Hey everyone,
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 6moon'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:
Air core – 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.
Toroidal – 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 ferrite cores to other cores, such as MMP.
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:
Jenson:
Copper Foil 2.2uF 100V - $60.95 – *Very* pricey, but exactly what the Sig 30 uses. Supposedly legendary.
Mundorf:
Silver in Oil 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.
The M-CAP Supreme 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 here: http://www.diyaudio.com/forums/showthread/t-50254.html 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.
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 6moon'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:
Air core – 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.
Toroidal – 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 ferrite cores to other cores, such as MMP.
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:
Jenson:
Copper Foil 2.2uF 100V - $60.95 – *Very* pricey, but exactly what the Sig 30 uses. Supposedly legendary.
Mundorf:
Silver in Oil 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.
The M-CAP Supreme 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 here: http://www.diyaudio.com/forums/showthread/t-50254.html 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.
You're on the right track, for sure.
The aircore inductors do have a smooth top end, but they are not without their problems: High DCR, RFI radiation. Toroidal inductors do seem more dynamic and better in the bass, but they have their problems too. Everything is a compromise.
Paper in oil caps sound very nice to me, but they are not everyone's cup of tea. They can be too "smooth" for some folks. Some can be muddy in the low end. The mid range is hard to beat, tho.
16V is all you need on the input caps, you can use a higher value, of course.
Batteries. Hmmmm.... I'm still not convinced. All the measuring and listening I've done does not show me that batteries are better. The opposite seems to be true.
Batteries, such as the SLA type used for modded T-Amps, are very quiet with no load. Once you turn the amp on, Zap! You've got noise a-go-go. A good linear or switch mode power supply is actually quieter than the battery. And regulates better too. Of course you can do some filtering on the SLA, but it will never be quieter than a good regulated supply on a class-d amp.
Batteries are good for very low noise devices, like preamps. Class-D amps just don't need them, IMO.
I hope that answers some of your questions. Best of luck with the project- and enjoy the music!
The aircore inductors do have a smooth top end, but they are not without their problems: High DCR, RFI radiation. Toroidal inductors do seem more dynamic and better in the bass, but they have their problems too. Everything is a compromise.
Paper in oil caps sound very nice to me, but they are not everyone's cup of tea. They can be too "smooth" for some folks. Some can be muddy in the low end. The mid range is hard to beat, tho.
16V is all you need on the input caps, you can use a higher value, of course.
Batteries. Hmmmm.... I'm still not convinced. All the measuring and listening I've done does not show me that batteries are better. The opposite seems to be true.
Batteries, such as the SLA type used for modded T-Amps, are very quiet with no load. Once you turn the amp on, Zap! You've got noise a-go-go. A good linear or switch mode power supply is actually quieter than the battery. And regulates better too. Of course you can do some filtering on the SLA, but it will never be quieter than a good regulated supply on a class-d amp.
Batteries are good for very low noise devices, like preamps. Class-D amps just don't need them, IMO.
I hope that answers some of your questions. Best of luck with the project- and enjoy the music!
You may know, but Mundorf Supreme Silver/oil caps are not paper/oil, but "oil impregnated metallised polypropylene dielectric" capacitors. Many places erratically quote them as having paper dielectric. For example Tony Gee here: http://www.humblehomemadehifi.com/Cap.html. Paper caps, as we probably agree, tend to have a sound of their own.
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