do I need a pre amp?

mdagli1

mdagli1

mdagli1

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1. Gigabyte Z68X-UD5-B3 mobo
connected to
2. mini jack split into L/R phonos
connected to
3. Zalman Stereo Valve Amplifier/Chrome Kit
connected to
4. a pair of B&W M-1 speakers

Do I need to use a separate DAC at stage 2 like a CYP AU-D150?
 
Zalman stereo valve amp? They of CPU cooler fame?

I know Scythe make something like that. Personally, I'd look to getting a decent integrated amp. Scythe etc, know diddly squat when it comes to sound. No good having pretty decent speakers and a pants amplifier IMO. There are some pretty good T amps available, if you don't have the space for an integrated amp.

As for a DAC. Well a you'll get better sound quality from the DAC you mentioned, or something similar than onboard audio.
 
Marsman said:
Zalman stereo valve amp? They of CPU cooler fame?
Click to expand...

Yes, it's a K4040. K stands for build it your self kit. They do all sorts of amazing electronics kits.

Dad says it's way too expensive but I want to build one out of pure curiosity. (Plus that's the kind of work I enjoy doing.)

My issue is connectivity and whether it's appropriate.
 
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Well you've lost me there. I can't anything about a Zalman valve amp, and there is no mention of it on their website. All I can find that relates to K4040, is a valve amp made by Velleman.

Connecting it to the motherboard will not be a problem. I'm guessing this amp will have either 3.5mm or stereo RCA output. Connecting a subwoofer however, might be more difficult depending on how much you want to spend on one.
 
Whoops, my fault. Velleman, Zalman, sounded like the same thing...

If the sub is active, a cross over should be quite simple.
 
A $2000 tube amp kit? Sounds good!

But IMO a bit out of place considering the quality of the source and speakers. It's specs aren't great either, fairly high distortion (though pretty good for tube). Much better to go gradually in this game as I've been finding out.

If I was building a power amp it would be an AMB beta 24. It'll put out twice the power as that thing but with several hundred times less distortion (specs are here but most of the measurements are limited by the sound card! It's actual frequency response for example is flat from 0Hz - 1.4MHz, yes megahertz lol). Would cost a bit more than $2k if you did it nicely but it's probably the best performing amp in the world technically.

I recently put together a beta22 (headphone amp) and it's outstanding so I know this guy makes amazing designs.

Anyway to go back to your original question you're insane if you're going to feed a $2k+ amp with the output of a computer sound card (onboard no less!!). At the very least you'd want to get it a good external DAC (at least £200 new, less second hand perhaps) or DIY one. The buffalo dac from Twisted Pear is very highly regarded. As is the gamma1/2 from AMB. Again, technically they're considerably better than anything you can buy for less than several thousand quid. Even then the difference is doubtful.

To answer the preamp question, it looks like this tube amp doesn't have a volume control so yes you would want a high quality preamp for that. I'm planning to incorporate a preamp out into my beta22 for precisely that function (including an AMB delta1 card for volume control - exceptional tracking, look it up). Volume control can be done in the digital domain but again for a $2k kit amp you'd be mad to risk reducing the SQ.

Finally not sure how much electronics you've done, but if it isn't much you need to do a lot of research on general practices. For example, you'll want a good soldering station (I went for a Hakko 888 from here), good tools (DMM, wire cutter, screwdrivers, solder pump) and other bits and bobs (isopropyl alcohol, a loupe, etc.). For the final assembly you'll need things like heatshrink and a heatgun. It all addds up trust me :S
 
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Just been reading up on that Velleman. That's a fair chunk of cash. I'm not sure it's worth the money. I read a comment from someone that has heard one, and they thought the sound quality was not good enough to command such a price tag.
 
Wait... you're using some really nice high-end kit there from an onboard horrendous DAC.

Get a decent USB/Soundcard DAC, that's where this is going to pot.
 
To answer the thread question though, yes you do need a preamp in order to run a power amp like the velleman kit. I was planning on building a power amp at some point this year too. I drew up some plans for a Quad 909 clone which someone actually went and built. (and it even worked, although had some noise pickup issues) There are designs available from krell clones to naim nap200's. Elector do a book full of designs for building power amps and preamps that i found quite useful. DIYAudio is the place to look.

The others are quite right to say that you'd need a decent sound card or separate dac from the onboard sound to supply a system like you're planning.
 
Splitting a budget up for a speaker system isn't an easy problem actually. However in this scheme you'd be spending £1400 in this split:

~ £0 on the source (onboard soundcard)
£1250 on the amp
£150 on the speakers (B&W M1)

A much more sensible option would be something like

£200 source (e.g. CAMBRIDGE AUDIO DACMAGIC)
£300 amp (e.g. NAD C326BEE)
£400 speakers (e.g. TANNOY MERCURY V4)

which is only £900 and would sonically obliterate the first option. The examples are just things I found very quickly, haven't read reviews but gives you an idea. Saying that I own a Dacmagic and it's wicked, and the tannoys are frequently recommended around other forums. The integrated amp not sure but it got 4* in whathifi.

In the end the amp just needs to provide power with maximum neutrality. It's the speakers which are the most distorting component of the chain so they should cost the most IMO. With the source you don't need to spend much compared to the others as DAC is a pretty mature tech I guess.
 
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Putting quality and cost to one side for a moment, how has the progress been on PCI amps?
AKA, powered entirely off the PSU.

MUSE PC21 and the Marchand PM48 have been on the net for a while and wondering if there is anything about, lets say, 25W per channel?
 
mdagli1 said:
Putting quality and cost to one side for a moment, how has the progress been on PCI amps?
AKA, powered entirely off the PSU.

MUSE PC21 and the Marchand PM48 have been on the net for a while and wondering if there is anything about, lets say, 25W per channel?
Click to expand...

Interesting idea, I haven't seen anything like that before. But off the top of my head...

On paper it's a bad idea. Firstly, the power supply is the computer PSU. This is a switching power supply which introduces tons of noise into the rails, which is bad for the amplifier section. Second, inside the case is a noisy environment for sensitive electronics, and even if these cards had shielding it would be a losing battle. Third, the max voltage over PCI is 5 V (extremely low for an amp, by beta22 runs on + and - 30 volt rails) and max power 25 W, hence the low ish power of the cards.
 
Those cards I've mentioned don't actually connect to the PCI pins on the MOBO, they get 12V directly from a molex connection. So to get 25W you would need roughly 2.08A of current per channel. A modern 850W PSU can handle 80ish amperes per 12V rail so I don't really see an issue with power requirements. Especially when graphics card take far more.

Concerning noise and shielding, it just means there is going to be threshold of how much amplification can be done before noise becomes more noticeable.
I'm sure you can apply a basic filter to the power supply at those kind of low levels?
 
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Not a good amp at all. You get 22W out of it with a 4 ohm load at 10% THD. 25W will have even higher THD levels. At sensible levels of THD you still only get 10W and that's still into a 4 ohm load. If you connect a standard 8 ohm hi-fi speaker to that you aren't likely to see much over 5W before distortion ruins the sound. There doesn't appear to be any significant PSU input filtration so the likelihood of noise on poorly filtered PSU's is quite high.

A good hifi amp will give you 30W per channel into 8 ohms at something like 0.04% THD or less. My ancient luxman amp gives 50W at 0.02% into 8 ohms. Into a 4 ohm load the output power will increase by something like 40%.
 
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Cheap and nasty made in China, I wouldn't pay £25 for one but you're free to. 10% distortion is crazy. 1% is easily audible and spoils the music, imagine 10%.

I was looking for an integrated amp a few years ago and got a good 2nd hand cambridge audio one on avforums for £100. It's never let me down.
 
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