Is it worth building an amp for speakers
Sep 10, 2009 at 11:06 PM Thread Starter Post #1 of 18

cassegrain

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I'll soon buy bookshelf speakers and i'd like to know if there is a diy project for speaker amp better than a cheap nad amp (like nad c315) but not as much expensive as a beta 22.

François.
 
Sep 11, 2009 at 12:47 AM Post #4 of 18

Uncle Erik

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If you're willing to pay the price of a Beta22, you might want to consider the offerings at Transcendent Sound and Bottlehead. You can also buy Dynaco ST70 reproductions around that price, as well. Though you could also find a vintage ST70 for a bit less and restore it.
 
Sep 11, 2009 at 2:58 AM Post #5 of 18

linuxworks

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transpath (class T) amp is very very cheap.

many are already built. mine was $15 shipped from fleabay. (however I have quite a bit of noise on mine; maybe I got a bad one.)

I regularly use my 2ch b22 for speaker use. as long as you don't blast the spkrs with megabass, a 2ch b22 can easily power bookshelf spkrs (mine are 8" tannoys).

start with a T-amp, though; extremely cheap entry price.
 
Sep 11, 2009 at 12:23 PM Post #6 of 18

cassegrain

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I've read about the gainclone and it seems to fit my needs. So i'm thinking of building one but i have still a few questions.
Will it be enough to power 88db/6ohm bookshelf speakers?
I'm thinking of building gainclone in two enclosures + a passive preamp with a 10k pot and a switch for 3 sources in another enclosure. Is it ok or should i put the passive preamp and the gainclone amp in the same encosure?
 
Sep 11, 2009 at 2:32 PM Post #7 of 18

rshuck

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Gainclone should be plenty depending on the size of your room.

The passive pre should be fine in the same case, just take care routing your cables/twisting them to minimize RFI from the transformer.
 
Sep 11, 2009 at 3:02 PM Post #8 of 18

fishski13

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Quote:

Originally Posted by cassegrain /img/forum/go_quote.gif
I've read about the gainclone and it seems to fit my needs. So i'm thinking of building one but i have still a few questions.
Will it be enough to power 88db/6ohm bookshelf speakers?
I'm thinking of building gainclone in two enclosures + a passive preamp with a 10k pot and a switch for 3 sources in another enclosure. Is it ok or should i put the passive preamp and the gainclone amp in the same encosure?



the gainclone is silly good for the money. i built one that will be driving FR Fostex for a friend. while underpowered for my difficult to drive ATC SCM12, it showed my Krell a thing or two. i don't think you'll have any problems with a gainclone. btw, what are your speakers.

i built a gainclone from Peter Daniel's schematic. i didn't buy his boards - instead P2P. i have boards to build a bridged Pass Firstwatt F5 from him - they're top quality.

Commercial Gainclone kit- building instructions - diyAudio

audiosector.com
 
Sep 11, 2009 at 6:47 PM Post #9 of 18

Billyk

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If your interested in building a passive you may want to have a go at a Lightspeed. They are a hot topic over on diyAudio here is the groupbuy for the Silonex widgets that are at the heart of it. Combined with a nice chipamp I am sure you will enjoy the noise they make.
 
Sep 14, 2009 at 2:52 PM Post #10 of 18

cassegrain

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This preamp seems interesting, if i build a stereo 3875 based gainclone, do i need matched LEd for lightspeed?

And will the differences between gainclane and gainclone + lightspeed be important?
 
Sep 14, 2009 at 3:15 PM Post #11 of 18

rshuck

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Quote:

Originally Posted by cassegrain /img/forum/go_quote.gif
This preamp seems interesting, if i build a stereo 3875 based gainclone, do i need matched LEd for lightspeed?

And will the differences between gainclane and gainclone + lightspeed be important?



If you get the lightspeed, you MUST get them matched or you will have differing attenuation between the two channels. Do not skimp here or you will be disappointed. They are all singing the praises of the lightspeed, and I am also looking at implementing a balanced version for my b22. The advantage of the lightspeed is that it gives you the fine control of a pot with less noise.

Now, the lightspeed is a passive control, the same as a standard pot would be in this implementation, as would a stepped attenuator. You can choose any of the three for your passive pre.
 
Sep 14, 2009 at 3:27 PM Post #12 of 18

CodeToad

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I've read through the threads and I see lots of praise for the Lightspeed's sound, saying it "sounds" better.

Has anybody tested it?
 
Sep 14, 2009 at 3:31 PM Post #13 of 18

Billyk

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The lightspeed is based on a widget called an LDR, it is an photoresistor and LED together in a small plastic casing. What makes the lightspeed so cool is that there is only the photo resistor is in the audio path the rest of the circuitry is there to control the intensity of the LED thereby changing the resistance of the photoresistor and the volume; unlike pots with mechanical wipers on the resistive element or even an attenuator with switched resistors. This is the supposed key to these things. All I can say is it really does sound good, I am using one now in front of a chip amp. I like it better than any other passive I have heard although I have not heard many so I may not be the best judge.
You DO need a matched set of these, Udaily over at diyAudio is the go-to guy for these.
It's a fun project, I think you would be happy with the outcome.
 
Sep 15, 2009 at 9:02 PM Post #15 of 18

00940

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What bookshelf speakers do you consider ? The advice to be given depends a lot on the efficiency of the speakers, the size of your room, and so on.

I must say I'm very, very happy with the Symasym I build some times ago (mine is on +/-29V rails for around 30W into 8r): SymAsym5 - Project . It sounds way better than any gainclones I've heard. I built it for around 200€, buying the 225VA xformer and 8 good 4700uf/63V caps for cheap on ebay, using an old enclosure, and so on. With little cash on hand, you have to think a bit more.
 

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