John Curl's Blowtorch preamplifier part II

[Joshua_G]

Originally Posted by john curl

It would be silly to expect my cheapest amp to drive 1 ohm loads consistently.

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).

[jacco vermeulen]

Joshua,

maybe you should try to build one of Mr Ovidiu's designs, they're far better than the majority of the junk out there.

[john curl]

No, Joshua, 2 ohms is a lousy load also, for a cheap amp. Do the calculations, it is a wonderful exercise for you. Do you really expect to make a 350-400W amp from a 125W /channel amp, just because you use a 2 ohm load? What about V-I limiting, overtemp?

[Steve Dunlap]

Originally Posted by john curl

Everyone, it must be realized the WE do NOT set the prices. The machinists set the initial price for us. We get started with one machinist, and we don't want to shop further, unless pressed. We have tried for years to make cheaper cases, WITH THE SAME QUALITY, but we have failed to do so, so far. Criticisms should be backed up by present knowledge, before it is put up.

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.

[ikoflexer]

I see we go in circles. Which plug is better? Has this been discussed?

http://crave.cnet.co.uk/gadgets/0,39...9303764,00.htm

(Have a little laugh guys.)

[Bas Horneman]

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.

[john curl]

Well, we leave it to you, Steve, to build the cheap stuff. What can you do with Autos?
Right now my 14 year old Acura with 26,000 mi is worth about $3,000. It runs almost perfect, gets 34 mpg at 70mph. Can you get me a better deal? ;-)

[ikoflexer]

Originally Posted by Bas Horneman

I prefer the SABS 164 (South Africa), rated at 16A / 250V type. Especially the "old" ones that were made with real copper.

Nice, you can use the same socket to recharge your ipod and your own little nuclear sub at the same time

[ikoflexer]

Originally Posted by john curl

Well, we leave it to you, Steve, to build the cheap stuff. What can you do with Autos?
Right now my 14 year old Acura with 26,000 mi is worth about $3,000. It runs almost perfect, gets 34 mpg at 70mph. Can you get me a better deal? ;-)

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

[Joshua_G]

Originally Posted by jacco vermeulen

Joshua,

maybe you should try to build one of Mr Ovidiu's designs, they're far better than the majority of the junk out there.

Thanks. Where can I find those designs?
Also, I prefer good tubes designs over SS ones, unless there are some really excellent SS designs.