TA-100W follow-up "work around"

[luke9099]

stk 100

I'm inclined to think that the stk100 is based on the full complementary output circut, because data sheet indicates stk 100 as full complementary circuit on the left side of the column. If it is quasi complementary it would show on the right side of the column indicating it as such.

This particular data sheet shows up to stk80 module, and it is indicated as having full complementary circuit.

http://pdf1.alldatasheet.com/datasheet-pdf/view/89338/ETC/STK0080.html

 

[EchoWars]

I'm inclined to think that the stk100 is based on the full complementary output circuit

You are correct...I was misreading the data sheet. Many of the older STK's had a quasi-complementary part, and a full complementary part designated by the 'II' after the number. I assumed the 0100 was the same way, and it is not.

As far as your data sheet link, it does not include an equivalent schematic, which I'd have to see before I used the 0100 part and not the 0100II part.

Have you measured the bias current in the new devices? There's a lot of bogus STK modules out there that have no bias circuitry.

 

[luke9099]

bias current

No, yes I have completely overlooked possibility of having fake modules. I've purchased fake transistors in the past. Namely Sanken transistors. I'll measure the bias current, next time I work on the device. Thanks.

 

[luke9099]

Data sheet shows internal schematic for stk80, 60 and so on. I believe ve stk100 is similar.

 

[ManyMoonsAudio]

I bought a few bogus amp packs from your recommended source a couple years ago.... I thought I was getting a great deal. I ran a SX-780 up to about 20 watts and then the channel just died......twice.

 

[EchoWars]

Data sheet shows internal schematic for stk80, 60 and so on. I believe ve stk100 is similar.

Check the link you gave...there's nothing of the sort.

 

[luke9099]

http://html.alldatasheet.com/html-pdf/89338/ETC/STK0080/97/2/STK0080.html

You'll have to click your way to it. You'll eventually get to internal schematic part. I don't know of a way to get to it directly.

 

[luke9099]

Paul, can you tell me which exact source you had problem with?

 

[ManyMoonsAudio]

electronix.com

 

[luke9099]

stk0100

Electronix , that is the place where I got my sk0100. So far, I haven't cranked up past 3 watt. Now I'm afraid to go beyond that. Ones that are original, seller indicates "original Sanyo". I guess others are generics.

 

[luke9099]

Measured voltage drop across .35 ohm emitter resistors. Left channel reads 18mv. Right channel around 34 mv.

 

[luke9099]

Actually .7 ohms, measured both resistors.

 

[EchoWars]

If both devices had measured about 34mV, I'd have said you might have a couple of decent modules, but with one measuring 1/2 of the other, I gotta wonder what it is you might have. I wouldn't hesitate to connect some dummy loads and crank it up to see what happens...if it's gonna pop, I'd rather it happen on the bench while connected to a dummy load.

And just because a seller claims 'Original Sanyo' doesn't make it so. I cannot find a STK0100 from a source that I'd trust. As for the STK0100II, it is much more expensive ($45 ea + shipping).

I have an ailing KA-9100 here with supposedly dead modules in it. If they prove to be blown, I may go with the Sanken STD03 devices, and I may take a look at the STK0100II. Haven't decided.

 

[luke9099]

Also, another thing I noticed; there is a constant low level noise with the volumn level set to the lowest. When volumn is crancked up, sounds pretty decent. But noises are alway there, but noise level does not go up with the change in volumn.

 

[EchoWars]

Disconnect the amp from the preamp with the rear panel switch and see what happens to the noise.

 

[luke9099]

Disconnected amp from preamp, and noise is there.

 

[SicMan]

Thanks for checking. Next dead 9100 that shows up here, I'll track down some of the STD03N's & STD03P's.

Hi Glenn, reviving this old thread. I have a 9100 running with one channel up on SAP16's which are the obsolete ones and the more robust xistors and new caps, and a 10 turn pot for bias adjust. It's running great.

I have some 0.33 ohm resistors 10W and am going to order a few STD03's this week or next and do the other channel in this 9100 then start running some more tests. The SAP16's run very cool driving 4 ohm speakers. I let my son take it to a party and run it for a test. Didn't even get hot. So next phase test soon.

cheers

John M

 

[srinath]

Reviving this relic thread - cos 2 reasons ...

Dead KA 9100 with 1 dead TA100 cane through my hands and got returned to owner in a bag a few weeks ago.

2. The stk0100ii mentioned here - lives in its original housing a fisher ba6000 - which I am scratching on, and was wanting to find the complimentary transistors to the 2sd718 which as per internet is a 2sb688 but I also see 2sd758's on other threads here.

Which would be the best option ?

Thanks.
Srinath.

 

[EchoWars]

Got your numbers mixed up...the D718 and B688 are full-blown output transistors. The D758 is a TO-220 driver.

 

[srinath]

The ba6000 fisher has 2sb718 X 4 and 2sd758 X 2 per channel.

And on ebay they seem to be selling - 2pair (4pcs) 2SB688 & 2SD718 Transistor B688 & D718 - Free Shipping -
http://www.ebay.com/itm/2pair-4pcs-...842?pt=LH_DefaultDomain_0&hash=item27cd3a7102

OK so what am I missing here ?

Also this amp blew the output when I knocked on the case when its 1 meter was dead.
What could have made that happen and how to fix - can it be a transistor listed above. Or other problem.

Cool.
Srinath.