first chipamp...need advice

thadman · 24th September 2006, 08:12 PM

Heres my situation...

Im looking for a cheap amplifier <$150 total that will power a pair of BG Neo8s + Dayton RS270s (crossed somewhere between 500-1000hz) on a 12" open-baffle (can anyone think of any better options for ~ <$250 total on speakers)

I spend a lot of time on my computer at home...and am getting tired of these Logitech stereo speakers. Im working an active setup for my car (BG Neo3s + Usher 9845s + Peerless XLS 8s + AA 18" run off D7056 + d51200.1) and currently have $2000+ tied up in that so I dont have a lot of money left over for a stereo setup at home...so Ive got to make with what I have. I consider myself extremely knowledgeable in terms of speaker design...but im totally lost when it comes to amps. Im looking for 100+ x 2 @ 8ohms and I'd like to hook up the amp directly to my computers soundcard (Im in the market for one of these too...so if anyone can recommend me one >$100 thatd be great. Im fine with buying off eBay)

Gcollier · 25th September 2006, 06:11 PM

A pair of LM4780 run in stereo will give you 4 channels, then you can Bi-amp the speakers. Alternatively you could also run them parallel and get the 100W output you are looking for. There are quite a few kits around for this chip, give it a Google. As for the soundcard I am in the market myself. Anything by M-Audio comes recommended. I have also been looking at the EMU 0404 as a cheap alternative. I suspect you, like myself, are also interested in the card to do some driver measurements.

G.

preiter · 25th September 2006, 08:02 PM

I'd just get a tried and true lm3875 or lm 3886 kit from www.audiosector.com or www.chipamp.com. You can easily build one for under $150.

True, these are "only" 50 watts, and you asked for 100. But if your need for 100 watts was based on your experience with commercial amplifiers, I think you will find that a 50 watt DiY chip amp delivers all you need and more. Doubling the power only gets you 3 dB more volume anyway.

For open baffle speakers, two drivers that are getting a whole lot of interest right now are the Silver Iris 15" coaxials from www.hawthorneaudio.com and the B200s from Visaton. Do a search in this forum to find a ton of info about both.

These will run you closer to $300 a pair shipped than $250, but you don't have to worry about a crossover for either (the SI comes with a crossover and the B200 is a single full-range driver).

thadman · 25th September 2006, 08:13 PM

could a DIY chipamp best a used Adcom GFA 5500? Im just curious as those are about $150-200 used on eBay and they seem to be regarded pretty highly.

preiter · 25th September 2006, 08:35 PM

I haven't heard an Adcom amp in about 10 years, can't comment on those.

If you are willing to explore a lower power route, you could try either the Charlize amplifier from www.diyparadise.com, the T-Amp (which needs to be modified to really sound good) or the Super-T Amp (basically an already modded T-Amp in a nicer case).

Those are all 10-15 watts. It doesn't sound like much but the two drivers I mentioned early are both very efficient. The SI and the B200 are both around 96 dB per watt. The drivers you mentioned originally in this message would have a combined efficiency around 90 dB per watt. A 6 dB increase in efficiency is equivalent to 4x the power.

Dick West · 25th September 2006, 08:39 PM

I don't understand why guys like to spend so much money and time building a chip amp when they can get a great used amp for equal or fewer $$.

For years I have used nothing but Hafler legacy amps, the ones from the early 80s, that came both as a kit or factory wired. My favorites at around 65 watts (conservative watts!) are the DH-120 or P-125 or the Hafler 9130. Or, you could go for 110 watts per channel with the DH-220 or P-225 amps. These amps are solid performers, complete schematics and parts lists are available, and use no exotic parts so repair (infrequent) is easily possible.

Check them out on eBay and read their manuals in the Tech archive section of www.hafler.com. Here is the link to the DH-120 amp's manual:

http://hafler.com/techsupport/pdf/DH-120_amp_man.pdf

Also, you could do a search for these amps here at DIYaudio in the solid state amp forum.

My $0.02

Dick West · 25th September 2006, 08:49 PM

Check my previous post selling a Hafler 9130:

Hafler 9130 amp to sell

Read the several messages in this short thread and look at the pictures.

I'll be glad to answer any questions you have about these Hafler amps. Perhaps you might search on my name here and see the many posts to various forums discussing Hafler amps.

Presently I am using a DH-120 with a pair of DIY (mid/bass + tweeter) speakers attached to my computer and enjoy the sound playing CDs, watching a DVD, etc.

Dick

Dick West · 25th September 2006, 09:08 PM

Here is the link to the sound card I am using. It has great sound for the $$:

http://www.newegg.com/Product/Produc...82E16829120103

Read the reviews and after you get it download the better drivers from VIA ARENA.

A bargain buy!!

Gcollier · 25th September 2006, 09:19 PM

Quote:

Originally posted by Dick West
Here is the link to the sound card I am using. It has great sound for the $$:

http://www.newegg.com/Product/Produc...82E16829120103

Read the reviews and after you get it download the better drivers from VIA ARENA.

A bargain buy!!

As I understand it only the rear channels on that card use the really good DAC. But I have read good things about it.

Dick West · 25th September 2006, 11:44 PM

Gcollier,

You are correct. This is not a 5.1 channel gamer's card. The back 2 channels can be used to drive a stereo amp and they are purported to have an excellent DAC driving their analog output.

I am using this card in my main machine in the HT room where I surf, watch TV, and play DVDs. I use its digital (toslink) output sent to my Outlaw 950 pre/pro which contains an excellent DAC. The sound from my PC's CD player, sent through this card's tosllink into the pre/pro and played on a very good 5.1 set of HT speakers (and driven by 3 Hafler amps), sounds just as good as a dedicated system in the family room. And, the use of the toslink connection cuts out chances of hum or ground loop problems.

So, this card is good for digital (toslink) output or analog stereo output (configured to use the back two speakers outputs). If you're not a gamer it is an excellent product for the price. The ENVY chipset is also used on much more expensive cards, such as the M-audio line as I recall.

Dick

24th September 2006, 08:12 PM	#1
thadman diyAudio Member Join Date: Dec 2005 Location: west lafayette	first chipamp...need advice Heres my situation... Im looking for a cheap amplifier <$150 total that will power a pair of BG Neo8s + Dayton RS270s (crossed somewhere between 500-1000hz) on a 12" open-baffle (can anyone think of any better options for ~ <$250 total on speakers) I spend a lot of time on my computer at home...and am getting tired of these Logitech stereo speakers. Im working an active setup for my car (BG Neo3s + Usher 9845s + Peerless XLS 8s + AA 18" run off D7056 + d51200.1) and currently have $2000+ tied up in that so I dont have a lot of money left over for a stereo setup at home...so Ive got to make with what I have. I consider myself extremely knowledgeable in terms of speaker design...but im totally lost when it comes to amps. Im looking for 100+ x 2 @ 8ohms and I'd like to hook up the amp directly to my computers soundcard (Im in the market for one of these too...so if anyone can recommend me one >$100 thatd be great. Im fine with buying off eBay)

25th September 2006, 06:11 PM	#2
Gcollier diyAudio Member Join Date: Mar 2003 Location: Windsor	A pair of LM4780 run in stereo will give you 4 channels, then you can Bi-amp the speakers. Alternatively you could also run them parallel and get the 100W output you are looking for. There are quite a few kits around for this chip, give it a Google. As for the soundcard I am in the market myself. Anything by M-Audio comes recommended. I have also been looking at the EMU 0404 as a cheap alternative. I suspect you, like myself, are also interested in the card to do some driver measurements. G. __________________ If you take something apart and put it back together again enough times, eventually you will have two of them.

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25th September 2006, 08:02 PM	#3
preiter diyAudio Member Join Date: May 2006	I'd just get a tried and true lm3875 or lm 3886 kit from www.audiosector.com or www.chipamp.com. You can easily build one for under $150. True, these are "only" 50 watts, and you asked for 100. But if your need for 100 watts was based on your experience with commercial amplifiers, I think you will find that a 50 watt DiY chip amp delivers all you need and more. Doubling the power only gets you 3 dB more volume anyway. For open baffle speakers, two drivers that are getting a whole lot of interest right now are the Silver Iris 15" coaxials from www.hawthorneaudio.com and the B200s from Visaton. Do a search in this forum to find a ton of info about both. These will run you closer to $300 a pair shipped than $250, but you don't have to worry about a crossover for either (the SI comes with a crossover and the B200 is a single full-range driver).

25th September 2006, 08:13 PM	#4
thadman diyAudio Member Join Date: Dec 2005 Location: west lafayette	could a DIY chipamp best a used Adcom GFA 5500? Im just curious as those are about $150-200 used on eBay and they seem to be regarded pretty highly.

25th September 2006, 08:35 PM	#5
preiter diyAudio Member Join Date: May 2006	I haven't heard an Adcom amp in about 10 years, can't comment on those. If you are willing to explore a lower power route, you could try either the Charlize amplifier from www.diyparadise.com, the T-Amp (which needs to be modified to really sound good) or the Super-T Amp (basically an already modded T-Amp in a nicer case). Those are all 10-15 watts. It doesn't sound like much but the two drivers I mentioned early are both very efficient. The SI and the B200 are both around 96 dB per watt. The drivers you mentioned originally in this message would have a combined efficiency around 90 dB per watt. A 6 dB increase in efficiency is equivalent to 4x the power.

25th September 2006, 08:39 PM	#6
Dick West diyAudio Member Join Date: Aug 2004 Location: Illinois	I don't understand why guys like to spend so much money and time building a chip amp when they can get a great used amp for equal or fewer $$. For years I have used nothing but Hafler legacy amps, the ones from the early 80s, that came both as a kit or factory wired. My favorites at around 65 watts (conservative watts!) are the DH-120 or P-125 or the Hafler 9130. Or, you could go for 110 watts per channel with the DH-220 or P-225 amps. These amps are solid performers, complete schematics and parts lists are available, and use no exotic parts so repair (infrequent) is easily possible. Check them out on eBay and read their manuals in the Tech archive section of www.hafler.com. Here is the link to the DH-120 amp's manual: http://hafler.com/techsupport/pdf/DH-120_amp_man.pdf Also, you could do a search for these amps here at DIYaudio in the solid state amp forum. My $0.02

25th September 2006, 08:49 PM	#7
Dick West diyAudio Member Join Date: Aug 2004 Location: Illinois	Check my previous post selling a Hafler 9130: Hafler 9130 amp to sell Read the several messages in this short thread and look at the pictures. I'll be glad to answer any questions you have about these Hafler amps. Perhaps you might search on my name here and see the many posts to various forums discussing Hafler amps. Presently I am using a DH-120 with a pair of DIY (mid/bass + tweeter) speakers attached to my computer and enjoy the sound playing CDs, watching a DVD, etc. Dick

25th September 2006, 09:08 PM	#8
Dick West diyAudio Member Join Date: Aug 2004 Location: Illinois	Here is the link to the sound card I am using. It has great sound for the $$: http://www.newegg.com/Product/Produc...82E16829120103 Read the reviews and after you get it download the better drivers from VIA ARENA. A bargain buy!!

25th September 2006, 11:44 PM	#10
Dick West diyAudio Member Join Date: Aug 2004 Location: Illinois	Gcollier, You are correct. This is not a 5.1 channel gamer's card. The back 2 channels can be used to drive a stereo amp and they are purported to have an excellent DAC driving their analog output. I am using this card in my main machine in the HT room where I surf, watch TV, and play DVDs. I use its digital (toslink) output sent to my Outlaw 950 pre/pro which contains an excellent DAC. The sound from my PC's CD player, sent through this card's tosllink into the pre/pro and played on a very good 5.1 set of HT speakers (and driven by 3 Hafler amps), sounds just as good as a dedicated system in the family room. And, the use of the toslink connection cuts out chances of hum or ground loop problems. So, this card is good for digital (toslink) output or analog stereo output (configured to use the back two speakers outputs). If you're not a gamer it is an excellent product for the price. The ENVY chipset is also used on much more expensive cards, such as the M-audio line as I recall. Dick

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