Now the question is how small can a slew become if you go smd all the way with a single pair of MT200 output devices with a total output of about 100 watts?
OS
I am using BC847 in NPN/PNP, there are also 2x PNP and 2x NPN versions. The BC's are very good.
There is a lot of fancy parts availible in SMD, a lot of them are comming from Infineon 😀
http://www.infineon.com/dgdl/Infineon-BFN27-DS-v01_01-en.pdf?fileId=db3a30431441fb5d011449c2ee1c0239
I have made a few projects in SMD and I see a step forward. The only thing which might be a bit problematic is linearity of the resistors.
Regards
I am using BC847 in NPN/PNP, there are also 2x PNP and 2x NPN versions. The BC's are very good.
There is a lot of fancy parts availible in SMD, a lot of them are comming from Infineon 😀
http://www.infineon.com/dgdl/Infineon-BFN27-DS-v01_01-en.pdf?fileId=db3a30431441fb5d011449c2ee1c0239
I have made a few projects in SMD and I see a step forward. The only thing which might be a bit problematic is linearity of the resistors.
Regards
Does anybody know if some good SMD jFET pairs exist (2x p-channel, 2x n-channel)?
n + p is also interesting, but this is the 2-nd priority.
n + p is also interesting, but this is the 2-nd priority.
That depends on the design. Symetri only has 8 semi's , 20 resistors ,and 5
caps. 75mm X 75mm is not out of the question.
full size would be 75 X 100mm (counting the MT's) .
First - These vindicators will be the last through -hole creations.
The END , besides power circuits and large electro's.
Second , I make the " (eye) IAMP" with 3 pair 264/MT's + I2C protection to get
up to speed. I think I'm going the diptrace route , as it has better SMD and
routing features.
Then , SMD will be primary.
PS - with 2 sides of a PCB , a 75 X 75mm SMD = a through-hole 75 X150mm.
OS
Those transistors are only 500mW and no information about Early Voltage and that is more important for transistors used as VAS then Cob.
By the way Cob is 5 pF, not so low.
Damir
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3503 is 2.6pf , SMD 496 is 5p ....
Most of my designs use either a baxandal or hawksford cascode. These HV semi's
are just the cascodes. The "active" semi's will still be BCxxx in SMD form.
I suppose I will just have to build my Leach amp input stages with SMD.
Listen and test.
PS - I have even used "lowly" MJE340/350 (20+ Cob) for my hawksford cascodes -
can't tell the difference. 😕
OS
Ahh ... BF722 / 723 =
2-3pf cob , 250V , 60 mhz , 1.2W.
As far as wattage , running the slew EF3 is easy.
Even 3mA VAS I will do. I've run both the wolverine and spooky @ <4ma
successfully. To-126's are cold to the touch <5ma.
OS
2-3pf cob , 250V , 60 mhz , 1.2W.
As far as wattage , running the slew EF3 is easy.
Even 3mA VAS I will do. I've run both the wolverine and spooky @ <4ma
successfully. To-126's are cold to the touch <5ma.
OS
Cob is really low, but again Early voltage is a problem, spice model shows VAF of 19.72 only, no good.
To126 devices actually take less space than their SMD equivalent on a board. The same goes for through hole electrolytic caps. A hybrid design makes the smallest board.
Are you already starting on a pc layout☺
Can't wait to get the listening result from Sam G circuit☺
Spooky will sound more punch in the bass. Some people like this, especially for live music.
"Hybrid Harmonics" will more easy listening, mid will more pleasing 🙂
But my favorite still Blameless with TMC compensation, very high slew rate 😎
Here is a suggested board layout for the Vindicator V(fa). I have assumed that C7 and C8 are non-polarised electrolytics.
View attachment Vindicator V(fa) V1.0 composite.pdf
View attachment Vindicator V(fa) V1.0 composite.pdf
The 75 X 100mm standard (below).
interface and mounting holes should be there.
If you want to do the V , cool . I'm doing the C first.
OS
Attachments
I'm working on slimmer designs to fit into a slim cabinet using 75mm wide heatsinks. Would these "slim" designs have oscillation or other issues?
Hari
Of course , how else would I see it built (you + Thimios) ??
All the "Corporation approved" 😀 IPS's (spook, symetri,sym ,, cfa X)
nice 40-50 X 75mm SMD boards.
My problem is the 1381/3503's .... they won't be around much longer.
I have run one of these IPS's with a pair of mpsa92/42's at 3ma. 200mw
dissipation is no issue with an EF3. So , SMD would work here.
Dadod says my picks have sucka$$ early voltage ...... hmmmm ?
But a hawksford cascode reduces early.
The HK990 just uses the Toshiba 1837/4793 pair. Nice to know they still make
these. On a PCB , one could just screw this pair together .... at even 5-6ma ,
no heatsink required.
OS
