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DIY Amp Projects/Kits

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Posted on March 30, 1999 at 10:10:57
I'm looking around for a good kit or project with available PCB's for building my own high end amplifier. Any suggestions would be appreciated.

This is what I'm looking for
100 W into 8 Ohms
200 W into 4 Ohms
400 W into 2 Ohms (not nessessary but would be nice)

Prefer Class 'A'
Tube or Transistor no real preference.

Mostly for Home theatre, but music as well.
Speakers I eventually intend to use are the Newform 45" ribbons (still havn't picked a woofer to go with them), they will be bi-amped use active crossovers.

Price range would be around $750 be channel.

Any ideas??

So far I am looking at
The Leach Amp
Marchand MB200
Vellemen K4020

 

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Re: DIY Amp Projects/Kits, posted on March 30, 1999 at 10:38:04
qqq


 
Sorry if I don't get it but what/why would you want to build a kit if you want so much power at the first place??

Do you know the exponential in technical difficulties if you try to build and amp beyond 30Watts? (that's a Dyna ST-70 equiv., MOSFETs SState amp maybe more?!)
For 100Watt tube amp you'll be using alot of expensive/exotic tubes and will cost you thousands of bucks to get a factory unit. Just forget about kit form 'cos nobody makes tube amps beyond 60Watts (period).

I don't mean to "shunt" you or discourage you but look! if you ever surf around you'll notice nobody offers tube amp kits over 60Watts. SState? I 'm not aware of it.

Think realistically and let us know what you really wants (100W??)

CuteCueQ

 

Re: DIY Amp Projects/Kits, posted on March 30, 1999 at 16:12:36
Well these are the specs for the speaker I intend to use

Sensitivity 91 dB/W at 1m
Max Power Handling 200 Watts
Nominal Impedance 6 Ohm

What would you suggest as my power needs for these drivers?? Remember this
will be for home theatre as well as audio. I appreciate any suggestions

 

Re: DIY Amp Projects/Kits, posted on March 30, 1999 at 17:56:47
you don't need half as much power as you thought. 50 watts would be killer, you could pull it off nicely with 20 watts. even 10 watts would work if you wanted to though, but your dynamics might suffer a little and it wouldn't go very loud (probably about 90db at your average listening position). I have speakers with an 86db sensitivity and a 6 ohm load and they get obscenely loud with 50 watts. In all reality, most amps are only producing a watt of power to achieve loud levels. You speakers for example can go up to 91 db at 3 ft. Now you probably sit about 9 ft away from your speakers or so requiring a total 4 watts to produce 91 db. (think I got the math right) Now 91 db is pretty loud, I think anything over 95 is too loud and hurts my ears. I'm only listening to music at about 70 db right now, meaning that I'm using less than a watt! I'd shoot for a 20 watt design if I were you. And go with tubes for DIY, much easier than all that soldering ;-)
happy building,
Rob

 

Re: DIY Amp Projects/Kits, posted on March 30, 1999 at 23:24:29
Quest


 
Hello,

Before we confuse the heck out of you I must let you know first hand with the following facts: (some of you folks might not agree with me afterall:-)

(1) Speakers are rated at (decibels/Watt/metre) efficiency. Tube amps love impedences starting at 4 ohms nominal ("nominal" means the resistance value varies with respect to the frequency the speaker is reproducing, more on this later..). SET("single-ended triode") and other low-powered DHTs prefer a stable nominal impedences of 8 ohms or more (16ohms is even better). Efficiency-wise the mroe efficient the speaker is the more costly it is for the manufacturer to make: costly magnet structure and so on... Good speakers don't come cheap...and IMHO cheap speakers coan only do "so much" only (or should I say so little??)

(2) for every 3 dB increase in sound level you will have to double your watts: example : for a 91dB/W/m speaer if you sit 1 metre in front of the speaker it takes 1 watt to bring the speaker to 91dB, 2Watts to 94dB, 4 watts to 97dB, 8Watts to 100dB, 16Watts to 103dB ///you figure the rest.

(3) no matter how "powerful" an amp manufacturer might rate their products, it is true that the best sound comes at around a few watts most of the time. This is because distortion is proportional to the output generated: the higher the output the more distortion produced. therefore amps sound sweetest during the first few watts. This is particularly true to SE amps.

(4) Nobody can tolerate a loud sound pressure over an extended period of time .Living in a relatively low ambient noise environment 70's dB is what most people prefers. If you play music to a so-called "concert level" you'll have either a lot of gross accoustical feedback from your room making the sound gross/muddled/boomy...or you'll get ear bleed.

(5) beware of SolidState amp's rating. If you try to push it to its max. you might push it to the "clipping" region, risking your set of tweeters with it.

All the marketing scams and such had mis-informed the public about power ratings of amp and the efficiency of speakers and such. I personally do not believe in all those fancy ratings and such. A 71dB/W/m speakers (Technics/Panasonic makes one this year in Japan, REALLY!!) probably takes an upward of 200Watts to drive and that ain't cool!

Gone are the good ol days where speakers are efficient and tube amps sounded warm. Nowadays cutthroat competition drives manufacturers into making cheap low efficiency speakers and they want you to believe that is the norm. or is it?

Another naked truth behind all these is that unlike tube amp gear which requires a certain amount of care and maintenance SState amps have been cheap and maintenance-free. It is easy to make a 50Watts SState amp than making a 5Watt tube amp (you can get a Kenwxxd amp rated at 100Watts per channel at Circuit cxxy for $200 bucks!!)

Do you know good sounding SState amp cost a lot of dough to make (several thou for Krells, Accuphase, etc.) Good sound still doesn't come cheap after all these years.

these are my humble opinions.

regards,
Quest

 

Re: DIY Amp Projects/Kits, posted on March 31, 1999 at 00:11:46
Alan Ersen


 
Have you taken a look at this?
http://www.vision.net.au/~anthony/symmetric.htm

 

Re: DIY Amp Projects/Kits, posted on March 31, 1999 at 11:44:46
i remeber the doubling rule for extra 3db, do you know the distance deal? 91db sensitive speakers require 1 watt to preduce 91 db at 1 meter, but what is it at 2 meters? I've forgot that part.

 

distances..., posted on March 31, 1999 at 13:43:15
Quest


 
I recall something like every doubling the distance requires another 6dB increase (or quadruple power).... So if the 1st watt gives you 91dB/W/m then instead of the 4th Watts brings you to 97db if you sitting 1m in front of the speaker, you'll get91dB at 2 meters.

Correct me if I'm wrong.
Quest

 

Don't forget...., posted on March 31, 1999 at 14:12:57
Tom S.


 
....that you are using two speakers for stereo. Add 6dB (or is it 3dB?) to your original (xxdB/1W/1meter) efficiency figure because you are doubling your drivers for stereo reproduction.

Have fun,
Tom S.

 

Re: DIY Amp Projects/Kits, posted on March 31, 1999 at 20:43:09
Kelly, I thought I would do the same thing that you are compteplating about six months ago. Looked at various designs on the web, did some searching for parts, price checks, trying to find matched MOSFETS, the whole nine yards. Come to find out it was going to cost me more to build one than I could buy one for. Let me make a suggestion because I have heard the Newforms with this amp. Monarchy SE Class A Monoblock. I have the DELUX version which doubles into 4 ohm and 2 ohm and cost $1179. The Basic version does 160 watts into 4 ohm and is $890. I know this is a little above what you said but, they really seem to work with the ribbons very well. If you are going for five of them, I am sure you could get some knocked off the price if you haggle with them. If you would have bought them before April 1st you could have got them for $623 a piece. Still might be able to get them for that if you buy five. I don't normally push a piece of gear, but I know what these sound like with the Newform. If you care anything about music, these will make a difference. You by direct from them. The web site is below.

Clayton

Monarchy Audio

 

Yes, Inverse Square Law, posted on April 1, 1999 at 09:09:20
You are quite right. If you increase the measuring distance a factor of 2 linear units (2 times), then your audible power measurement will decrease by a factor of 4 linear units (4 times). This is because 2 squared equals 4 in this Inverse Square Law problem (measured power drops by the square of the distance increase). In order to maintain the same audible power measurement that you originally had when the measurement distance was closer, you must now increase the amplifier power by 4 linear units.

A power increase by a factor of 4 linear units (4 times) is converted to a decibel power increase by [ 10 Log 4 ], which is 6 dB.

Kind Regards, Chris

 

Re: DIY Amp Projects/Kits - Try this, posted on April 6, 1999 at 07:42:56
Lasse


 
Here in Denmark we are producing a lot of both tube and SState amps (High-End as Gryphon, Primere, BOW-Technology). And of cause a lot of people are making their own DIY projects. Try to have a look at this homepage: http://home5.inet.tele.dk/lcaudio/international/index.html
This is from a Danish Audio Technician that throughout the eighties and nineties have made a lot of constructions brought in the Danish magazine High Fidelity (reviews in the Norwegian Audio as well). He have started a company that sells complete kits both preamplifiers, poweramps, cables and calibrated oscillators for CD players (Clock generator). I would recommend the Patriot 100 or more likely the ZapSolute mk. 4.0 in the 40W edition. This is a 40 class A power amp. That drives almost every thing. You can send E-mail to Lars Clausen from LC Audio at lcaudio@post5.tele.dk. I don't think that English should be any problem at all.

Regards Lasse

 

Re: DIY Amp Projects/Kits - Try this, posted on April 6, 1999 at 07:43:06
Lasse


 
Here in Denmark we are producing a lot of both tube and SState amps (High-End as Gryphon, Primere, BOW-Technology). And of cause a lot of people are making their own DIY projects. Try to have a look at this homepage: http://home5.inet.tele.dk/lcaudio/international/index.html
This is from a Danish Audio Technician that throughout the eighties and nineties have made a lot of constructions brought in the Danish magazine High Fidelity (reviews in the Norwegian Audio as well). He have started a company that sells complete kits both preamplifiers, poweramps, cables and calibrated oscillators for CD players (Clock generator). I would recommend the Patriot 100 or more likely the ZapSolute mk. 4.0 in the 40W edition. This is a 40 class A power amp. That drives almost every thing. You can send E-mail to Lars Clausen from LC Audio at lcaudio@post5.tele.dk. I don't think that English should be any problem at all.

Regards Lasse

 

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