"PINNACLE AB200" - Class AB DIY Amplifier with thermal track transistors NJL3281D & NJL1302D

[sadik]

Yes this Amplifier is too Good for such a high power rating and as I said even at higher volume the sound is clean which points out the low distortion figure is doing its job very well. Only 5 PCB's are manufactured and 3 PCB's are built, 2 PCB's are in spare. So as for now those spare PCB's are not available for sale.

The Heat-sinks were purchased form Akash Enterprise Pune.

For custom toroidal Torotrans Pune

 

[sadik]

A Major Update. (Changing EI core transformer with R-Core transformer)

Let me be clear first related to the sound quality. It is still the second best sounding amplifier i had made.

Now I am sharing my observations of 2 weeks of running and a long run session (Continuous 10+hours)

1. Noticed some mechanical vibrations of EI transformer which was noticeable on lower volume.
2. The transformer was getting a hot when played at loud volumes.
3. After Playing the amplifier for 8+ hours, the mechanical noise was increasing and it was noticeable at listening position.
4. This noise can even be heard from speakers.

Solution.
Replaced the EI Transformer (600VA) with R Core (750 VA - Shielded)

All the above stated problems just vanished in air. I have been playing the amp for more than 10 hours now, there is no mechanical vibration nor any kind of noise from speakers. The R Core transformer is also cool, its not getting hot.

I think i had gained more power, may be because of bigger rating of transformer. The sound character is same as it was earlier. Below are some Photos.

R Core Shielded Transformer made by Shilchar

Enjoying the music now.

Sadik

 

[sadik]

Sadik, what was the make of EI core transformer that came with amp ? Another higher rated EI core transformer would have done the job too.

The EI was also from Shilchar. The culprit may be the magnetic flux of the EI core (just googled)

 

[sadik]

Surprising...... Shilchar made transformer...... supposed to be very high quality.

Out of enclosure the transformer is working fine. No noise at all. What I figured out right now is the height of enclosure. The transformer height is around 100 mm & enclosure internal height is around 103 mm this 3 mm gap can be the culprit causing the enclosure to vibrate.

I will use this EI core in some another built. with a heighted enclosure.

Sadik

 

[sachu888]

That R core is massive, Sadik bhai.

Regards
Sachin

 

[sadik]

That R core is massive, Sadik bhai.

Regards
Sachin

Yes it is really big.