Tubes amp

[siriuz 0]

@kube: yea i'm going to have an LED part. reminds me! i forgot to get purple LED from slt basement today RLED will depend on the voltage of the LED and how much current you want to feed it.

 

i'm really getting very forgetful!

[Kippei 0]

Koba weekdays should be open until 9 pm... I have became quite a regular there to the extend that the auntie and his son know me.

[squalle 0]

haha

 

same, I've become koba regular too. and always come late one

might have met you kippei

 

btw, go ahead with the PCB, but for sizes of components, kube you have to keep track what's the most easily available in singapore.

 

but, if only you guys wanna wait. I'm trying something now

wanna change the power stage (op-amp stage) to something else that can output more current

[siriuz 0]

i was thinking of the dynalo output stage actually

 

edit: but i think its abit overkill, so what's squalles idea ? the one you stated on headwize, the szekeres buffer?

Edited January 16, 2006 by siriuz

[squalle 0]

yea

 

but have to work on the DC offset too

else quite no point rite? solve 1 prob (too low of output current) and introduce another (DC offset, which solved with using output cap)

[siriuz 0]

what the 0.1uf cap between the tube and the opamp for arh?

 

edit: the dc-coupled version of the szekeres doesnt have an output cap, so why not?

Edited January 16, 2006 by siriuz

[squalle 0]

0.1uF is the high pass filter

 

coz it's going to op-amp from the B+ of the tube

 

haha gotta look for wat it means by the DC coupled of szekeres.

is it the one that the gate is biased at certain voltage? I am thinking along that line

[squalle 0]

this is the one that I am thinking too LOL

 

[siriuz 0]

yea thats the one

 

i'll go experiment around with drawing pcbs later

 

edit: but i heard szekeres very sensitive to power supply right ? the psu that the soha is designed around isnt that good

Edited January 16, 2006 by siriuz

[squalle 0]

ermmm

 

I've got myself another big trafo

and providing another seperate supply first

 

 

[huangyong 0]

i was thinking of the dynalo output stage actually

 

edit: but i think its abit overkill, so what's squalles idea ? the one you stated on headwize, the szekeres buffer?

siriuz, i raised this idea in Head-fi before, having hot debate there, what you need is balanced output to drive the output stage. I drwan one circuit before, let me dig it out.

[huangyong 0]

something like this

[1bit 0]

is this interpretation correct, huangyong?

the opamps make differential output then converted back to single output by the transistors?

 

i see, it makes the circuit complicated but you don't need high-pass filter anymore

nice

 

how do you end up with 511 ohm for the resistors vlue, btw?

i see that you try to make balanced inputs for the opamps

you might wanna add a resistor to the positive input of opamp #2 too, i think

perhaps 511/2 ohm to make it balanced as well

[squalle 0]

lost the bid in the last second of it

 

damn

[siriuz 0]

@huangyong: i still haven't figured out how any of that stuff works yet

 

@squalle: oh.. lost the bid arh. buy tube from well audio or koba better?