Hi All,
I've been itching to build a Nelson Pass amp for a couple of years now, but I'm hesitant to pull the trigger on any particular kit since I'm new to this and have limited time and budget to try them all (though am not all that new to electronics). I also may need a reality check to know if any of the current offerings will even meet my needs. I've never heard any of these in person, nor any low watt class A amps. So, not exactly sure what to expect. I'm hoping you could help me pick an amp that'll fit my needs, or maybe even dissuade me if in fact none of them will meet my needs. I just really like the idea of building a world-class type amp with my own hands.
A little background. I currently have a home theater setup with Elac towers (~87db sensitivity, 6-ohm nominal) that I'm looking to pre-out the front channels to a higher fidelity amplifier. My primary music source is through Raspberry Pi -> USB DAC. This setup would be temporary, as I hope to build a dedicated 2-channel system in another room of the house in a couple of years, using the newly built amp and high-sensitivity DIY speakers that I also hope to build in the future. The HT receiver does have an SVS sealed sub, in case that matters.
Music and preferences
My primary listening habits include classic rock (Pink Floyd, Rush, Led Zep, Police, Dire Straits), and electronic/post rock/alternative/indie (Kraftwerk, Foster the People, Mutemath). I sometimes listen to other acoustic stuff like folk and jazz.
Preferred sound signatures: airy, detailed, wide soundstage, clear instrument separation, black backgrounds, great imaging. Somewhat forward and fun without being fatiguing, forward vocals and midrange, with slam and presence. Warmth, but not muddy - just a little bit lush.
I don't listen at extreme loud levels, but maybe a "comfortable" loud that will fill a 17x17 open room with sound - comfortable loud as in too loud to carry on a conversation with someone in the room, but not so loud that it is uncomfortable to sustain for more than a couple of songs. Are the Pass builds the way to go for me? If so, which one would you suggest, given my music choices and listening preferences?
Thanks!
Thad
I've been itching to build a Nelson Pass amp for a couple of years now, but I'm hesitant to pull the trigger on any particular kit since I'm new to this and have limited time and budget to try them all (though am not all that new to electronics). I also may need a reality check to know if any of the current offerings will even meet my needs. I've never heard any of these in person, nor any low watt class A amps. So, not exactly sure what to expect. I'm hoping you could help me pick an amp that'll fit my needs, or maybe even dissuade me if in fact none of them will meet my needs. I just really like the idea of building a world-class type amp with my own hands.
A little background. I currently have a home theater setup with Elac towers (~87db sensitivity, 6-ohm nominal) that I'm looking to pre-out the front channels to a higher fidelity amplifier. My primary music source is through Raspberry Pi -> USB DAC. This setup would be temporary, as I hope to build a dedicated 2-channel system in another room of the house in a couple of years, using the newly built amp and high-sensitivity DIY speakers that I also hope to build in the future. The HT receiver does have an SVS sealed sub, in case that matters.
Music and preferences
My primary listening habits include classic rock (Pink Floyd, Rush, Led Zep, Police, Dire Straits), and electronic/post rock/alternative/indie (Kraftwerk, Foster the People, Mutemath). I sometimes listen to other acoustic stuff like folk and jazz.
Preferred sound signatures: airy, detailed, wide soundstage, clear instrument separation, black backgrounds, great imaging. Somewhat forward and fun without being fatiguing, forward vocals and midrange, with slam and presence. Warmth, but not muddy - just a little bit lush.
I don't listen at extreme loud levels, but maybe a "comfortable" loud that will fill a 17x17 open room with sound - comfortable loud as in too loud to carry on a conversation with someone in the room, but not so loud that it is uncomfortable to sustain for more than a couple of songs. Are the Pass builds the way to go for me? If so, which one would you suggest, given my music choices and listening preferences?
Thanks!
Thad
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>F6 would be another great option to consider.<
Yes F6 together with B1Triode Korg preamp.
AlephJ amplifier if audio source with balanced outputs 🙂
Yes F6 together with B1Triode Korg preamp.
AlephJ amplifier if audio source with balanced outputs 🙂
I would say the M2x it has the five daughter boards to play with . All nice just a slight sonic difference that may give a more tailored sound to match your speaker set up. My 2 cents...
One thing I was concerned about, but don't have a lot of experience in, is the voltage gain of these amps being a bit lower than most. Would a HT Receiver have a hard time driving these? I have a newish Denon Receiver.
For the most part, I've narrowed my search to the F6, M2x, and BA-3. I'm slightly leaning towards the BA-3 with 30v rails, but think it may be more difficult than the others? It also seems to have a 30db voltage gain, which I understand might be more forgiving of source. Though, I'm not very knowledgable at all on this, so please let me know if I'm mistaken here.
Considering what I'm looking for, would you consider any of these to stick out more than the others? Any I should stay away from since it'll be my first build?
Thank you all so much for your advise and feedback.
Considering what I'm looking for, would you consider any of these to stick out more than the others? Any I should stay away from since it'll be my first build?
Thank you all so much for your advise and feedback.
F6, M2, F5
BA2 hardly ever gets mentioned but that is a very fine amp too.
There's BA3 also, but BA2 gets you close to something like a J2/Aleph J but with a push pull output stage, without needing to make tonal adjustments which BA3 requires.
BA2 hardly ever gets mentioned but that is a very fine amp too.
There's BA3 also, but BA2 gets you close to something like a J2/Aleph J but with a push pull output stage, without needing to make tonal adjustments which BA3 requires.
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The BA-3 with higher voltage rails is not too hard, and you can follow the build guide exactly for it. The matched transistors required are available from the store, so no problems there. I can't say if it sounds better than F6 or M2x but it does sound really good.
I think if you ask 100 people you will get 100 different responses. 🙂 I've built several of the First Watt amps. I have medium efficiency speakers (87db) with a pretty steady 6ohm impedance. My rankings in order of preference:
(1) F4
(2) F5/F5T
(3) BA-3/BA-2
(4) F6/AlephJ
(5) M2
When I first started researching these amps I thought the F6 and M2 would be my favorites since I have own tube amps almost exclusively. Oddly, those two ended up being my least favorites. I've since given the F6 to a friend and used the chassis and power supply from the M2 to build other amps. Given how much I like the F4 and F5 I also thought the BA-3 would be a logical choice since it is said to provide the best of both. However, I liked both the F4 and F5 better than the BA-3 (while it does have traits of each, for me it loses a bit of what makes each of those amps unique and special). I have kept the F4, F5 and F5T and rotate them every month or so along with my tube amps.
(1) F4
(2) F5/F5T
(3) BA-3/BA-2
(4) F6/AlephJ
(5) M2
When I first started researching these amps I thought the F6 and M2 would be my favorites since I have own tube amps almost exclusively. Oddly, those two ended up being my least favorites. I've since given the F6 to a friend and used the chassis and power supply from the M2 to build other amps. Given how much I like the F4 and F5 I also thought the BA-3 would be a logical choice since it is said to provide the best of both. However, I liked both the F4 and F5 better than the BA-3 (while it does have traits of each, for me it loses a bit of what makes each of those amps unique and special). I have kept the F4, F5 and F5T and rotate them every month or so along with my tube amps.
I would also vote for F4, although he might need to add a preamp so that is potentially more work.
Based on your skills and future DIY of more sensitive speakers, try the ACA kit.
Also, with the ACA platform, if you like it, you could build another amp kit and bridge them for more power. Two ACA kits would cost a little more than one M2, F6, etc.
I use a lower power ACA (19v supply, 4W output) to drive 86db 6 ohm speakers. The sound is smooth, detailed and engaging. ACA seems more powerful than its power rating suggests.
Just a thought. Good luck with whatever you choose.
Also, with the ACA platform, if you like it, you could build another amp kit and bridge them for more power. Two ACA kits would cost a little more than one M2, F6, etc.
I use a lower power ACA (19v supply, 4W output) to drive 86db 6 ohm speakers. The sound is smooth, detailed and engaging. ACA seems more powerful than its power rating suggests.
Just a thought. Good luck with whatever you choose.
With the F4, your possibilities broaden a bit.
Whatever high-gain preamp you put in front of it, the F4 will pass on the preamp's sound with power. Read the F4 manual at firstwatt.com
You could do the same with the MoFo. Another great amp and super simple.
Whatever high-gain preamp you put in front of it, the F4 will pass on the preamp's sound with power. Read the F4 manual at firstwatt.com
You could do the same with the MoFo. Another great amp and super simple.
ACA is one of my favorite amps (possibly most favourite) on the right speakers.
If you biased it to 2A it would probably work.
Or you do parallel mono.
If you biased it to 2A it would probably work.
Or you do parallel mono.
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once he starts building, he will not be able to stop
he should build most of them and compare
or just do F4 and a dozen of preamps, that may be cheaper
he should build most of them and compare
or just do F4 and a dozen of preamps, that may be cheaper
He is definitely not going to stop at one.
Most logical choice is F4 followed by a stack of different preamp topologies.
Most logical choice is F4 followed by a stack of different preamp topologies.
Oh, my head is spinning now. You all are probably right. I will likely end up building all of them. �� The F4 definitely does sound like an interesting approach. Though not speaking from experience, I suspect I would enjoy an amp with no feedback and push-pull output (given the complexity of music I listen to). Given my current AVR as a preamp situation, though, would you recommend a separate and simple gain stage for the F4?