40 yrs old philips ag9016 se flea-power ?

[Peng]

I've purchased this 40years old philips AG9016 se stereo amp with 2xECC83 and 2xEL95. 2x2watts into 5 Ohms !
Just to see/hear what this talk about the 'magic' of tubes is all about.
I got home with the amp and connected it to my speakers (pied pipers) and cd player (philips cd850 mkII).
No big expectations. What can you expect from 2 watts (?). But I was completely amazed ! The small amp filled my livingroom of 34m2 completely with music (volume at 3/4) and it sounded excellent (my speakers must be quite sensitive!)! There really is something to this 'tube-magic' .....
No hum , no cracks - this amp is really silent.
The AG9016 has treble, bass, balance and volume control (and a loudness capacitor on the volumepot).
Imputs for ceramic pickup, tape and radio.

Although it already sounds great, I am convinced there are things that can be done to make it even sound better (everything except for the tubes, is 40 years old !).

Get rid of tone control, loudness cap?
New caps, resistors (which ones?)
Change input sensitivity?

I am a newbie in these tubes, so any help would be highly appreciated!
Schematic can be found here (i tried to attach it but it is too big) http://pjeantaud.free.fr/schemas/ag9016.zip (i hope he does not mind)
If there is anyone with more documentation, please feel free to send me a copy by email .....

[Joel]

2 watts isn't really "flea power", to me at least. That's +15dB of headroom above my normal listening levels.

Flea power is a #31 single-ended.

[bournville]

...Well, your amp was designed for higher impedence inputs than your CD player, so you could loose the input network circuits and apply the signal directly across the volume controls, which you could drop to a lower value (say 100k) and loose the compensation network...

You could also experiment in increasing the negative feedback from the output transformer, reducing the values from 1.5k. However, I suspect that to make any real difference to the frequency response you'd have to look at the output trannies, and so it depends on what you want to spend on a 40 year old amp giving a couple of watts per channel.

[jean-paul]

Penq, this very good sounding amp was described in 2 issues of Audio&Techniek magazine several years ago. I have those issues. If I have the time I'll scan them and mail them if you leave your mailadress or if you contact me via the moderators.

They modified it twice and the results were pretty good. I had two AG9016's and I sure remember drilling holes for cinch connectors ! Very tough steel with a lot of carbon in it.

You'll have to change the high voltage caps anyhow. You'll be surprised what a difference that makes, they're definitely worn out after 40 years

[Netlist]

While you’re at it, take out (and replace) those black capacitors
as well. (Those that melt instantly when you touch them with a soldering iron )

/Hugo - 20.000cm

[jean-paul]

Better wait for the modified schematics before replacing anything

What's that with the 20 cm Hugo ? Are those caps that long ?

[Peng]

Bournville,

Thanks for the input. As matter a fact the inputsignal are already directly applied to the volume controls. I have removed the loudness circuit (cap and resistor). I will certainly look into the other options. For now it seems to be a good thing to check the item that was published in AUDIO&TECHNIEK as Jean-Paul mentioned,
therefore,

Jean Paul,
This seems to be exactly what i'm looking for to get me going!
Indeed the quality of the housing is outstanding. Putting in cinch however really has to be done. Looking forward to this

If you find time to scan......? pthieme@home.nl
(would be highly appreciated !)


Netlist,
Any particular type/make I should use ?

BTW somebody was so nice to mail me the scans of the original documentation of 1963 !
Nice people on this forum.

Oh Joel,
What do you mean with #31 ?


Greetz
Peng

[fdegrove]

Hi,

What's that with the 20 cm Hugo ? Are those caps that long ?

Just a case of wishful thinking?

Jean-Paul,

Seems you've been one of those A&T readers too?
I must have those modded circuits too.
One thing I can say with absolute certainty: in those days Philips really meant business when they said: "Let's make things better".

Nowadays I'm not too sure about that claim,

[fdegrove]

Hi,

What do you mean with #31 ?

If Joel doesn't mind...I know he will.

RCA type 31 or 231 is just a tiny power triode from the 1930s.
Delivering a fraction of a Watt if you're lucky and running downhill.

[Netlist]

Originally posted by jean-paul

What's that with the 20 cm Hugo ? Are those caps that long ?

I was referring to the very old caps that were labelled in cm instead of µF.
Did you ever see them?

/Hugo