STK407-050 module alive and kicking

Tekko

Banned
2005-01-01 3:33 pm
Hello diyers!

This is actually not a chip amp, inside these modules there is a small circuit board with SMT components, transistors, resistors and caps. This will make Franz G happy to see. Tho i feel bad that i have been unable to send him his 10 euro for the shipping :(

Here she is in test bench and going strong :)
[IMGDEAD]http://user.faktiskt.se/Tekko_Tubeamp/STK407-050/The%20amp%20module.JPG[/IMGDEAD]
[IMGDEAD]http://user.faktiskt.se/Tekko_Tubeamp/STK407-050/The%20test%20amp.JPG[/IMGDEAD]

And the schemo of the test setup:
[IMGDEAD]http://user.faktiskt.se/Tekko_Tubeamp/STK407-050/STK407-050%20test%20circuit.JPG[/IMGDEAD]

To Franz: I´ll get your payment sent as soon as i am on the bank i´ll ask for a exchange to euros.
 

Tekko

Banned
2005-01-01 3:33 pm
These modules sounds really darn good. I changed the module in a amp i had that was a 4132II which had 1%THD to a 5151V that has a THD of 0.08% and slightly higher power, tho the transformer cant cope with that 10w higher power but i´ll never be at that level anyway.
 

Tekko

Banned
2005-01-01 3:33 pm
The real thing

NOW i have built the real thing on a board, it took about seven hours to do. I noticed i forgot the zobel link when i hooked it up so i have to solder those on tomorrow.

Heres some pics:
[IMGDEAD]http://user.faktiskt.se/Tekko_Tubeamp/STK407-050/30%20watt%20amp/2x30w%20amp.JPG[/IMGDEAD]
[IMGDEAD]http://user.faktiskt.se/Tekko_Tubeamp/STK407-050/30%20watt%20amp/all%20components%20needed.JPG[/IMGDEAD]
[IMGDEAD]http://user.faktiskt.se/Tekko_Tubeamp/STK407-050/30%20watt%20amp/Massive%20starground.JPG[/IMGDEAD]

Here the baby is plugged in and working like a charm:
[IMGDEAD]http://user.faktiskt.se/Tekko_Tubeamp/STK407-050/30%20watt%20amp/Plugged%20in.JPG[/IMGDEAD]
 

Tekko

Banned
2005-01-01 3:33 pm
If the pics arent working, try right click and click on show picture.

This amp sounds really good and doesent even get warm, tho the transformer i use (from a home cinema receiver) gets honking hot:hot: Its a 450-500VA unit and its set for 240vac in.

A pic of one of these modules inside for those who is interested:
[IMGDEAD]http://user.faktiskt.se/Tekko_Tubeamp/STK407-050/en%20modul%20inuti.JPG[/IMGDEAD]
 

Tekko

Banned
2005-01-01 3:33 pm
Then the server is prolly programmed not to allow linking to forums other than in sweden or norway, some ppl in denmark has problems as well. I have put the pics on another server, here they come:

The schematic:
[IMGDEAD]http://hififorum.knaak.dk/Tekko/STK407-050/STK407-050%20test%20circuit.JPG[/IMGDEAD]

The module:
[IMGDEAD]http://hififorum.knaak.dk/Tekko/STK407-050/The%20amp%20module.JPG[/IMGDEAD]

A module inside:
[IMGDEAD]http://hififorum.knaak.dk/Tekko/STK407-050/en%20modul%20inuti.JPG[/IMGDEAD]

The amplifier in testbench:
[IMGDEAD]http://hififorum.knaak.dk/Tekko/STK407-050/30%20watt%20amp/2x30w%20amp.JPG[/IMGDEAD]
[IMGDEAD]http://hififorum.knaak.dk/Tekko/STK407-050/30%20watt%20amp/Massive%20starground.JPG[/IMGDEAD]
[IMGDEAD]http://hififorum.knaak.dk/Tekko/STK407-050/30%20watt%20amp/all%20components%20needed.JPG[/IMGDEAD]
[IMGDEAD]http://hififorum.knaak.dk/Tekko/STK407-050/30%20watt%20amp/Plugged%20in.JPG[/IMGDEAD]

The amp beeing mointed in the chassis:
[IMGDEAD]http://hififorum.knaak.dk/Tekko/STK407-050/30%20watt%20amp/chassis%20front.JPG[/IMGDEAD]
[IMGDEAD]http://hififorum.knaak.dk/Tekko/STK407-050/30%20watt%20amp/chassis%20ugly%20back.JPG[/IMGDEAD]
[IMGDEAD]http://hififorum.knaak.dk/Tekko/STK407-050/30%20watt%20amp/finished%20transformer%20side.JPG[/IMGDEAD]

Notice the starground:
[IMGDEAD]http://hififorum.knaak.dk/Tekko/STK407-050/30%20watt%20amp/finished%20amp%20side.JPG[/IMGDEAD]

The amps backside, very ugly but as i only have dull junk tools that is the best i can do:
[IMGDEAD]http://hififorum.knaak.dk/Tekko/STK407-050/30%20watt%20amp/input%20and%20speaker%20connectors.JPG[/IMGDEAD]

Heres the amp is totally completed, tho i have changed the volume knob to a bigger one:
[IMGDEAD]http://hififorum.knaak.dk/Tekko/STK407-050/30%20watt%20amp/complete.JPG[/IMGDEAD]

And here it is in its final place:
[IMGDEAD]http://hififorum.knaak.dk/Tekko/stereon/new/up%20to%20date/Philips%20vs%20Tekko%20Audio%20Products.JPG[/IMGDEAD]

Due to old **** tools and a chassis that another n00b destroyed this is the best i can do. Tell me what you think, ugly or ok looking.
 

steenoe

Member
2004-03-23 10:43 am
i never mailed him the postage money either.
You guy's better shape up on that! Otherwise the goodwill, might drop! That would be a bad thing for this community, wouldn't it:rolleyes: Com'on, Franz is offering these thing for you, only for the shipping cost! Franz, is always contributing, and happy to help youngsters:bawling: Send him, what you owe him.
Sorry to make this rather harsh comment :bawling:

Steen:hot:
 
How inportant is the voltage rating on a cap ? I noticed im exceeding the max of 35v om the preamp caps on this amp with one volt, they dont get hot but will it degrade them over time ?

It is not safe practices to exeed the max voltage and does shorten life of the whole circuit.

Is your multimeter exactly?

Use at least secondary fuses melting in case of a caps shortage.

Regards
Franz

P.S.
I like to see that you made an obviously good sounding amp out of this modules :)

P.P.S.
Did you see the "sheer horror" :clown: I made with my dremel, to remove a PMD-100 chip?

http://www.diyaudio.com/forums/showthread.php?postid=683495#post683495
 

Tekko

Banned
2005-01-01 3:33 pm
The caps overvolting is behind 100 ohm resistors, its for the preamp part so if they fo poof the resistors (1/4 w) will burn out like fuses. Could overvolting cap let more ripple in than one that have like 10 volts left before its max voltage is reached ?

What would the difference be with lower gain except that i need a higher input signal for the same volume output ?

PS: i have done that too to get chips i wanned off the boards;)

PPS: XELB, which one do you have ?
 
Tekko: When exceeding the spec'ed voltage there is a big difference what happens to a cheap capacitor and a good quality capacitor. It appears your caps are Marcon, which is a good solid brand. In this case your capacitor will lose some of it's marked uF value over time, when exposed to slight overvoltage. It will not blow up, and if your circuit tolerates 5000 uF instead of the marked 6800 uF, you will not be in trouble, or severely shorten the life of your amplifier.

However never exceed the surge voltage, because then any capacitor might blow up. For a 63V marked cap the typical surge voltage is 79V.

And never use a cheap ping pong capacitor anywhere near it's rated voltage, because those might just blow up after a couple of months. Max 50V for a 63V capacitor.

Anyway really one of the nicer versions of a 'chip amp'. ;) Congratulations....