greyskale, Ilimzn,
you're absolutely right , - PSU is the PSU Gnd ...
92db sensitivity seems to be a bit low but why not !!!
Ilimzn,
please note that a large majority of "old" germanium design suffer from DC offset at the output but without any established consequence on loudspeaker longevity !!
Rock
Hi Greyskale, Ilimzn,
you're absolutely right , - PSU is the PSU Gnd ...
92db sensitivity seems to be a bit low but why not !!!
Ilimzn,
please note that a large majority of "old" germanium design suffer from DC offset at the output but without any established consequence on loudspeaker longevity !!
Rock
Zzonbi - I built the SE class A amp you linked to at http://diyaudioprojects.com/Solid/ZCA/ZCA.htm.
Is a smooth amp - my LM3886 amp sounds sharp when compared to it - its good to have a huge supply of k1058s laying around for those sort of projects!
Is a smooth amp - my LM3886 amp sounds sharp when compared to it - its good to have a huge supply of k1058s laying around for those sort of projects!
Hello Mikefromaus, an amp which you have build is interesting. But, schematic does not show transformer output voltage and VA values. What trafo have you used?
thanks
thanks
"Zzonbi - I built the SE class A amp you linked to"
Hello Mike, nice to see what a single transistor is capable of doing in the right hands. I like its simplicity. Now if only it would heat less, besides the music that is ;-)
Hello Mike, nice to see what a single transistor is capable of doing in the right hands. I like its simplicity. Now if only it would heat less, besides the music that is ;-)
HI
I just purchased the power transistors at the Ebay from UK .
I will try these amplifier !
I hope I will fund the rest of the transistors to .
Greetings
I just purchased the power transistors at the Ebay from UK .
I will try these amplifier !
I hope I will fund the rest of the transistors to .
Greetings
Hello
Before I collect the parts I would like to know did anyone else built these amplifier or something similar .All the parts available on Ebay and Parts Connexion .
If yes would you please comment the sound of the amp .
Thank you very much .
It really look simple but better to ask than after sorry .
Greetings
Before I collect the parts I would like to know did anyone else built these amplifier or something similar .All the parts available on Ebay and Parts Connexion .
If yes would you please comment the sound of the amp .
Thank you very much .
It really look simple but better to ask than after sorry .
Greetings
I have built something alike down the sixties (1964)
And i have found the sound delicious.
Well.... audio equipments those days were not so nice... at least transistorized were not good...so.... something reasonable could appear as excelent compared to the things we had into those old days.
I wish i had some Germanium here to build it once again.
regards,
Carlos
And i have found the sound delicious.
Well.... audio equipments those days were not so nice... at least transistorized were not good...so.... something reasonable could appear as excelent compared to the things we had into those old days.
I wish i had some Germanium here to build it once again.
regards,
Carlos
Germanium SE with output transformer
Hi,all
here I post a shematics is using Germanium transistor to build one single-ended amp.
It works without global negative feedback loop...
it sounds very fantasy that out of my imagine...
itsn't like silicon BJT or MOSFET's...more closely to vacuum tube's
the output stage is about 10Watt wasted with heat,so the transistor need one large aluminium heatsink(0.8KG or more)...
2SJ77 is mosfet manufactured by janese HITACHI.
3AD30C is a chinese germanium transistor,Pmax>=20W,
Vceo>30V,HFE=50~100...you can according the data take place with other germanium power transistor...
have fun!
WINCO
Hi,all
here I post a shematics is using Germanium transistor to build one single-ended amp.
It works without global negative feedback loop...
it sounds very fantasy that out of my imagine...
itsn't like silicon BJT or MOSFET's...more closely to vacuum tube's
the output stage is about 10Watt wasted with heat,so the transistor need one large aluminium heatsink(0.8KG or more)...
2SJ77 is mosfet manufactured by janese HITACHI.
3AD30C is a chinese germanium transistor,Pmax>=20W,
Vceo>30V,HFE=50~100...you can according the data take place with other germanium power transistor...
have fun!
WINCO
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