Philips AH578 shematic

donr

Member
2006-10-12 2:40 pm
Hi everyone
New member here. I own an old Philips Laboratory series AH578 power amp. I have been desperately trying to find a service manual or at least the schematic for this amp to no avail. Even Philips customer support can't help me. I stumbled across one post by EchoWars who said he had the schematic for this amp. Unfortunately, being a new member, I can not pm him.
Would anyone have a copy of this that they would be willing to scan and email me? I am the original owner of this amp( purchased in 1978) and it has sentimental value to me plus I think it is a great amp. I would like to be able to fix it even though I am but a hobbiest. Thank's
Don
 
no philips

machine can ever be a "greate amp "...sorry to say that ....its a personal opinion ......

i have i friend that previously like 15 years ago worked for the philips greece ....i will drop him a mail and let u know ....

this guy was audio specialist he had 4 eyes and three hands ....this is what normally takes tro repair a philips device ....


( pls dont missunderstand me ..... i hate philips audio and i try to make a joke about it )

give me a couple of days and i ll let you know ..... i know this guy kept schematics for his own plesure
 
AH578 PHILIPS POWER AMPLIFIER

I just happened onto this forum and saw that DON was seeking a service manual for the AH578 Philip Amp... I have a mint condition service manual and owners manual.

Also I have two amplifiers, one AH673 Tuner and one AH572 Pre-Amp if anyone is interested with the requisite owners manuals.
 
I would be happy to have this manual and schematic

Please, upload it to my mail box:

[email protected]

Or show me the way to have it... were to find.

The adress informed is not working....i have tried the mfbfreaks and could not make contact with that adress.

Phillips belongs to my youth.... the sound is important in my life... even considering it is not "that special".

regards,

Carlos
 
Some Philips models are nice

here you have, a not too much old, schematic diagram.

The missed parts depends you source impedance and your own decisions about...the chip is TL081 or other op amplifier...the feedback network must obbey op amp datasheet.

regards,

Carlos
 

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Hello,
I designed the AH578 when I was an electronics design engineer working for Magnavox/Philips in Fort Wayne, Indiana. While I discarded my schematics and design information, I may be able to answer some questions about the AH578. I can be e-mailed at [email protected].
Regards, Earl Rapp

You are my idol. I feel AH578 and the PL300 has the same structure. Was going to copy AH578. I will not English, can only be translated by google.
 

tunedguy57

Member
2009-01-18 12:19 pm
Hello,
I designed the AH578 when I was an electronics design engineer working for Magnavox/Philips in Fort Wayne, Indiana. While I discarded my schematics and design information, I may be able to answer some questions about the AH578. I can be e-mailed at [email protected].
Regards, Earl Rapp

wow! It's a honour! Please tell us everything you have pleasure to say...I wrote you a mail, and will wait for your answer.

regards
tunedguy57
 

Tandberg

Member
2009-12-09 1:12 pm
@ EARL Rapp!

Please can you help us with the coded Partnumbers of all the transistors in the AH578.
I only know the input IC is a CA3100S similar to the new HA-2525 - 20MHz, High Slew Rate OP Amp and the output stage trans. 355NI are todays ON Semi MJ15024.
Thank you very much
Tandberg
 

Tandberg

Member
2009-12-09 1:12 pm
Hello!
Have bought an AH578, the seller told me tghat one channel has a 50Hz distortion,
now when I testet the unit, it is not a 50Hz distortion by elektronic parts, it is simply a mechanic sound from the main transformer. Knows anybody more about this problem.
Before opening: Is the transformer totally glued with resin, or is there a possibility to tighten the screws, to overcome the sound of "magnetostriction".

Thanx

Tandberg
 
PHILIPS

machine can ever be a "greate amp "...sorry to say that ....its a personal opinion ......

i have i friend that previously like 15 years ago worked for the philips greece ....i will drop him a mail and let u know ....

this guy was audio specialist he had 4 eyes and three hands ....this is what normally takes tro repair a philips device ....


( pls dont missunderstand me ..... i hate philips audio and i try to make a joke about it )

give me a couple of days and i ll let you know ..... i know this guy kept schematics for his own plesure

Hello, what do you have against PHILIPS?? Together with Sony they are the worlds leading companies concerning sound and vision etc..
Thanks to PHILIPS you have been able to enjoy colour TV( 1967), Videorecorder ( 1967!), Compact Cassette (1963!), the predecessor of the DVD, Laserdisc ( 1983), CD ( 1982), Motional Feedback Louspeakers , HiFi/ consumer- electronics ( > 1967) and so on and so on. And since the EISA rewards started, PHILIPS many a time won for the best product and still regularly does. As you notice, I DO NOT hate PHILIPS but I am very proud of their 120 years of history, and for that accomplishment they may call themselves "Royal PHILIPS N.V." since they celibrated their 100th birthday. I have a huge collection of PHILIPS HiFi and you will be astounded about the quality that was made although not everything was perfect: not only at PHILIPS but with all manufacturers. Not even a Rolls- Royce is perfect!:scratch:
I still use the PHILIPS Lab-set dating from 1978 ( AH573,AH572,AH578,N5741,AF829,N4520,CD303,N6330 electrostatic headphones and 4x FB825 Conductor series loudspeakers. After all these years it is very, very hard to beat this set, I can assure you:drink:. For what repairing is concerned: some- one here referred to www.mfbfreaks.nl and the coincidence is that their repair shop is 5 kilometers from my home at Krimpen aan de IJssel( Netherlands) near Rotterdam and I visit him often, just for fun. The man is a wizard and knows PHILIPS by heart. The vintage equipement isn't difficult to repair at all! Just the very first series MFB speakers (1973)are tricky for there was a small designflaw in them. But he knows how to handle them and if needed, repair them. But you'll be surprised how many MFB speakers are still in use and working flawlessly still. Quite a wonder for they're quite complex but very reliable.
No....I DO know several friends and aquaintences who one(d) a Denon, Harman Kardon or Quad who could "throw away" their amps after just 6-8 years for their amps where broken and beyond repair ( way too expensive) and the usual Audio you buy today is ****. One chip busted> byebye to the machine.
So please be a bit more neutral about PHILIPS.......
With a cashflow of about 50 Billion Euros every year (!!) one must respect this company...At home watching a PHILIPS Flatscreen, the next morning in a CT- Scanner in hospital......from PHILIPS..and no jokes .....
All the best for Greece and for you too, of course:drink:
 

Kidomaha

Member
2012-11-04 2:11 am
Rescued an AH572

Hi all. I just joined. Today, I rescued an AH572 from an E-Recycle bin. The tuner was there too but I really had no idea that these pieces were so sought after and wonderful. (I will make an effort to go back and rescue the tuner. I really hope the amp is there too). I just read the post from Earl Rapp. Very cool. I'm in Fort Wayne, IN too. Amazingly, the AH572 I rescued appears to be in perfect working order. All the lights are functional, knobs work etc... Thanks for the thread all.

Kerry Hultquist
 
I am never to be surprised when the word Philips appeares in any fora where HiFi is the central element.
And all the haters of that brand.
I have had far more pleasant HiFi-experiences with Philips than any other brands.
Strange?
Not at all in my opinion.
The most fun I ever had were when all the HiFi-world built good CD-players.
Everyone of them stated they had built their CD-tray and pickup themselves, but barely any High-End manufacturer managed to hide the fact that they often had a complete Philips transport inside.
¨Philips is plastic" is a common statement in my country.
And you can never have good HiFi when plastic is involved.
I still own the very first recordplayer I bought for my own money.
All my friends laught at me tellein me how much trouble I would get when buying such plastic-device. They all bought Direct Drive turntables, and they all were sure i never would be able to experience good HiFi on a turntable that was:
Fully automatic
Belt driven
Electronically operated with touch-controls.
A chassis built of plastic.

Not any of my friends own their first turntable today. I do.:D

My 22GF222 Electronic with GA412 IIISST pickup is still delivering the goods.
Other early Philips HiFi equipment I bought the next years contains a CD-player (CD-150) the complate HiFi-rack 455 (Tuner, Amplifier and autoreverse cassette deck)
None of this is High-End, but do they deliver good sound?
Yes they do.

The AH578 was a tremendous amplifier, and if Philips had sent it out under any other name, they would have sold ten times what they actually did.
But you know, Philips? Plastic can't be HiFi..... :rolleyes:

Agree with Philips578 here: Philips is perhaps THE greatest contributor to get GOOD audioproducts out to the people.
A lot of patents originated from them, a lot other they bought.

But hate Philips? I just ask: WHY?
 

thoglette

Member
2008-12-20 5:59 am
But hate Philips? I just ask: WHY?

Mostly because most people only see the "low end"

BTW - data sheets at
http://www.mfbfreaks.nl/pdf/amps/578/22ah578.pdf

Also dead unit for sale in .au (west coast) for $45AUD (c. $30 USD, 25euro)
Philips Power Amplifier 578 (Valve Amp) | Other Books, Music & Games | Gumtree Australia Vincent Area - Mount Hawthorn | 1074664515

Interestingly the output is quasicomplimentary and requires beta matched parts. Not for the faint hearted!


Another thread here Wim Schilperoort found replacements for most devices

@earlrapp - did you ever get around to answering Tandbergs query on what the actual output devices where? 355N1
 
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