Beginner Solid State Amp (and speakers)

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#41
Mrcloc said:
I agree to an extent, but a friend of mine built the 3-5 W circuit for a stereo amplifier powering two Celestion F15's and the bass was great. I mean, it's not for a subwoofer, but it was enough for listening to music, and not soft either.

Anyway, it's a 3 transistor circuit and it's a nice one. I agree it's possible to build a more powerful design, and possibly more suitable. As I said, there are plenty of fantastic things to build here, but if desired, I would be happy to design a PCB for the small class A design.
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I'm still a firm believer that subwoofers have no place in music reproduction. They belong in a home theater system, not Hi-Fi. A properly designed speaker should run full range on it's own. The sound from a stereo should come from two sources, otherwise the soundstage becomes confusing. The amplifier needs to have enough power to drive the speaker through it's whole range as well.

Power required to do this will change drastically with room size and speaker design/driver choice. In my experience, any amp of that power will sound louder than a higher powered amp, because it doesn't properly drive the bass producing woofer, causing it to create more noise. The main objective is to recreate music, not create noise.
 
#42
I did notice that my small 60w rated class D amps could not produce bass properly like a 50w rated class AB amp and the music sounded thinner. The same speaker connected to a "real" amp sounds much fuller and more balanced because the bass extension and authority un-achievable previously suddenly is there. I had a pair of sealed RS225-8 woofers in a 24L box that I used to power with small class D and even with a DSP Linkwitz Transform, the bass was never as good as when driven by a bigger class AB discrete amp - even passively with no LT via DSP. I think it came down to the headroom needed on bass transients. That RS225-8 actually makes really nice low distortion and tight bass with the right amplifier.
 
#43
jwilhelm said:
I'm still a firm believer that subwoofers have no place in music reproduction. They belong in a home theater system, not Hi-Fi.
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This is an interesting point, but not everyone has this sort of money.

Bass can be reproduced at whatever power - have a good listen to heaphones.

In a small room, 1W can make bass on the right speakers that you can really feel it. I know because I've experienced it. That said, if you want loud music with the bass soundstage, then you do need power for headroom.
 
#44
xrk971 said:
I did notice that my small 60w rated class D amps could not produce bass properly like a 50w rated class AB amp and the music sounded thinner. The same speaker connected to a "real" amp sounds much fuller and more balanced because the bass extension and authority un-achievable previously suddenly is there.
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I have experienced exactly this, and with a comparison with the two amplifiers next to one another. The class D couldn't compete with the fullness of the AB. There was nothing wrong with its quality, it was just the fullness.

In my experience, I may say that I feel the authority of bass with a class A wins. I haven't tested this recently, but that was my experience when I compared a 20W class A I designed to a 120W class AB I designed on the same speakers.
 
#45
AndrewT said:
100mW average to 5W (maximum power) allows for 17dB peaks.

If you need much more than 100mW to 1W of avearge power, then you buy/build a more powerful amplifier.
But that personal requirement does not necessarily apply to all Members.
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I'm sure you've heard the term dynamic headroom before. This is what I'm getting at. 5W amplifiers go well with the IPod crowd with their crappy mp3s that "sound just as good" as the real thing. It'll do it for you, unless you actually listen to it.

Others can listen to whatever they like, but I myself, especially with the state of my hearing, can't listen to badly reproduced sound. The unconscious thought process that goes into hearing really slows down with hearing damage, so it causes huge problems with concentration.
 
#46
Mrcloc said:
This is an interesting point, but not everyone has this sort of money.

Bass can be reproduced at whatever power - have a good listen to heaphones.

In a small room, 1W can make bass on the right speakers that you can really feel it. I know because I've experienced it. That said, if you want loud music with the bass soundstage, then you do need power for headroom.
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I had Koss Red Devils way back. they got replaced with Koss Pro 4AA and that gave much better reproduction, including bass.

I thought my new Sennheiser hd 465 were better still.
Until I decided to use headphones to test the noise+ripple on a power supply.
The red devils showed no hum whatsoever.
The Pro 4AA had just a tiny bit of hum but it was so quiet I would class my test as a pass.
Then I listened through the hd 465. The hum was very pronounced.
This shows what 4 decades of technology development has done for low frequency extension of bass response in headphones.
 
#47
Mrcloc said:
This is an interesting point, but not everyone has this sort of money.

Bass can be reproduced at whatever power - have a good listen to heaphones.

In a small room, 1W can make bass on the right speakers that you can really feel it. I know because I've experienced it. That said, if you want loud music with the bass soundstage, then you do need power for headroom.
Click to expand...

Yes higher power will cost more, but this is a hobby...

If money's that tight, there's usually a bunch of old receivers around headed for the trash heap these days that can be junked out for parts. Here in North America, most actual components are ridiculously cheap.
 
#49
I've decided on the JLH class A preamp (built last), the VHex+, and the X-LS Encore speakers. Will likely go over $500, but it sounds like the money will go a long way.

The U-Turn turntable seemed like the weak link, so I'm leaning towards a middle end Pro-Ject tt now.

I'm really looking forward to seeing it. Even better, hearing it.

Thanks all for the help. The conversation has gotten interesting, don't stop just because I decided on these projects-
 
#54
Vzaichenko and Jwilhelm are excellent and very prompt at answering user build questions so you will have help on Vhex amp for sure.

Speaker is easy - just solder up wires to pre-built XO and mount and connect drivers to box you make. GR Research also provides excellent customer service if you have any questions.

The JLH preamp is pretty simple build and should work first time and it has a thread so lots of people can help you there.
 
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