Welcome, Guest. Please login or register.

December 07, 2021, 10:24:09 PM

Login with username, password and session length

Recent Posts

 

Author Topic: STK Chips....why there´s nothing about them here?  (Read 13592 times)

dsmnoisemaker

  • Regular
  • **
  • Posts: 24
  • Chip Points: 2
    • View Profile
STK Chips....why there´s nothing about them here?
« on: January 18, 2009, 10:34:59 PM »
hi all, i´ve been checking out different options of chip amps (or maybe called cheap amps?),
and one that caught my interest were the STK402 series...they go from 2x25W up to 2x120W and look pretty nice from power dissipation and thd point of view..i´ve searched a lot about them, but there´s no more info than the datasheets..and nothing in this forum..

anyone had experiences with STK chips? are they good enough?

dsmnoisemaker

  • Regular
  • **
  • Posts: 24
  • Chip Points: 2
    • View Profile
Re: STK Chips....why there´s nothing about them here?
« Reply #1 on: January 20, 2009, 05:14:23 PM »
interesting....no replies about them.. are they a tabu or something?

Boprikov

  • Chipper
  • *
  • Posts: 9
  • Chip Points: 0
    • View Profile
Re: STK Chips....why there´s nothing about them here?
« Reply #2 on: January 21, 2009, 03:47:22 AM »
interesting....no replies about them.. are they a tabu or something?

I don´t know why, but most solid state guitar amp manufacturers seem to use TDA chips instead. Maybe STK chips are more suitable to use in home hifi equipment. They may even perform better from sound quality standpoint, but TDA:s may be more ruggedly designed regarding low speaker impedances and such. Just maybe, i don´t know so much about STK:s... TDA:s are more familiar to me, because they are quite cheap.


But i have seen somewhere a guitar amp design using a STK chip, and  i see no reason why not to try and build a guitar amp using STK.


teemuk

  • SSGuitar Global Mod
  • Legendary
  • ****
  • Posts: 1075
  • Chip Points: 282
    • View Profile
Re: STK Chips....why there´s nothing about them here?
« Reply #3 on: January 21, 2009, 08:55:21 AM »
This is based on my memory so the information could not be accurate but here’s what I think are some of the reasons for unpopularity

-The production of great amount of STK series audio amplifier chips was discontinued already few years ago and the STK audio amplifier chips that were on the market (assuming there even were any) were rather old-fashioned designs. The products that are on the market now are new designs, not known well yet and their datasheets are hard to find
- They always were quite expensive
- The STK series chip amps always seemed to require lot more external components than the competing LM and TDA series chips/circuitry. They also had much more complex configuration (more pins that had to be used to make a working circuit)
- They often came in forms that contained two or three amps inside the same chip, which is not very useful in typical mono applications that guitar amps are
- The chip amp craze has been pretty much revolving around the “gainclone” variations. A great deal of people is reluctant to experiment with something new. Part of that is because trying some “obscure” design means you pretty much work by yourself and will not get similar support in your project as gainclone builders tend to get from their peers.

dsmnoisemaker

  • Regular
  • **
  • Posts: 24
  • Chip Points: 2
    • View Profile
Re: STK Chips....why there´s nothing about them here?
« Reply #4 on: January 21, 2009, 05:22:34 PM »
well..so far i had no trouble finding datasheets for stk chips..

for example..check this one out:
 http://www.steveselectronics.com/files/STK402-120.pdf

it´s a 80+80W, +-39V, 6 Ohms, 15 pin power amp..it looks pretty good from a thermal and performance standpoint, and here in santiago it costs 10 bucks!!

In theory, you can build a really powerfull stereo guitar amp, and even use current feedback..unless you use both channels in BTL configuration...

jfetter

  • Regular
  • **
  • Posts: 48
  • Chip Points: 20
    • View Profile
Re: STK Chips....why there´s nothing about them here?
« Reply #5 on: January 22, 2009, 11:42:59 AM »
I attempted to use them but found they were difficult to obtain. They also did not seem stable as far as future availability.

dsmnoisemaker

  • Regular
  • **
  • Posts: 24
  • Chip Points: 2
    • View Profile
Re: STK Chips....why there´s nothing about them here?
« Reply #6 on: January 22, 2009, 01:19:05 PM »
guys..if i design a PCB for it, will you help me to debug it?
i´ve had experience designing layouts for preamps, but i´ve never designed a pcb for a power amp..AFAIK they are more sensitive than preamp layouts...

wil you help me?

dsmnoisemaker

  • Regular
  • **
  • Posts: 24
  • Chip Points: 2
    • View Profile
Re: STK Chips....why there´s nothing about them here?
« Reply #7 on: January 22, 2009, 01:48:55 PM »
I attempted to use them but found they were difficult to obtain. They also did not seem stable as far as future availability.

Well here in chile seems to be plenty of them and they are pretty cheap..in fact LM3886/4780 are very hard to get, and they cost the same or more than a STK chip of the same power..

It seems that the main reason for not using STK is availability..and not quality..but i´m not planning to make them massively..just 1 or 2 of them..

jfetter

  • Regular
  • **
  • Posts: 48
  • Chip Points: 20
    • View Profile
Re: STK Chips....why there´s nothing about them here?
« Reply #8 on: January 23, 2009, 09:02:13 AM »

What distributor or seller do you use?

I attempted to use them but found they were difficult to obtain. They also did not seem stable as far as future availability.

Well here in chile seems to be plenty of them and they are pretty cheap..in fact LM3886/4780 are very hard to get, and they cost the same or more than a STK chip of the same power..

It seems that the main reason for not using STK is availability..and not quality..but i´m not planning to make them massively..just 1 or 2 of them..

dsmnoisemaker

  • Regular
  • **
  • Posts: 24
  • Chip Points: 2
    • View Profile
Re: STK Chips....why there´s nothing about them here?
« Reply #9 on: January 23, 2009, 11:32:32 AM »
for this i´ll use this seller:

http://www.cm2.cl/busqueda.php?b=stk402&btn=Buscar

they have a wide variety of chipamps , but no LM4780...

jfetter

  • Regular
  • **
  • Posts: 48
  • Chip Points: 20
    • View Profile
Re: STK Chips....why there´s nothing about them here?
« Reply #10 on: January 27, 2009, 10:55:04 AM »
Do you think they may be a NOS buyout (new old stock)?


I attempted to use them but found they were difficult to obtain. They also did not seem stable as far as future availability.

Well here in chile seems to be plenty of them and they are pretty cheap..in fact LM3886/4780 are very hard to get, and they cost the same or more than a STK chip of the same power..

It seems that the main reason for not using STK is availability..and not quality..but i´m not planning to make them massively..just 1 or 2 of them..

dsmnoisemaker

  • Regular
  • **
  • Posts: 24
  • Chip Points: 2
    • View Profile
Re: STK Chips....why there´s nothing about them here?
« Reply #11 on: January 27, 2009, 11:28:36 AM »
well i hope so!!
i know that there are a lot of fake stk chips so i have to check them out before buying

J M Fahey

  • SSGuitar Global Mod
  • Legendary
  • ****
  • Posts: 4142
  • Chip Points: 429
    • View Profile
Re: STK Chips....why there´s nothing about them here?
« Reply #12 on: February 02, 2009, 08:12:48 AM »
Hola DSMNOISEM. Lo que veo con los STK es que aparentemente son hechos "a pedido" para los grandes fabricantes orientales, en cantidades de 100K a 1M, según sus especificaciones, las que, obvio, son Hi Fi, stereo, etc., y lo que aparece en el mercado debe ser un "sobrante de producción". El problema para un constructor aficionado como nosotros, es que debemos comprar "lo que hay", y eso varía mucho. En cambio, el LM3876 original, fue luego reemplazado por el LM3886, manteniendo el pinout (bueno, 1 pin quedó sin usar), lo que permite, si diseñás una plaqueta, que sea útil para muchos,durante  mucho tiempo. Fijate lo que pasó con el TDA1514, usado por Marshall y otros: hoy cuesta muchísimo conseguirlo; con un STK eso habría pasado muchas veces. En cambio, los TDA20xx son abundantes y todos los mono tienen el mismo pinout. Los STK son típicos de Sansui, Pioneer, etc. y creo que alguien como Yamaha los usó, pero si hoy te aparece uno quemado, tenés que tirarlo (o, con suerte, adaptarlo). Saludos desde Buenos Aires.

RDV

  • RIP - 2/5/10
  • Elite
  • ****
  • Posts: 291
  • Chip Points: 419
    • View Profile
    • Fatboy Effects
Re: STK Chips....why there´s nothing about them here?
« Reply #13 on: February 02, 2009, 03:56:56 PM »
For those who don't understand the previous post.

Hello DSMNOISEM. What I see is with STK that are apparently made "on demand" for large eastern manufacturers, in quantities of 100K to 1M, depending on their specifications, which, obviously, are hi-fi, stereo, etc.. And what appears in the market must be an "excess production". The problem for an amateur builder like us, we must buy "what is", and this varies widely. In contrast, the LM3876 original, was later replaced by the LM3886, keeping the pinout (well, 1 pin was not used), allowing, if a chip design that is useful for many, for a long time. Look what happened with the TDA1514, used by Marshall and others: it costs a lot now it works with an STK that had happened many times. In contrast, abundant TDA20xx mono and all have the same pinout. The STK is typical of Sansui, Pioneer, etc. and I think someone used them as Yamaha, but if today you get a burn, you have to throw (or, ideally, fit). Saludos desde Buenos Aires.

J M Fahey

  • SSGuitar Global Mod
  • Legendary
  • ****
  • Posts: 4142
  • Chip Points: 429
    • View Profile
Re: STK Chips....why there´s nothing about them here?
« Reply #14 on: February 04, 2009, 07:52:52 AM »
Hi RDV. Thanks, excellent translation. I had second thoughts about my post, but since it was adressed specifically to my Chilean neighbour, and he already was referring us to a Spanish written page, I just wrote it in Spanish. I´ve already seen that 99,9% of projects here refer to the same 2 or 3 chips: LM3886, TDA20xx and specially the ubiquitous and very easy to use LM386, which is a good idea. I just wanted to make clear to our friend that it was somewhat unlikely that someone else would "debug" a new PCB design for a chip not easily available.
Thanks.