Can that amplifier drive speakers that on some frequencies go as low as 2 Ohm? (My question is not to criticize the amp, only for information).
I am sorry you take that as a criticism. I am a trained machinist, with a diploma, and speaking only from that background here. The reasons I went back to school for this was simple. I didn't want to pay what many shops try to charge for prototype cases and heat sinks. Another reason was so I knew what was involved in doing these things. Turns out it is pretty easy and saved me a great deal of money. Knowing what you should be paying is important if you plan to make money. I also went back to school for two semesters to study CAD drawing and technical drawing. After that I made my own drawings to send out for bids to multiple shops to ensure I received a fair bid.
As for the amp you linked to, it would be hard to beat $250 for an American made product of that quality, depending on the quantity manufactured. In larger quantities, say 250, it could done for $150 to $175, American made.
I agree that 1 ohm loads are ridiculous to design for in a consumer product. It is easy enough to do, but makes the amp far more evpensive for no benefit to at least 99% of customers. For the amps I made for the commercial sector, you must design for an expected 2 ohm load because it will happen no matter what you tell them.
I see we go in circles. Which plug is better? Has this been discussed?
http://crave.cnet.co.uk/gadgets/0,39029552,49303764,00.htm
(Have a little laugh guys.)
http://crave.cnet.co.uk/gadgets/0,39029552,49303764,00.htm
(Have a little laugh guys.)
I prefer the SABS 164 (South Africa), rated at 16A / 250V type. Especially the "old" ones that were made with real copper. Essentially the same as the old British standard. But the Brits changed because of safety I believe...not because of sound quality...Pfff..ridiculous.
The SABS 164's round pegs make for a smoother sound. You'll also see in the attached picture where Eichmann stole the bullet plug signal pin hole idea. Really it was around for ages in our power plugs in South Africa and India. The hole was to counteract the so called mass effect which caused phase errors and smearing (especially in the mid range)
When I emigrated to the Netherlands I noticed that my hifi sounded worse. I quickly suspected the power plugs. And after switching over to the SABS 164 plugs it was as if a veil was lifted and my soundstage was pitch black again.
The SABS 164's round pegs make for a smoother sound. You'll also see in the attached picture where Eichmann stole the bullet plug signal pin hole idea. Really it was around for ages in our power plugs in South Africa and India. The hole was to counteract the so called mass effect which caused phase errors and smearing (especially in the mid range)
When I emigrated to the Netherlands I noticed that my hifi sounded worse. I quickly suspected the power plugs. And after switching over to the SABS 164 plugs it was as if a veil was lifted and my soundstage was pitch black again.
Attachments
Nice, you can use the same socket to recharge your ipod and your own little nuclear sub at the same time
My 13 year old Crown Vic former police cruiser with anti-stab seats, eight proud cylinder 4.6L engine, with too many miles to count, is worth absolutely nothing, it also runs almost perfect and I don't want to think about the mileage because I value my psychological well being. I also refuse to accept any deals.
Wait 'til syn08 will beat me over the head with his diesel engine 2010 VW Jetta nanoL/rtKm mileage
Thanks. Where can I find those designs?
Also, I prefer good tubes designs over SS ones, unless there are some really excellent SS designs.
I didn’t think it was possible to not see Mr Ovidiu's contributions to this forum.
Anyway this is his latest design, read the thread and see what the response is. here
You will also find a lot of other designs on his website, and they are free of charge.
BTW: Mr Ovidiu is also known as syn08.
Cheers
Thanks.
I'd rather skip his designs.
I'd never try designs by some one who doesn't hear differences between cables, because it means to me that he wouldn't hear differences in design the affect the sound quality the way I hear it.
Hi Simon,
Could you expand on those numbers? What exactly are they when it comes to noise? I see there's a frequency dependency, so they're probably not V/rtHz. They seem to be Volts, but then 10nV RMS noise (-160dB) in the audio band, in a power supply output, is out of this world, even for JC
I worked once to a project involving a low noise satellite receiver, liquid nitrogen cooled, etc... having the noise performance about 5x better than what we are talking here and trust me, the power supply (+18V) had way more relaxed requirements.
Is there something specific to high end audio that requires better performance?
BTW, DIYers have only one customer, but that's already another discussion.
Been away sorry for the delay.
A good RC filter with vibration isolation will make 10nv per sqrt Hz RMS. A good film capacitor is required. An electrolytic will get close.
HOWEVER if you have a typical 60db PSSR the I would say look carefully at both positive and negative PSSR, then relax to -120db, allowing 20db of margin. That is why many find the microvolt level to be more than adequate.
I used to use -140db as a design value and have found every so often the noise would begin to crop up, so I changed my design target.
I have a decent sheet metal machine shop. Aluminum has been as low as $1.10 a pound and as high as $3.50 for 5052 Alloy. I assume Blowtorch cases are 6061 which is a bit more. A slab 17 x 12 x 3 would weigh about 60 pounds. You would need two of these and another for the covers. Markup for small runs is 2 to 5 times cost of material. Anodizing is 3.5 to 5 cents per square inch. Crazy customer doubles all prices... really.
You certainly made my day, Joshua 
I'm not sure what to say without ending up in the sin bin, so I’ll just let it be.
Here is some of my "cheap stuff". 100W mono block 200W at 4 ohm stable at 300W into 2 ohms. The bid to manufacture these at 1000 pieces was under $100 per pair, packed in shipping boxes. They were powder coated. There were no cheap sheet metal screws. I used press in captive nuts and button head Allen screws. Transformers were EI core made in house by the same manufacturer. I don't know what they cost because the bid was for the completed units.
http://www.diyaudio.com/forums/atta...krill-little-amp-might-monoblock-internal.jpg
I built some not so cheap amps also because a customer wanted them. They were 0.195 Al cases with 1" face plate and back panel. Material for the case was just under $250 with an additional $125 each ($500 for 4 cases) for machining. The finished amp weighed 110 lb and didn't look cheep at all.
I don't do cars, sorry.
Now it makes some sense, these numbers are also matching my experience. The HPS 3.1 Jung superregulators have around 100nV/rtHz (plus about the same amount of 1/f excess noise under 100Hz) and this, combined with a cap multiplier and the gain stage PSRR, is bringing the PS contribution to the total noise to almost nil.
All I am saying here is that it is much easier to build some decent PSSR in the gain stage (at least a cascode) rather than pushing unrealistic requirements (and allow for compromises, like the output impedance) in the power supply.
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