ok thanks, I still have an SU-V4 to repair, 8 pieces of new modules that work but don't adjust the clamp and bias, in fact they work but after a few minutes the protection opens because they are fake.
PS: it's a shame that the photographs are blurry, I'll wait anyway, if your modules work they will solve quite a few problems for many owners of this amplifier.
PS: it's a shame that the photographs are blurry, I'll wait anyway, if your modules work they will solve quite a few problems for many owners of this amplifier.
So your new fake modules work but not as intended? When the protection relay opens is that because the modules have self-destructed?
That's my experience with the Chinese modules but I've recently been told that there are some around that work correctly, I'd be glad to know which ones...
My DIY substitute has been satisfactory for my needs so far, schematic is almost identical to original STK8050.
I've since added a few pF, because I noticed some high frequency oscillations when testing, funnily these were not high in amplitude and only occurred with the amplifier's case open.
It works well, I've repaired 3 amplifiers (6 modules) so far and they've adjusted no worries and proven thermally stable. The couple of points that could be improved are a little more copper surface on first stage PNP transistor that runs a little hot, also the SMD Emitter resistors run hot when the amplifier is at full power on 4 Ohms load.
If I redesign one day I may try for an IMS version.
That's my experience with the Chinese modules but I've recently been told that there are some around that work correctly, I'd be glad to know which ones...
My DIY substitute has been satisfactory for my needs so far, schematic is almost identical to original STK8050.
I've since added a few pF, because I noticed some high frequency oscillations when testing, funnily these were not high in amplitude and only occurred with the amplifier's case open.
It works well, I've repaired 3 amplifiers (6 modules) so far and they've adjusted no worries and proven thermally stable. The couple of points that could be improved are a little more copper surface on first stage PNP transistor that runs a little hot, also the SMD Emitter resistors run hot when the amplifier is at full power on 4 Ohms load.
If I redesign one day I may try for an IMS version.
some modules that I bought like the ones in the photograph cause the voltages on pins 12/13/14/15/16 to be off and do not allow you to adjust the clamp and bias, the amplifier works but after a few minutes the protection opens.
the only STK8050 power packs that are original and compatible must have curves on pins 1-2 and 15/16, unlike pins 3 to 14. You can see from this photograph the one at the top called ALT is original Sanyo and you can see the curved pins , the one below is a replica and the pins are all curved the same.
the only STK8050 power packs that are original and compatible must have curves on pins 1-2 and 15/16, unlike pins 3 to 14. You can see from this photograph the one at the top called ALT is original Sanyo and you can see the curved pins , the one below is a replica and the pins are all curved the same.
Attachments
I recently got hold of a SU-V2 to repair, one of the STK8040 was toast. The other still kicking, I was curious enough to make a few comparative measurements.
Measurements are taken with both channels loaded at 6.5 Ohm. To be as fair as possible clamp voltage and quiescent current had previously been trimmed to specification on both channels. Amplifier's voltage selector is at 240V.
It's a very close match, the clone looks a little better for VCEsat than the original, other than that they're hard to tell apart.
CH1: Original STK8040 input at pin 16.
CH2: Original STK8040 output at pin 3.
CH3: Clone module input at pin 16.
CH4: Clone module output at pin3.
Measurements are taken with both channels loaded at 6.5 Ohm. To be as fair as possible clamp voltage and quiescent current had previously been trimmed to specification on both channels. Amplifier's voltage selector is at 240V.
It's a very close match, the clone looks a little better for VCEsat than the original, other than that they're hard to tell apart.
CH1: Original STK8040 input at pin 16.
CH2: Original STK8040 output at pin 3.
CH3: Clone module input at pin 16.
CH4: Clone module output at pin3.
