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percy 8th October 2004 07:53 PM

Good ~100W amplifier
What is a good high power (~100W range) amplifier kit/design to consider for building one for listening to music and maybe some HT.

From what I have searched so far looks like the ones that would work for me are (in random order) -

Randy Slone's Optimos
Rod Elliott's P3A or 101
Hugh Dean's AKSA 55 or 100 (although this appears to be over my budget I am not ruling these out as yet).
Gainclone LM3875 or LM4780.

Power is not very critical. If there is a good amp that is 50W or 200W I'd gladly consider it. But of ultimate importance to me is the "Sound" of the amp. Stellar specs have failed to please me so far.
Any others out there that I can consider ?

BobEllis 8th October 2004 08:24 PM

Add the Leach amp to your list to consider. I like mine a lot. - plenty of detail, effortless sounding. Prof Leach has the boards and it is relatively straight forward to stuff them. This was my first amp project, although I had built some things before.

If you can cope with the heat, head over to the Pass Labs forum and find yourself a nice class A amp. Count on 2-3 times your output power in waste heat all of the time. I built an A-75 that I like a better than the Leach - it's a little smoother on top and has a better soundstage. You may find that Class A operation is the key to what you've found lacking in super spec amps.

Greg Erskine 8th October 2004 08:30 PM

Re: Good ~100W amplifier

Originally posted by percy
From what I have searched so far looks like the ones that would work for me are (in random order) -

Randy Slone's Optimos
Rod Elliott's P3A or 101
Hugh Dean's AKSA 55 or 100 (although this appears to be over my budget I am not ruling these out as yet).
Gainclone LM3875 or LM4780.

Hi percy,

There are lots of very good amps and you would probably be happy with most of them, especailly when you build them yourself.

However, from your list I have built:

Rod Elliott's P3A
Hugh Dean's AKSA 55 (standard)
Gainclone LM3875

All are good amps but I have a definite preference for the AKSA. It makes me :D

It really comes down to your budget. I would buy a standard AKSA 55 (and get the Nirvana and Nirvana+ updgrade when funds are available) for the main speakers and Gainclone's for the rest. I have built a few of BrianGT NIGCs and can recommend them if you don't like doing point to point wiring. Get more advice from others about subs.

I believe Rod has upgraded the P3A with a new high quality PCB.

Randy Slone's Optimos would also be a nice amp and I have found his amp design books very easy to read and enjoyable. I must build one after I finish my current projects.

tg3 8th October 2004 08:34 PM

If I wanted to build a discrete amp from scratch with only a premade board, I'd go for Rod Elliott's 101.

If $$ were not a big concern, I'd go for Hugh's AKSA 100 with all the upgrades.

Best bang for the buck without question is the LM4780 kit from BrianGT.

Another one to consider is the UcD 180, a class D amp module distributed in the US by Adire Audio.


ultrachrome 8th October 2004 08:41 PM

I have built the AKSA 55 and the NIGC with LM3875.

The nice thing about the AKSA is everything is included except transformers and enclosure. I chose AKSA over ESP because parts selection and sourcing seemed too daunting for me at the time.

On the other hand, the LM3875 amp is extremly simple and inexpensive.

I also prefer the sound of the AKSA over the LM3875.

acenovelty 8th October 2004 08:44 PM

Gainclones are the most simple to build with little or no adjustment needed.
Consider the Leach amp at:
120W into 8 Ohms. More complicated for a first time amp builder. Documentation on the site is quite extensive tho. Many successful builders out there with variations on the original amp layout.

Remember that you will listen to sound, not specs.
Your speakers will influence how the amp sounds.

lbruynseels 8th October 2004 10:21 PM

No doubt. UCD180 cheap, excellent sonic qualities.

If you want to solder: do a dc protection, power supply, preamp, mixing console, ...

destroyer X 9th October 2004 12:21 AM

One place with live music, two options:
You can heard the music inside the bar, or outside the bar.

If you prefer the "presence" of the music, to have the pleasure hearing and not talking, go to AKSA.

To hear music outside the bar, talking...many options will satisfy.

I like AKSA sound.



percy 9th October 2004 03:40 AM

Thank you all. Your responses will be very useful.

I haven't yet done a cost analysis on the other amps but looks like AKSA might not fit the budget :( .
And the UCD180 does not offer much opportunity of 'building'(aka fun, learning etc..). I believe building is a learning process too.
Well anyway, so assuming AKSA and UCD180 are out (with all due respects to both) the final contenders would be (in random order) -

ESP 101
Gainclone LM4780

Thoughts anyone ?

AKSA 9th October 2004 04:03 AM

Hi Percy,

The AKSA is not so expensive for what you get; all component selections made, pcbs, including power supply pcb, all filter caps, even the heatsink. Only the transformers, case and binding posts are required, and by the time public domain amps are built and functioning, the costs are very similar.

PLUS you get technical backup with the AKSA! From me no less!

However, gainclones are certainly cheaper, and the digital amps require no heatsink. These decisions are always difficult, and good luck in your quest!!

Carlos, Greg, tg3, Ultrachrome, thank you for your favourable comments. Appreciated!



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