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Should I build an First Watt Clone and how do I choose which one?


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I have an excellent integrated amplifier which sounds fantastic but is not really suited to how I use my system. I’m thinking of replacing it with a DAC/Pre and a power amp and have become enamoured with the idea of getting some Nelson Pass into my system. While I would love to be in a position to drive across town and grab a First Watt something off the shelf, my budget (maybe $1200, give or take) dictates a more modest proposal.

 

The clone kits and boards (aleph J, F5, F6, M2X, etc) all seem to be around 25 watts per channel and similarly priced so, how does one choose between them?

 

The other factor is my speakers. I am absolutely not changing them but they are very inefficient at only 86dB/w/m. I know 25W class A is not the same as 25W class AB but I’m open to the possibility that these are just not suited to my speakers. The good news is that they’re nominally 8 ohm and they don’t drop below 7 ohm so they’re not a difficult load per se, they’re just not very efficient..

 

I would appreciate the input of anyone who has advice or direct experience with these amps. If anyone in Melbourne has one that they could live without for a weekend, I’d be grateful for the opportunity to pick it up and drop it back with a nice bottle of red to soothe any potential separation anxiety 😉

Edited by RankStranger
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Have you thought about a Holton based amp? They can drive a John Deer tractor. 500W into 4 and about $1500 to build. 

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4 minutes ago, mwhouston said:

Have you thought about a Holton based amp? They can drive a John Deer tractor. 500W into 4 and about $1500 to build. 


Thanks, Mark. I’ve thought about it and it’s still a possibility. I currently have a 215W class AB integrated and I have run them happily off a 40W Naim super-integrated in the past so it’s not that they need a lot of power. I’m mostly exploring my options, of which Holton is definitely one. 

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Before you decide to listen to any First Watt amp check out which one would be suitable. For an all rounder I'd go F6

 

If you decide to build then don't skimp on the power supply as that'll remain for every FW model you build. As you probably know they all use the same spec PSU.

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I drive a pair of Lenehan LK1 which are 86dB with an M2X absolute breeze for the amp.

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41 minutes ago, Batty said:

I drive a pair of Lenehan LK1 which are 86dB with an M2X absolute breeze for the amp.


thanks, Steve. What made you choose the M2X?

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I have used the F5 - F6 - M2 

 

All are good but for my speakers that are very sensitive the M2 sounds more controlled overall 

The F6 has more grunt and punch though in comparison 

 

I put up a review of the 2 somewhere on the forum 

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31 minutes ago, Full Range said:

I have used the F5 - F6 - M2 

 

All are good but for my speakers that are very sensitive the M2 sounds more controlled overall 

The F6 has more grunt and punch though in comparison 

 

I put up a review of the 2 somewhere on the forum 


did you just build one and then change the board over? It seems that they are mostly the same except for the board

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You could try this one - the PCBs are available from the thread:

Alpha Nirvana 39w 8ohm Class A Amp - diyAudio

 

40w into 8 ohms ... a bit more into 7 ohms.

 

And here's the very special PS:

The SLB (Smooth Like Butter) Active Rect/CRC/Cap Mx Class A Power Supply GB - diyAudio

 

Ideal for your 7 ohm spkrs.

 

I'm just about to finish building 2 of the dual-mono 4 ohm version (to power my 3 ohm mids & 2 ohm ribbons).

 

If you read through the AN thread, several people who had already built the Pass amps mentioned above ... think the Alpha Nirvana sounds better.  :)

 

Andy

 

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49 minutes ago, RankStranger said:


did you just build one and then change the board over? It seems that they are mostly the same except for the board


The F5 was upgraded / rebuilt to the F6 

The M2 was a complete new build 

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Posted (edited)

The other option I have is that I have a half-built gainclone BrianGT LM3886 chipamp that I kind of assumed was pretty crappy but after doing some reading, maybe I should finish building that and see how it sounds first. All it needs is a chassis and maybe some plugs. There’s a bunch of ok-looking chassis on aliexpress that would work. 
 

I know it’s not going to sound as good as a Pass design but it might do for the meantime. Anyone used one?

Edited by RankStranger
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On 07/03/2021 at 8:51 AM, RankStranger said:


thanks, Steve. What made you choose the M2X?

I chose it because of the choice of input buffers.

I also used a larger transformer, recommended was 300 VA, I used a 360 VA, only because the price difference was about $25.

Bigger PSU is always good. Mine was tested to be almost 40 watts into 4 ohms too.

Edited by Batty
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16 hours ago, RankStranger said:

I know 25W class A is not the same as 25W class AB

 

What do you mean?   

 

16 hours ago, RankStranger said:

but I’m open to the possibility that these are just not suited to my speakers. The good news is that they’re nominally 8 ohm and they don’t drop below 7 ohm so they’re not a difficult load per se, they’re just not very efficient..

 

It depends on how loud you play your speakers (which is why you will get a whole spectrum of "opinions" on this).   Every 3dB louder is double the amplifier power required..... and the difference between one persons "normal volume",  or "loud" and another persons might be very different..... so one mans 4 watts needed might be anothers, 40watts.... might be anothers 400watts.

 

Also, different amplifiers clip very differently.   FW amplifiers are designed to clip "gracefully" ..... so people may be driving their (relatively) low power amplifiers into clipping, but not be able to hear it.

 

 

One thing to know with the FW amplifiers is they're all very different.  The ones you named are all "normal" enough amps.... but some of them are quite "abnormal" designs in that they have low gain, and/or high output impedance, so won't be suitable to many systems.

 

 

16 hours ago, RankStranger said:

 

I would appreciate the input of anyone who has advice or direct experience with these amps. If anyone in Melbourne has one that they could live without for a weekend, I’d be grateful for the opportunity to pick it up and drop it back with a nice bottle of red to soothe any potential separation anxiety 😉

 

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17 hours ago, davewantsmoore said:

What do you mean?


sorry, I missed this question. The only class A amp I’ve spent any time with - and it wasn’t a lot - was the Audio Analogue Maestro Class A which was 50 wpc and it did things I’ve never heard any other ss 50 wpc amp do. I assumed it was because it was class A - something to do with how it’s always on power is how I understand it - but always happy to be further educated :) 

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5 hours ago, RankStranger said:


sorry, I missed this question. The only class A amp I’ve spent any time with - and it wasn’t a lot - was the Audio Analogue Maestro Class A which was 50 wpc and it did things I’ve never heard any other ss 50 wpc amp do. I assumed it was because it was class A - something to do with how it’s always on power is how I understand it - but always happy to be further educated :) 

 

1 watt is 1 watt.

 

Amplifiers all clip differently (sound different) when you drive into full power .....  but that's obviously not recommended

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The power measurements are a bit fudgy and averaged anyway, all amps behave a little differently with different loads. Remember an 8ohm speaker is only 8 ohms sometimes, usually with a big spike in the punchy 60-100hz bass region, so an amp that can handle lower impedances will sound stronger than one that either can't do it, or has different distortions under stress.

 

Nelson himself said the F series (i think he was referring to the F7) were more neutral and a good allrounder, and the one he would recommend to most people.

 

Watch out for the cheaper clones, as they use poor quality parts, but the PCBs are usually fine, just get real transistors and decent caps and you'll be fine.

Edited by GaryT
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  • 2 weeks later...
On 07/03/2021 at 1:02 PM, RankStranger said:

The other option I have is that I have a half-built gainclone BrianGT LM3886 chipamp that I kind of assumed was pretty crappy but after doing some reading, maybe I should finish building that and see how it sounds first. All it needs is a chassis and maybe some plugs. There’s a bunch of ok-looking chassis on aliexpress that would work. 
 

I know it’s not going to sound as good as a Pass design but it might do for the meantime. Anyone used one?

I had a chip amp for a while and to be honest they are not that great. The FW amps are in a totally different league.

Edited by Gryffles
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36 minutes ago, Gryffles said:

I had a chip amp for a while and to be honest they are not that great. The FW amps are in a totally different league.

 

Thanks, Ben. Yeah, I finished it and it’s... adequate. I’m building a case for it and I’ll use it in the meantime, probably while I build an F6 or something like that. It just takes a bit of the pressure off to decide and saves me from having to buy something to use and then resell it. 

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29 minutes ago, RankStranger said:

 

Thanks, Ben. Yeah, I finished it and it’s... adequate. I’m building a case for it and I’ll use it in the meantime, probably while I build an F6 or something like that. It just takes a bit of the pressure off to decide and saves me from having to buy something to use and then resell it. 

Your thoughts match mine......they're adequate! I get it mate and sounds like a good idea and similar to my purpose for a chip amp.

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Love my M2X

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The Aleph J I have though like others mentioned runs 25 watts at 8 ohms it dips to 14 watts into 4 ohms.

Its quite happy running MG 1.5`s, 85dB, 4 ohms or Infinity RS4b`s 87 dB (I think) at 4-8 ohms. 

The pre is a tube kit. The volume knob sits from about 25% to 35% depending on source. The thing I cannot remember is whether its a log or linear pot. I was into linear pots when I started now its log pots so in might be a few % higher.

Room size to me is the big one. The two rooms I use are 3x4 or 4x5m and I don`t listen at extremely high levels.  

 

Tony

 

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Referring to Steve's post above (Batty - Mar 7) about choosing the M2X amp for the selection of input stages, these same input stages can be used in the F6 too, although these pcbs are designed to fit snuggly onto the M2x pcb and require some 'links' to fit the F6 layout but the original input stages on both amps are simple jfet buffers and Mark Johnson has developed a family of optional buffers to experiment with - the sound of the M2x and the F6 are a bit different mainly due to the different signal transformers and the feedback design.

 

The F6 appeared about 10 years ago and became a diyA project in 2014, I think - the M2x appeared a few years after that and was designed for a different end-use and price - it as a more "SET" type sound (a bit 'softer' sound, perhaps).

 

One thing also that's common to both these amps is not only the bigger mains transformer that Steve mentioned but the power supply itself including those relatively new synchronous bridge rectifiers based around the LT 4320 chip,  and the Capacitor Multiplier filters or even Salas' L-Adapter regulator circuit - these transform an already rather good amplifier to an excellent one, well worth the trouble and cost if it suits your speakers/room/taste.

 

I was quite surprised by Tom Christianson's Neurochrome  version of the LM3886 'gainclone' amps - I tried the basic version (30W/8R) and stayed with the recommended Bill of Materials, it produced a highly detailed sound that was also rather 'fast' - gave the impression of not having a sound at all - nearly totally transparent and no 'fatigue' - rather remarkable actually.  Not my 'cup-of-tea' but seems to mate up well with those 10" FR drivers from Lii Audio.

 

 

 

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