Yes,but this speaker is only for test,for long listening i have 15" speaker in right case 😉And a shoe box speaker cabinet. You are my newest hero!
Because it's good amp,it works ok 😉Hi Acca.
Your job is wow! I love the mess with those hanging parts and am amazed that you made it work without any problem.
Darlingtons are nice, but due to positive tempco and low fT they were avioded in the first place. I suggest you use a Vbe multiplier with them and fix the extra transistor to the main heatsink.
Please use the VSSA thread or the FET-hex Explendit thread to post your layout as this thread is focused only on Lateral FET designs.
Thanks.
shaan
I use parts from old TV.Only darlingtons are boughted.
For class B Vbe mult. is not needed.I can make it,but i like simple things.
Ok,when i finish.I'll post pcb.
Regards
Last edited:
High tones are wery good.For me this amp is better than TDA7294 🙂
It have crystal sound 😉
Bass is not high but this is because i use 100uF instead of 2200u.
And cheaper 😉
It have crystal sound 😉
Bass is not high but this is because i use 100uF instead of 2200u.
And cheaper 😉
Last edited:
Hi Acca.
I am sure that the quality of sound you are experiencing from the class-b darlington vssa is very good.
I have simulated the amp with darlington outputs (TIP142/147 models from Onsemi). The overall increase of distortion is 3 times higher than the FETs, in class-ab even with emitter resistors in the darlingtons. With zero bias class-b this can only get worse.
If you really want to know what the amp is capable of then you must try Laterals, in class-ab (no need for Vbe multiplier for Latfets in Class-AB either, just two 1N4148 in series and it's done).
Happy listening.
shaan
I am sure that the quality of sound you are experiencing from the class-b darlington vssa is very good.
I have simulated the amp with darlington outputs (TIP142/147 models from Onsemi). The overall increase of distortion is 3 times higher than the FETs, in class-ab even with emitter resistors in the darlingtons. With zero bias class-b this can only get worse.
If you really want to know what the amp is capable of then you must try Laterals, in class-ab (no need for Vbe multiplier for Latfets in Class-AB either, just two 1N4148 in series and it's done).
Happy listening.
shaan
Shaan did try BJT outout with Vbe multiplier??? By me it is top notch...and i try Latfet...
Marc
Marc
Hi Marc.
No objection to your opinion.
I'm just tryin' to keep this thread as clean and action-filled as I(we) can.
It's been proven by many that with six active parts that you may already have in your junkbox, you can build and listen to the Amp of the Decade, without busting your budget.
No objection to your opinion.
I'm just tryin' to keep this thread as clean and action-filled as I(we) can.
It's been proven by many that with six active parts that you may already have in your junkbox, you can build and listen to the Amp of the Decade, without busting your budget.
I have built two different versions, so far, and I also have Lazy Cat's modules from the GB in his VSSA thread. The one I listen to almost daily is the one closest to Shaan's original schematic (with compensation caps added, and a highly filtered power supply). I am still experimenting, but I do believe that this amplifier benefits from a clean supply, more so than others. I also hope to try some of the other versions, like Marc's (well, Borys/Marc's anyway... 😀 )...with six active parts that you may already have in your junkbox, you can build and listen to the Amp of the Decade, without busting your budget.
Attachments
In theory.Hi Acca.
I am sure that the quality of sound you are experiencing from the class-b darlington vssa is very good.
I have simulated the amp with darlington outputs (TIP142/147 models from Onsemi). The overall increase of distortion is 3 times higher than the FETs, in class-ab even with emitter resistors in the darlingtons. With zero bias class-b this can only get worse.
If you really want to know what the amp is capable of then you must try Laterals, in class-ab (no need for Vbe multiplier for Latfets in Class-AB either, just two 1N4148 in series and it's done).
Happy listening.
shaan
Practice,it's better than voltage feedback (quality) but worse in ofset.
I make another one amp with voltage feedback,and with small volume quality is worse than your amp.On small volume your amp sound's very good.You can try make comparison like me.Bias it in class B and see difference.😱
I can't make offset to 0V.In 0V region it changes from + to - 20mV.When heat up,it change to 1V😕
But quality is very good,even on small output voltage 😉
I used different darlingtons 😀 (BDX33C + TIP125)
I tried it with SMPS.Works very good,but i must change few parts to get better DC ofset.AC ofset ok.Maybe to try all trans. on same heat sink.
Attachments
Last edited:
I tried to change VAS with transformer 😀
And only two output transistors 🙂
(but this is not thread for this)
Add:
Your amp simply shut down if one rail fail 😉
And only two output transistors 🙂
(but this is not thread for this)
Add:
Your amp simply shut down if one rail fail 😉
Last edited:
I used resistor values from your amp,and bias is changed.It's ok now,even with different output transistors 🙂.
Input sens. 1.2Vrms
Later I'll post some pictures,to see my small module.
Input sens. 1.2Vrms
Later I'll post some pictures,to see my small module.
Hi Acca.
Please use the >FET-hex Explendit< thread for posting your reports on darlington vssa.
This thread is dedicated to PCB designs for the Lateral FET version only.
If you will not be using Laterals then please don't post here.
Thank you.
Please use the >FET-hex Explendit< thread for posting your reports on darlington vssa.
This thread is dedicated to PCB designs for the Lateral FET version only.
If you will not be using Laterals then please don't post here.
Thank you.
Last edited:
Today I just finish to mod my PeeCeeBee (the old 1 pair output)...
I changed VAS to BD139-140 ---> stable without compensation caps & without zobel
thanks to Shaan for this tips
I also change 2k2 / 100R resistor to 1k5 / 47R, I want higher gain...
but no the result is not so high (not much different)
I must find what wrong with me 😀
The good news is the sound is still so good 🙂 ...
for everyone that want to build this PeeCeeBee
just go for what Shaan says and
prepare to surprise because of the sound of this amp
About the big brother I not continue it yet,
Shaan, it is okay to post 2 pairs output here because
it is not the 6 transistors magic
they are 8 transistors magic 😀
I changed VAS to BD139-140 ---> stable without compensation caps & without zobel
thanks to Shaan for this tips
I also change 2k2 / 100R resistor to 1k5 / 47R, I want higher gain...
but no the result is not so high (not much different)
I must find what wrong with me 😀
The good news is the sound is still so good 🙂 ...
for everyone that want to build this PeeCeeBee
just go for what Shaan says and
prepare to surprise because of the sound of this amp
About the big brother I not continue it yet,
Shaan, it is okay to post 2 pairs output here because
it is not the 6 transistors magic
they are 8 transistors magic 😀
Ok,no problem,theme is only for fet design. 😉Hi Acca.
Please use the >FET-hex Explendit< thread for posting your reports on darlington vssa.
This thread is dedicated to PCB designs for the Lateral FET version only.
If you will not be using Laterals then please don't post here.
Thank you.
p.s. Amp work even with clasic bjt 😉
Yes. True for all variations of the VSSA. Phenomenal, isn't it?
No problem. All that matters is less phase, adding a buffer or driver stage increases phase difference between the input signal and the feedback signal. Paralleling devices doesn't increase phase, but may limit the highest frequency response which will still be above 1MHz.
You may even post one with parallel inputs, but not a CFP or diamond input. 😉 😀
Of course it works, it even works with BIGBT, CFP, lateral mosfets, triple emitter follower outputs, you name it. That's the one and only VSSA front-end enabling all these threads.
