5171/1930 is a fantastic drivers pair from Toshiba, but they are practically unavailable except some old stocks - they are not produced anymore as far as I know.
Lateral FETs are excellent drivers but they are also almost unavailable in decent quantities these days.
Sanken's 4883/1859 are very good as well and still available.
Lateral FETs are excellent drivers but they are also almost unavailable in decent quantities these days.
Sanken's 4883/1859 are very good as well and still available.
Cool
Just please bear in mind the feedback network is rather low-impedance (around 600 ohm), so when you test standalone, VAS is heavily loaded, so standalone measurements will not be correct. You need some OPS to have the thing running well.VAS transistors require the heatsinks. But it looks like the idle currents are somewhat higher than expected - let's see the voltage drop across the VAS emitter resistors.
Cool
Oh, standalone test stop here.
Is the NS out compatible?
VAS idle current is expected to be around 7mA, meaning you need to have 700mV across R20 or R23 (schematic from the post #20).
In case it's higher than that, you need to slightly increase the value of R17, R18.
Be careful with NS OPS - 7mA VAS current is a bit higher than it normally expects (5.5mA or so). So, probably it will make sense to set the VAS current down to 5.5mA, increasing R17, R18.
In case it's higher than that, you need to slightly increase the value of R17, R18.
Be careful with NS OPS - 7mA VAS current is a bit higher than it normally expects (5.5mA or so). So, probably it will make sense to set the VAS current down to 5.5mA, increasing R17, R18.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.