ovation sx amplifier

[Wolletje]

I incorporated your feedback from your build into the latest document bambadoo - should be up to date.

Wolletje, V1.0 boards are quite old - there were a few component value changes IIRC after that. Where did you get you boards from?

Here is the link to the sx-Amp article Ovation sx-Amplifier: A High Performance 15 W Class A Current Feedback Amplifier

If you have questions, just email me.

Hi,
Thanks for the information.
Mabey there will be more from this diyaudio.
I hope hifisonic can help me also with this project with information.
I left a message there.
With regards Frits

 

[bambadoo]

Bonsai = hifisonix
You are in the best of hands Skilful and helpful.

 

[Bonsai]

 

[Wolletje]

Hi,
I have a question about Q3 and the solution mentioned by bambadoo. I saw a picture with a short from leg basis Q3 to R20 and a photo with a connection to R21. I do not understand witch of both is the solution or is the R20 with the 2.2/2.4K the solution for the Q3?
The C2 SMD on the amp circuit. This one not solder?
With regards, Frits

 

[Bonsai]

Wolletjr,
Please send me a picture of your PCB.

 

[Wolletje]

SX amplifier 2012 V10 version pictures

Wolletjr,
Please send me a picture of your PCB.

 

[Bonsai]

Ok - I will answer you later today or on Thursday - it’s Chrismas where I am

 

[Wolletje]

Thanks and happy christmas!

 

[Wolletje]

Hi,
All the components for the sx amp are arrived a time ago and I like to start soldering but I am very very unsure about this last point and I need a solution for this point. I did not see a solution for this question yet.
There is a picture I got from Bambadoo e-mail, there is a jumper wire from Q3 (BC547C) to resistor R20 (R21 ?). Do I solder this jumper? Instead BC547C I use BC550C. But I suppose that's no big difference for this point.
I am happy with any help in making this amplifier. Thanks, Frits

 

[Wolletje]

Hi Andrew,
I have soldered the most parts on the amplifier circuit but there is one resistor I do not understand R9:.... 3.3R 2W on the circuit and in the BOM list 3.3R 0.5W . Can I use the 2W or the 0.5W? This is a flame resistant resistor?
With regards Frits

 

[thimios]

Hi Andrew,
I have soldered the most parts on the amplifier circuit but there is one resistor I do not understand R9:.... 3.3R 2W on the circuit and in the BOM list 3.3R 0.5W . Can I use the 2W or the 0.5W? This is a flame resistant resistor?
With regards Frits

Use 2W resistor in R9 position.

 

[Bonsai]

Yes Thimios is correct.

 

[Wolletje]

Hi,
Thanks all, very helpful

Another questions:

1) The fuses 5A on the amp board? I cannot find if they must be slow (T) or fast (F) fuses?

2a) On mine version PSU are two rectifiers. Should I provide them with a cooling radiator?
2b) And I have to solder a 10nF 100V capacitor(s?) on the bottom of the PSU. I think from J3 (GND) to J14/J4 (OVC) but that is a great distance (50mm) on mine board. Is this right or is there another solution. I can extend the legs of the capacitors.
With regards, Frits

 

[Bonsai]

Hello Fritz

1. The fuses must be T types

2. PCB Rectifiers: Only D4 needs a Heatsink.

3. Please leave C4, C5, C7 and C8 off - no need to fit them.

 

[Wolletje]

Hi Bonzai,
Thanks again for this
Ok clear!
I solder already C4......C8 because the advice was to do this first those little SMD.
I go desolder them, was a good practice, never solder SMD. Great fun with shaking hands....