Altering AMP4 Kit -PIO Caps, Coils, Atten., Batts.
My last post about this was a bit sloppy and inaccurate, so I've organised it into a new one.
After having a Sonic T amp for a fair few months, and being very impressed with its performance, I looked into making myself another ‘class t’ amp. Coincidentally, my T-amp seemed to develop an irreparable fault. After only a minute or two of standard use there would be a huge noise build up through one of the channels until it reached an unbearable level; the chip got very hot too, but cooling it seemed to make little difference.
Anyway, I’ve recently bought an amp4 kit from www.41hz.com I've been looking over the spec, looking at other TK2050 amps, and listening to other people's ideas as to how you can 'upgrade' this kit, without wasting money. As will become very obvious by the end of this thread, after reading the <span style="text-decoration: underline;">6</span>moon's review of the Red Wine Audio Signature 30, I’m aiming to try and replicate that amp’s performance as much as my budget will allow. It uses essentially the same tripath chip.
There are a few areas I’ve been considering:
Coils
I’ve got a clear choice between toriodial or air core:
<span style="font-weight: bold;">Air core</span> – Many DIY people I’ve spoken to have said they believe these to have ‘a smoother operation.’ I’ve been pointed in the direction of these from autocostruire.
<span style="font-weight: bold;">Toroidal</span> – These are what come as standard with the 41hz kit and also supposedly what Vinnie uses in the Signature 30. According to him these are ‘favored over air-core inductors for better bass definition, speed, dynamics, and lower noise’. However, I haven’t looked out of <span style="font-weight: bold;">ferrite</span> cores to other cores, such as <span style="font-weight: bold;">MMP</span>.
Capactiors (input filter)
It seems the general opinion is that paper in oil capacitors are the way to go. As for what value – the 41hz kit comes with 1uF and 3.3uF, but after discussions with Vinnie, he said he used a value of 2.2uF, which is a compromise between the two, so I think I shall follow suit. However, back to what type of capacitor:
<span style="font-weight: bold;">Jenson:</span>
<span style="font-weight: bold;">Copper Foil</span> 2.2uF 100V - $60.95 – <span style="font-style: italic;">Very</span> pricey, but exactly what the Sig 30 uses. Supposedly legendary.
<span style="font-weight: bold;">Mundorf:</span>
<span style="font-weight: bold;">Silver in Oil</span> 2.2uF 1000V - $43.90 – Not cheap, but considerably less than the Jensens. Some people who have made their own amps have expressed the view that they think that these are in fact better than the fabled Jensons.
<span style="font-weight: bold;">The M-CAP Supreme</span> 2.2uF 800V- $21.90 – Much better value, but in a totally different league. The reason I’ve included these in my list is that some listening tests argued that there was no real noticeable difference between the higher tier of the Mundorf capacitors. This thread on the DIYaudio forum gave a range of opinions on them.
I’m not entirely sure how important the voltage of the capacitor is. Surely 100V is plenty for this application?
Attenuator
For volume control. The signature 30 uses the DACT 2. However, this is very expensive, so I’m looking for suggestions for much cheaper alternatives.
SLA Batteries
As I loved the portability of the Sonic T, I’m going to try and run the amp off batteries too. However, as this will probably be the last part of the making, I haven’t given this much thought yet. Is there anything I should consider?
All suggestions/comments very welcome!
Peter.
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