Are you sure D1 and D2 are right in your amp schema? I am just wondering if the cascade transistors can be on and/or the level shifters in saturation.
D1, and D2 are right. The input stage is working close to the saturation. But 0,6V Vce is enough for the properly selected transistor.
Sajti
D1, and D2 are right. The input stage is working close to the saturation. But 0,6V Vce is enough for the properly selected transistor.
Sajti
Be careful with BC550C/560C, look for quasi saturation region.
Be careful with BC550C/560C, look for quasi saturation region.
BC550C/560C is good for this application. BC337/327 would be better, but I can get the 550C/560C easier.
Sajti
How is the sound Sajti ???
I will let You know, once I will finish the amp.
Sajti
BC550C/560C is good for this application. BC337/327 would be better, but I can get the 550C/560C easier.
Sajti
It is not so simple, look at this thread please. http://www.diyaudio.com/forums/soli...i-saturation-measured-data-5.html#post4758150
It is not so simple, look at this thread please. http://www.diyaudio.com/forums/soli...i-saturation-measured-data-5.html#post4758150
Unfortunately not so simple. But my input stage is running with 1mA bias, and both 550C can handle it, with 0,6V Vce. Anyway I use Onsemi 550C and 560C.
Sajti
Unfortunately not so simple. But my input stage is running with 1mA bias, and both 550C can handle it, with 0,6V Vce. Anyway I use Onsemi 550C and 560C.
Sajti
You said it's easier to buy BC550C/560C for you, where do you buy them, I am interested to buy some.
Damir
You said it's easier to buy BC550C/560C for you, where do you buy them, I am interested to buy some.
Damir
From Mouser, about a year ago, maybe earlier. I had to clean up their stock, as Onsemi announced to finish manufacturing them
Sajti
Last edited:
Hi,
this project was started about 3months ago, to develop small sized amplifier, with high quality, and 120-140W/8ohms power.
Schematic attached.
Sajti
Very nice , a current mirrored cascoded VAS like my IC(eyesee) input module.
Run by a CFA front end.
The triple worries me , either decouple the driver/pre (or just the pre) with
a 4R-10R + 22u/.02uf R/C. Also make sure the driver/pre are stellar in the ft
spec ( 100mhz+) ...fast- fast !! outputs just the standard 20-45mhz variety.
Edit - I notice your passive DC blocking at the (-) CFA node. Very hard to hold offset down
since the low Z at this node (does not play well) with the passive method.
The input diamond beta be the major factor. I have always chosen a high Z positive op-amp
servo to tweak the input diamond DC bias by (as little as a few microvolts) to tweak the offset.
(below) tried this with a tested cfa one (built and ran). It seems to be the (only)
way for this type amp stage - my new one will use this. THD is still single digit
PPM with the positive FB servo.
OS
Attachments
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
- Home
- Amplifiers
- Solid State
- V6 amplifier