STK459 replacement - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 29th November 2011, 01:40 PM   #1
diyAudio Member
 
Join Date: Jan 2008
Send a message via MSN to Lumbermatt
Default STK459 replacement

Hi all,

I actually try to repair an Onkyo TX15 Amp/FM receiver which is based on an STK459 chip amplifier. The STK459 doesn’t work anymore, I found some replacement parts. Surprisingly, some online resellers seem to have some STK459 in shop for approx. 25-30€.

Since I’m repairing that amp more for fun and challenge than something else, I was thinking about using another power amp which may have some better characteristics than this more than 10-years old IC.

What in your mind could be a replacement IC that would provide a better sound than the STK459 ?

Thanks in advance,

Last edited by Lumbermatt; 29th November 2011 at 01:44 PM.
  Reply With Quote
Old 2nd December 2011, 03:59 PM   #2
Jay is offline Jay  Indonesia
diyAudio Member
 
Join Date: Feb 2003
Location: Jakarta
STK459 is a good one. Don't look from the age, but Sanyo chips have "classes". Unfortunately it is just 15W.

With original power of only 15W, the transformer capacity will also be that small. You can build a new amp to be attached on the old heatsink. Find IC that requires small heatsink and can be fed with the same supply (around +/-21V)

TDA2030 is good but the original power supply will probably be too high (18V is max here).

LM1875 will give around 18W @ 8Ohm-21V. But may be the heatsink will get very hot at full power.

A discrete amplifier with TIP31/32 will be better, if you know how to do it. You will need a breadboard pcb to be attached on the heatsink. Just search the forum for small BJT amplifier. Or may be you can find such amplifier module locally. Here, the cost will be less than $5, with "fake" components.
  Reply With Quote
Old 2nd December 2011, 04:20 PM   #3
Jay is offline Jay  Indonesia
diyAudio Member
 
Join Date: Feb 2003
Location: Jakarta
BTW, overture series from National is good. LM3875 is rated max 56W, LM4766/LM4765 is rated max 30W. With 21V supply they will give around 20W. Cheaper than the STK.
  Reply With Quote
Old 5th December 2011, 05:19 PM   #4
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
STK 457, 459, 460, 461, 463 are all pin compatible.
Fake "OEM" STK 465 is also pin compatible but the optimal support circuit is different on the New/current production item, so that's not an exact replacement.
Cheaper modern chips aren't necessarily better, nor more powerful.
What is an STK chip? Its a real discrete solid state amplifier jam packed into a little black box. Nearest match is a discrete amplifier, not a chip.

Want better sound than STK459? STK460 on regulated power.

When also within a circuit optimized for it, including bass treble controls, I don't think that there's any other chip that an beat it unless you cable bypass all of the controls except for the source selector. In this case, a refit to a modern chip is like vandalism. And, without completely bypassing the tone section, a refit/modernization is pointless since that would only degrade performance, as in screaming mids, weird tone, and probably lots of clipping. Instead of terrible noise and/or cut out features, I'd rather use STK 459/460 or 461/463 for restorations.

Wattage output? In the past, they measured at 0.01% or better figures. Actually if you crank that thing up to modern measuring figures, its puts out more than 15 watts. For production examples, its more like 27w (only 3 decibels less than a 55w amplifier). Some odd 34 years ago, customers bought audio amplifiers by favorable distortion figures and the easiest way to publish such figures is to turn the volume control to about half, then advertising both less wattage and less distortion. Today's practice is the opposite.

Usually, the STK459 was cherry picked for manufacturers, a non-standard model, with better specs and a higher voltage tolerance. Check your power supply voltage!

The six chips in that family have only 2 designs.
457/459/460 for pair of 18 to 24vdc rails
461/463/465 for pair of 24 to 30vdc rails

There are alternatives to restore original performance while also using a modern chip, but, you're looking at a fairly big mess that certainly doesn't cost less than simply using the correct part.
  Reply With Quote
Old 11th December 2011, 05:52 PM   #5
mjf is offline mjf  Austria
diyAudio Member
 
Join Date: Jan 2009
Location: Austria
hello.
i have an old sanyo dca205 integrated amp, one of my "tweaker's objects".
one channel of the stk461 inside was dead,so i substituted it with the cheaper stk459 (i bought it from a wellknown german electronic seller)........psu volts are a little bit higher than recommended,but it works without problems.
i recapped the amp,all electrolytics were changed to new ones,
and after that the big (cheap) ceramic caps with plastic caps (mkt and so on.).
may say the amp sounds much better than i thought it could be.......

Last edited by mjf; 11th December 2011 at 05:55 PM.
  Reply With Quote
Old 12th December 2011, 01:52 PM   #6
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
That is okay if it is running 8 ohm speakers and if the amplifier has mains fuses. Even so, it is running a slight overrun condition and I would expect it to fail, in approximately 40 years. That lifespan would be for a "pull" or a NOS replacement part for an amplifier brand.
However, an STK generic or an authentic part that wasn't the higher spec for big name manufacturers may have a much shorter lifespan.

There are 2 or 3 different STK459. . .

The best of these were made for Technics, or Sony, or some other big name that have higher/better spec because the manufacturer required it and because the part was especially made to the requirements of the amplifier manufacturer. Today it is found as a "pull"

The worst is the current production "OEM" fake STK465 with the label re-printed to STK459 in order to attract a greater amount of customers. Such a re-labeling is typical of generic parts.

In-between the two extremes is the normal grade STK459. This one matches the datasheet. It was sold to hobbyists and parts vendors.

Last edited by danielwritesbac; 12th December 2011 at 02:05 PM.
  Reply With Quote
Old 7th March 2012, 08:44 AM   #7
mlr is offline mlr  Philippines
diyAudio Member
 
Join Date: Feb 2012
i have an old AKAI amplifier with an STK461 chip... the chip is not working anymore and the fuse keeps on blowing out!... dnt know why... and i thought of replacing the chip with STK465. can it be possible?
  Reply With Quote
Old 7th March 2012, 08:48 AM   #8
mlr is offline mlr  Philippines
diyAudio Member
 
Join Date: Feb 2012
i just want to repair my old amp and see if i can restore it and maybe perhaps boost its power output by replacing the STK461 to STK465.. thanks for the help!
  Reply With Quote
Old 7th March 2012, 07:47 PM   #9
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
Quote:
Originally Posted by mlr View Post
i have an old AKAI amplifier with an STK461 chip... the chip is not working anymore and the fuse keeps on blowing out!... don't know why... and I thought of replacing the chip with STK465. can it be possible?
Those are pin compatible so you can replace STK461 with STK465 if you like.

However, there are many possible causes of fuse blowing, for example, bad caps, failed dc detector circuit, loose soldering, burnt resistor, worn relay, etc. . .
  Reply With Quote
Old 16th March 2012, 12:43 PM   #10
mlr is offline mlr  Philippines
diyAudio Member
 
Join Date: Feb 2012
thanks so much for that info... i have already fixed the "blown fuse" problem". one of the caps is leaked and loosen... haven't yet bought the STK465 but i there are still available. i replaced my 2 6200uf/35v main caps for a 10,000uf/65v caps. are that ok? hoping to give out a more steady charge into the chip.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
help with replacement tweeter replacement - KLH twenty three indianajo Multi-Way 2 15th February 2010 12:54 AM
BC517 replacement msm677 Car Audio 7 12th July 2007 03:02 PM
How to use STK459 in bridge mode tridibesh Solid State 0 4th June 2005 07:40 AM
Replacement of a CDM1 Rolly Digital Source 0 18th October 2004 08:12 AM
Stk459 / Stk463 nbcd Chip Amps 4 15th September 2004 11:51 AM


New To Site? Need Help?

All times are GMT. The time now is 11:21 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2