Classic elektor desing , i have added only a 220 relay and thermal contact
Lazycat’s Original schematic is different than pcb.
680 ohm instead 100 ohm 22pf instead 5,6pf and additional 100pf. Tlvh431 and ccs already look the similar. I will try want is benefit them for amplifier
These small caps stabilize the amp in different ways. In simple terms the 22pF work as a speed limiter that keeps the amp below a certain speed so that it doesn't loose control. Used alone, there are minimum values that must not be lowered for stable operation.
Loading the VAS stage with 100pF capacitors to ground does something similar while also enabling safe operation during variation in load from the following stage i.e. the mosfet gates (which vary quite a bit during operation). And yes, if you load the VAS to ground via capacitors you can use a smaller capacitor in place of 22pF.
Feels nice to see someone tinkering around these designs from a decade ago.
Has it been confirmed elsewhere whether these Exicon transistors have integrated gate protection? I thought I found someone said they checked and the answer was yes, but from what I can see they don't in the models I could find. There's a hint of "has protection diode" on the website but they go on to say they mean use the body diode (or maybe they put another one in there, but I doubt it) for clamping which, of course is, is another kind of clamping altogether.
Not sure if laterals have a body diode... The datasheet claims absolute max Vgs of +/-14V, yet specify a gate-source leakage current for Vgs = +/-20V, which is worrying!
Think I'll have to investigate, I've a few knocking around.
--- well I've investigated - yes they have body diodes, and no there's no protection (well nothing stops the gate-source voltage reaching 14V other than a small leakage current in 10's of microamps.) I tested an ECF10N20 BTW (the obsolete TO3 package)
Think I'll have to investigate, I've a few knocking around.
--- well I've investigated - yes they have body diodes, and no there's no protection (well nothing stops the gate-source voltage reaching 14V other than a small leakage current in 10's of microamps.) I tested an ECF10N20 BTW (the obsolete TO3 package)
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I have finished my VSSA amp prototype. It works very stable and warm...
VAS bias:120mV Output Bias 182mA offset 0.65mV
*500VA 4x30VAC transformer
*5X4700uf each rail total: 94000uf
*ECX10N20 and 10P20 Lateral mosfets
*Over current protection
*DC offset protection
*Speaker on/off delay
*Thermal protection
*Soft start
*AC main filter with varistor and fuse
VAS bias:120mV Output Bias 182mA offset 0.65mV
*500VA 4x30VAC transformer
*5X4700uf each rail total: 94000uf
*ECX10N20 and 10P20 Lateral mosfets
*Over current protection
*DC offset protection
*Speaker on/off delay
*Thermal protection
*Soft start
*AC main filter with varistor and fuse
Attachments
OVER CURRENT
DC OFFSET
THERMAL TRACK
SPEAKER DELAY
SOFT START
AC MAIN FILTER
All in one board for power amplifier. Current can set for mosfet or transistor
I have pcb...
DC OFFSET
THERMAL TRACK
SPEAKER DELAY
SOFT START
AC MAIN FILTER
All in one board for power amplifier. Current can set for mosfet or transistor
I have pcb...
I have all vssa pcb+bom
*vssa amp pcb
*cap bank pcb
*all in one protection board
*soft start
*Upc1237 protection board
*vssa amp pcb
*cap bank pcb
*all in one protection board
*soft start
*Upc1237 protection board
Did you test it with some other amplifier??? How does it play???Years ago I built a VSSA too. Sound perfect
https://rpaudio.estranky.sk/fotoalbum/vssa/?photo=2
https://rpaudio.estranky.sk/fotoalbum/vssa/?photo=2
Yes i we did test it rotel and cambridge sugden and my jfet buffered composite feedback tda7293 ( https://www.diyaudio.com/community/...0-lsk489-composite-feedback-amplifier.413587/ )
For me;
1. Tda7293
2.vssa
3. Rotel
4. Cambridge
5. Sugden
For 60 years old audiophile;
1. Vssa
2. Tda7293
3. Sugden
4. Rotel
5. Cambridge
For me;
1. Tda7293
2.vssa
3. Rotel
4. Cambridge
5. Sugden
For 60 years old audiophile;
1. Vssa
2. Tda7293
3. Sugden
4. Rotel
5. Cambridge