Diy reference amp decision

[rotation]

Hi to all!
First sorry for disturbing you by asking question like this; i searched all known audio forums, but couldn't find a good answer, at least not professional...
I have KRK ST8 nearfield monitors, but no amp. I was sarching for a good diy project, but realised it's very hard to diy good amp without lots of money and knowledge.
Now i'm looking at two kadidats. First are Hypex UCD modules, models 180 or 400, second is diy Leach 4.5 amp. I could also buy the Alesis RA300, but diy is much more interesting.
So what would you suggest? Monitors have poor bass, at least with Quad 405, GC, some hi-fi amps..I think i need something with stronger bass or at least with possibility to modify.
I would be more than happy if someone could help me deciding. Is the Hypex way to go, maybe Leach?
Please help me, and have a good day!
Miha

 

[Samuel Groner]

If I'd want to build my own amp without designing anything I'd probably go for a design by D. Self. You can get PCBs and kits from: www.signaltransfer.freeuk.com

Have a look at the "Trimodal Power Amplifier".

Samuel

 

[Mendelt]

I helped a friend to do an amp with the hypex UCD modules (UCD180 is plenty for a reference amp). We compared the resulting amp with a Quad 303 and a 405 (he's a quad enthusiast, I don't really like those amps ) and I was blown away by the results. Much more detail and really tight low end. Not really flattering on a lot of material (some bad recordings like earlier Jamiroquai or the new Placebo cd did sound better on the Quad) but I guess that's what you need for a reference amp.

If you're really into diy it's better to build the Leach of course. Building an amp with modules isn't really exiting.... or you can look on the diyaudio forums, there are some people doing real-diy ucd-like projects. You'll even have to do the boards yourself.

 

[rotation]

Samuel: there is a lot of projects like this, but my experiences are that it's very difficult to diy very good amp.
Mendelt: It really seems UCD is excellent amp. My brother has good diy Quad, we tried it on my speakers. It was very nice, but it didn't have lots of bass, details were ok, but not excellent. Comparing to commercial amps i know it's very good amp in my opinion.
Do you really think i could improve bass with UCD. This is a big problem with KRK ST8. Middle and high are very good, lots of detail, linear. I really enjoy linstening and mixing..
Btw, can i improve bass rsponse by putting more capacitors in PSU? People at Diyaudio are saying this.

Ok, thanks a lot for the replys. It's helpful to get opinion from this forum. If anyone has something to say about this monitors and amp please say it.
Miha

 

[peterc]

If you want to do something REALLY interesting, go to www.diyaudio.com & find one of the Krell DIY projects! Or one of the Pass Labs projects, there is a whole forum just for those.

Be prepared for some large heatsinks......

Some links:
http://www.diyaudio.com/forums/showthread.php?s=50d22ad3dbee811985d4401906d7abd7&threadid=31077
http://www.audio-circuit.dk/
http://www.delta-audio.com/

Peter

 

[Mbira]

what about the gainbloaks projects?

 

[Minion]

If you want to built a simple,cheap but powerfull Power amp you might want to check out the LM3886 Type poweramp IC"s.....

They only need about 10 external Components and each chip can deliver up to 68w into 4 ohms and multiple chips can be paralelled to achieve really high output power.....

The chips are only about $5 each and about $5 in external components (Minus the PSU and Chassis and speaker)....


Here are the specs of the Chip and the Curcuit:

http://www.national.com/pf/LM/LM3886.html


I am useing one for building a Guitar amp and a Bass amp useing a opa2134 Preamp front end with has "Bass,Mid,Treb,Bright,Gain, Volume, Mute and a High and Low gain input...This pre could also be used on a Power amp also I suspect....

Let me know if you want the schematic....

Cheers

 

[Samuel Groner]

Samuel: there is a lot of projects like this, but my experiences are that it's very difficult to diy very good amp.

I don't think that there are many designs out there that perform as well as the one I pointed you to.

Do you really think i could improve bass with UCD. This is a big problem with KRK ST8. Middle and high are very good, lots of detail, linear. I really enjoy linstening and mixing..
Btw, can i improve bass rsponse by putting more capacitors in PSU? People at Diyaudio are saying this.

BS. If you want better bass response you need better speakers, not more uFs or another amplifier (assuming the amplifier got a reasonable PSU and is used well below clipping).

Samuel

 

[Mendelt]

[quote author="rotation"]
Mendelt: It really seems UCD is excellent amp. My brother has good diy Quad, we tried it on my speakers. It was very nice, but it didn't have lots of bass, details were ok, but not excellent. Comparing to commercial amps i know it's very good amp in my opinion.
Do you really think i could improve bass with UCD. This is a big problem with KRK ST8. Middle and high are very good, lots of detail, linear. I really enjoy linstening and mixing..
Btw, can i improve bass rsponse by putting more capacitors in PSU? People at Diyaudio are saying this.
[/quote]

To improve your bass you'll first have to identify the problem.

If you have an amp that performs poorly you will improve things with better amp. If it's your room or your speakers that cause the problem a better amp might marginally improve matters. (I heard low-end room problems improve with an amp with a lower output-impedance (higher damping factor for audiophools)). But this is usually not the cheapest way. Better amps usually make the low-end tighter and less boomy but not much louder.

I'm certain that you'll hear a lot of improvement with the UCD's (or one of the other amp-designs in this thread), an you'll probably hear some improvement in the low-end too. But i'm not too sure it will solve your problems. You'll probably need bigger speakers and a larger room for that too.

If you havn't got enough capacitors in your psu it will probably hurt your bass-response. But it's not allways true the other way around. Putting more cap's there only helps if you havn't got enough caps there right now. If it aint broken fixing it will only improve the portability of your wallet.

 

[usekgb]

You could also look at http://www.audiosector.com/ and look at Peter Daniel's LM4780 kits. They put out quite a bit of power for how small they are, and they sound quite good. If you need lots of power, run two of the paralelled LM4780 kits in a bridged configuration. This will supply you with plenty of current and still maintain good control of the speaker in the low frequencies. Also, they are very affordable. Peter's PCB's are top quality and he also supplies all of the necessary parts required to build your amp. While you're there, check out some of the amps he has built. It is truely amazing work!.

Cheers,
Zach

 

[bcarso]

It's reassuring to hear about some sonic results with the UcD stuff, as I find Bruno Putzeys' conception to be compelling (using the output filter as an integral part of the PWM system)---basically taking a serious problem with class D and turning it to one's advantage. There are other ways to get there, some of which are patent-protected, but this one seems elegant. OTOH I haven't heard it yet.

One disadvantage: a multichannel system with nearly identical amps may have heterodyne (beat frequency) artifacts due to the near- but not exactly-same operating frequencies. One can envision ways to correct this but they tend to destroy the simplicity of the approach.

Another strategy is just to space the operating frequencies far enough apart so that the difference frequencies are well out of the audio range. Then be careful not to let the contamination get into sampled-data systems where they can be demodulated again.

Big phat no-holds-barred class A or AB is still probably best sounding, but oh the pain.

 

[rotation]

Samuel: That amp is capable of max 40W (with modification) into 8ohms. I need more sometimes.

Peter C: That are excellent amps for "hi-fi" listening. But problem is that they make bad records sound good. I don't want this. I tried Krell and something similar to Pass Labs. Another problem is their price.

Other menioned gainclone; they are more or less ok for biamping, but when used as normal amps they don't sound good to me. DIscrete designs are much better to my ears. I'm sure about it because i made lots of listening sessions with both designs.

Mendelt:Thanks for clearing out problem with PSU capacitor. I had enough of them, i asked because people at Diyaudio said that more would improve bass response.
In that forum i find strange answers very often. I think that forum is good for hi-fi and audiophile scene, but not for professionals.

I will probably buy the Hypex UCD modules for amp. Second thing will be adding an woofer because pseakers have good bass response only down to 52Hz. I think that's the problem. How others solved this? Also with sub?

Thanks!
Miha

 

[josan]

Built an Elliot Sound Products Kit (the mosfet low power version ) and was very satisfied, excellent detail and very good bass response even though
I use it on Haflers m5. Got lucky with the toroid so total cost was about
150 dollars US. Another interesting amp for low end http://www.41hz.com/
but I have not had any experience with them

Joe

 

[kvintus]

[quote author="Samuel Groner"]If I'd want to build my own amp without designing anything I'd probably go for a design by D. Self. You can get PCBs and kits from: www.signaltransfer.freeuk.com

Have a look at the "Trimodal Power Amplifier".

Samuel[/quote]

Thank you for that link, Samuel! I hadn't seen that one before. Do you have any experience dealing with these guys?


/Anders

 

[Guest]

[quote author="kvintus"][quote author="Samuel Groner"]If I'd want to build my own amp without designing anything I'd probably go for a design by D. Self. You can get PCBs and kits from: www.signaltransfer.freeuk.com

Have a look at the "Trimodal Power Amplifier".

Samuel[/quote]

Thank you for that link, Samuel! I hadn't seen that one before. Do you have any experience dealing with these guys?


/Anders[/quote]
Isn't that the Gareth who posts around on this forum???

 

[Samuel Groner]

Do you have any experience dealing with these guys?

No. I found an add in one of D. Self's books and there is a link on his webpage as well.

Samuel

 

[rotation]

[quote author="josan"]Built an Elliot Sound Products Kit (the mosfet low power version ) and was very satisfied, excellent detail and very good bass response even though
I use it on Haflers m5. Got lucky with the toroid so total cost was about
150 dollars US. Another interesting amp for low end http://www.41hz.com/
but I have not had any experience with them

Joe[/quote]

Do you mean P101? I was thinking a lot about this amp. Lots of fiends done it. They say it's ok, but not very good, at least not for reference. And 2sk1058 mosfets are expensive and difficult to get here.

I'm still thinking of buying the Hypex UCD 180 modules. Anyone here knows its sound well? Any comment would be more than welcome. Btw, i'm still waiting to do some listening tests. Guy is on a vacation now..
Thanks
Miha

 

[bcarso]

I am doing some speculative work when time permits with a highish-end guy and we are about to get some of the 180 modules. The company that has gotten some audiophile press on their amp, Channel Islands Audio, claims somewhere that the 400 is a "much better amp" but I gather has gotten good results out of the 180 when the power supply is done carefully.

 

[rotation]

Hi!
Why did you choose this amp? Did you hear it?

 

[bcarso]

[quote author="rotation"]Hi!
Why did you choose this amp? Did you hear it?[/quote]

No. I like the inventor's idea. With the exception of the much different opposed current amp designs used by Crown, which have several advantages but are off limits due to patents, Putzeys' idea of making the output filter an integral part of the pulse width modulation scheme appeals to me.

I hope to hear one in a suitably revealing system sometime. At the moment I have to rely on the reports from those for whom I have various levels of trust.