DIY Deathmatch: SET vs SS Class A

Bottlehead Stereomour vs First Watt F5/B1

Well, I wasn't really sure where to put this, but being as the two designs are at the fringe of SS and Tube, I thought that the cutting edge was appropriate. That and I've been itching to play here. :D

So, as some of you know, I recently took the plunge into SET and bought a Bottlehead Stereomour. Well, I think I have had enough time listening to both amplifiers through my Altec Model 19's at this point to begin to draw some conclusions.

These two amplifiers sound alot more similar than they do different, but I will be focusing on what little differences exist.

1. Presence. I don't know exactly what the word I am looking for here, but I guess presence will have to work. The Bottlehead has just a little more "they are here" to it than the F5.

2. Bass. This one goes to the F5, hands down. Thats not to say that the SET design is lacking in bass, but the F5 delivers some of the cleanest most extended bass I have ever heard.

3. Midrange. This is nearly a dead heat between the two. Both are truly beautiful in the midrange but the Bottlehead is just a hint sweeter with the F5 being a hint more neutral. Depending on one's taste, this could easily go either way. For me, I prefer the sweetness of the Bottlehead.

4. Imagaing. This again was close but there is a noticeable difference with the Bottlehead providing a slightly larger and more lush soundstage.

Winner: Bottlehead Stereomour, although as Specialidiot told me before I started this adventure, I could easily see myself using one for six months and then switching back to the other for six months. They are both very, very nice amplifiers and I feel blessed to own them. I'm sure I'll have more to add after more listening but this is what I have noticed so far...
 
Bottlehead Stereomour vs First Watt F5/B1

Well, I wasn't really sure where to put this, but being as the two designs are at the fringe of SS and Tube, I thought that the cutting edge was appropriate. That and I've been itching to play here. :D

I'm glad you decided to join us here, and I think this is absolutely the right place to post it. I enjoyed reading your impressions, and also I appreciate that you just came out and said which one you prefer, which I sometimes note people are hesitant to do about audio equipment, fearing they could end up being held to some contractual obligation and unable to change their mind at a later date. :)

I have a pair of Bottlehead Paramours that are basically built, but, let's say, in stasis for a number of reasons irrelevant in this thread. When I finally get them up and running I'll likely start a similar thread in this forum.

EDIT: Another thought - have you considered modifying/upgrading your Stereomour in any way? As you no doubt know, few amps are more ripe for that sort of thing than Bottleheads.
Did you build it from the kit or buy it second-hand?
 
I'm glad you decided to join us here, and I think this is absolutely the right place to post it. I enjoyed reading your impressions, and also I appreciate that you just came out and said which one you prefer, which I sometimes note people are hesitant to do about audio equipment, fearing they could end up being held to some contractual obligation and unable to change their mind at a later date. :)

I have a pair of Bottlehead Paramours that are basically built, but, let's say, in stasis for a number of reasons irrelevant in this thread. When I finally get them up and running I'll likely start a similar thread in this forum.

EDIT: Another thought - have you considered modifying/upgrading your Stereomour in any way? As you no doubt know, few amps are more ripe for that sort of thing than Bottleheads.
Did you build it from the kit or buy it second-hand?

I built my Bottlehead from a kit in bone stock configuration. At some point I may consider upgrading the poly caps in it but to be honest the stock caps are solens which I have used in several projects, including the Z19 crossovers in my Altecs and really like them. We shall see what the future holds. For now I am building a Seduction to go with my Stereomour.
 
Isn't it a blast to build them?

Sorry to go a bit off-topic here, but did you build the Cornet2 as well?
 
Great post Anthony; exactly what this forum is all about and these 2 amp approaches are sure different takes on getting the most out of your system.

Nice to read your findings here as I’ve wanted to do this kind of direct comparison in my system as well – I’m a huge fan of low power SET amps (especially 2A3) but find the Pass SS approach very intriguing. I guess what I’m hoping for is all I love about SETs (or at least most of it) in a reliable, plug-and-play SS package that betters SETs in the bass, and it sounds like that is exactly what you found in the F5.

The ‘presence’ trick you speak of is the thing that really shocked me with SET the first time I heard one (a 300B amp which can be scary good with midrange presence) and a trait I have been hooked on for about 10yrs now. I’ve heard systems and tried other approaches that beat out SETs in other areas but this is the strength I keep coming back to – the ability of a good SET amp (with the right speakers) to float a flesh-and-blood image in the room that sucks you into the music and lets you forget about all the audio ‘stuff’.

The deep bass is certainly the weak point in most SETs I’ve heard and even though it can be very good, I’ve just never heard the solid bottom-end from my Altecs on SETs that I hear with a SS amp or good push-pull tube amp with feedback. I do like the bass from a tube like the 2A3 – especially on natural instruments like upright bass where the tone and presence can be so ‘real’ sounding – but listening to some heavy rock can show some warts. Good output transformers, power-supply design, component mix and (especially) speaker matching can mostly eliminate the bass issue but I suspect the best way is to integrate a SS sub-bass system – let the SETs do what they do well for 95% of the range and use SS grip and muscle below that.

I don’t remember seeing a schematic for the Stereomour (is it capacitor coupled?) but suspect there are lots of opportunities to push its performance higher and flavor-to-suit. Example; I know with my 300B, 2A3 and 45 builds I regularly used coupling caps to tailor the sound to get a mix I liked with the rest of my system. Since these circuits are so clean and simple, tweaking can be fun and inexpensive with sometimes immediate and surprising results all the way to the speakers (think thin speaker ‘wire’ instead of ‘cables’ :)).
 
Since these circuits are so clean and simple, tweaking can be fun and inexpensive with sometimes immediate and surprising results all the way to the speakers (think thin speaker ‘wire’ instead of ‘cables’ :)).

Im a fan of thin wire on my SE amps as well. On my 6B4Gs, I use 20AWG thermostat wire, while on the EL84s, Im using 22AWG intercom wire. Cat5 is great stuff too :yes:
 
Not to discount Billfort's SET vs. SE SS comment on bass... I think the Stereomour would be at a somewhat artifactual disadvantge in LF extension/linearity given its rather modest output transformers (i.e., I think other SETs might bring a little more game to this particular parameter).

Just sayin'.

EDIT: I assume that the Stereomour, like the earlier Paramour monoblocks, uses a parellel-feed output topology... yes/no/maybe?
 
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First off, great post. I've heard Pass gear but never the single ended low power Aleph stuff. I'd love to hear it one day and do exactly what you did here with my DIY SET amp.

The ‘presence’ trick you speak of is the thing that really shocked me with SET the first time I heard one (a 300B amp which can be scary good with midrange presence) and a trait I have been hooked on for about 10yrs now. I’ve heard systems and tried other approaches that beat out SETs in other areas but this is the strength I keep coming back to – the ability of a good SET amp (with the right speakers) to float a flesh-and-blood image in the room that sucks you into the music and lets you forget about all the audio ‘stuff’.
Could not agree more. I've had some gear that did a lot of things better than my SET, and I've heard some gear that does a lot of things better then my SET. But I always miss that one special thing that my SET does, I've never heard it outside of a SET amp. Hard for me to describe.

Not to discount Billfort's SET vs. SE SS comment on bass... I think the Stereomour would be at a somewhat artifactual disadvantge in LF extension/linearity given its rather modest output transformers (i.e., I think other SETs might bring a little more game to this particular parameter)
I ran my SET with some decent OPTs for a couple of years. Then a friend suggested I try his Electraprint monsters, not sure of the model. The difference was night and day, like another amp. Mostly in the bass but top to bottom. It would be hard for me to overstate the difference. I bought the EPs from him and I run them now.
 
The SET amps, as some waggish audiophiles like to put it, "lift a veil" on the music. It's a pretty striking phenomenon. I expect that the PASSLabs SE amps can do most of it, too - the thing about triodes, though, is that they're danged linear amplifying devices.
 
Great post in TOL, thanks. This is the kind of thing I really enjoy....learning about gear other than my own.
Sounds like "death match " might end up as another poster said and you'll use both in rotation, more like an ongoing wrestling match.
Altec Model 19's, nice!:music:
 
Oh I agree Mark and sebrof, output transformers make a huge difference in the bass with SETs, everywhere actually - I think OTs might be the most important part of these simple amps.

I really like James iron and ElectraPrint (which I've used for 300Bs) but some of the best SETs I've heard used Tango - even though ElectraPrint might have outdone the Tango in the bass.
 
Aah, but can your SET do this ?

Besides being able to drive two or more pair of headphones at the same time, the Taboo MKIII can also drive loudspeakers or loudspeakers and headphones at the same time.

Steve has NEVER been shy about blowing his own horn :D

taboosm2.jpg
 
The best sounding LF (both qty. and quality) on my bass horns was achieved using a SET 45 amp. I love my 2A3 amps but was stunned by the LF with the 45.

I've owned or listened to many Class A amps (true Class A amps) also and like many of them. I'm a tube guy but if I was looking to run over 15-20w it would be Class A all day long.

RC
 
I kind of agree - the 45 IS all that...but 1.5wpc?

Speakers, speakers, speakers and my Altecs (and Anthony's) aren't going to cut it with 1.5w.

Just my experience you understand. :)
 
I kind of agree - the 45 IS all that...but 1.5wpc?

Speakers, speakers, speakers and my Altecs (and Anthony's) aren't going to cut it with 1.5w.

Just my experience you understand. :)

Yeah, I have to agree about the 45's. I feel like 2A3 is about the lowest wattage I can live with. Never heard a 45 though, if I had the right speakers, who knows. The Stereomour can easily be converted to run 45's...

What I'm really thinking of doing is keeping the Altecs with the Bottlehead and starting a new system for the Pass stuff... Tekton speakers look interesting....
 
Great post Anthony; exactly what this forum is all about and these 2 amp approaches are sure different takes on getting the most out of your system.

Nice to read your findings here as I’ve wanted to do this kind of direct comparison in my system as well – I’m a huge fan of low power SET amps (especially 2A3) but find the Pass SS approach very intriguing. I guess what I’m hoping for is all I love about SETs (or at least most of it) in a reliable, plug-and-play SS package that betters SETs in the bass, and it sounds like that is exactly what you found in the F5.

The ‘presence’ trick you speak of is the thing that really shocked me with SET the first time I heard one (a 300B amp which can be scary good with midrange presence) and a trait I have been hooked on for about 10yrs now. I’ve heard systems and tried other approaches that beat out SETs in other areas but this is the strength I keep coming back to – the ability of a good SET amp (with the right speakers) to float a flesh-and-blood image in the room that sucks you into the music and lets you forget about all the audio ‘stuff’.

The deep bass is certainly the weak point in most SETs I’ve heard and even though it can be very good, I’ve just never heard the solid bottom-end from my Altecs on SETs that I hear with a SS amp or good push-pull tube amp with feedback. I do like the bass from a tube like the 2A3 – especially on natural instruments like upright bass where the tone and presence can be so ‘real’ sounding – but listening to some heavy rock can show some warts. Good output transformers, power-supply design, component mix and (especially) speaker matching can mostly eliminate the bass issue but I suspect the best way is to integrate a SS sub-bass system – let the SETs do what they do well for 95% of the range and use SS grip and muscle below that.

I don’t remember seeing a schematic for the Stereomour (is it capacitor coupled?) but suspect there are lots of opportunities to push its performance higher and flavor-to-suit. Example; I know with my 300B, 2A3 and 45 builds I regularly used coupling caps to tailor the sound to get a mix I liked with the rest of my system. Since these circuits are so clean and simple, tweaking can be fun and inexpensive with sometimes immediate and surprising results all the way to the speakers (think thin speaker ‘wire’ instead of ‘cables’ :)).

Thin wire? Hmmm... Never even imagined it. Seems that could be another fun place to play. Right now I'm using some thick Audio Art biwire cables.
 
Isn't it a blast to build them?

Sorry to go a bit off-topic here, but did you build the Cornet2 as well?

Sure did. It's an outstanding phono pre but I've got a little hum in mine i need to get sorted out. It's not audible when music is playing but I know its there and that annoys me to the point that I need to do something about it. I'll be opening it up soon...
 
For shits and giggles, tear a single twisted pair out of some CAT5 network cable and give it a shot - might surprise you. With what's left, spin a braid where you are using 3 wire pairs (3+/3-) and try that - might surprise you even more and may have you going back to the single pair.

This is fun stuff and what works with low power SETs is often not what audiophile conventional wisdom dictates.
 
or some fine-gauge (pick your poison), enamel-insulated copper magnet wire - livin' large! :) ... or not-so-fine. My "real" speaker cables, courtesy of none other than "Cableguy" Bill, are, as far as I can tell, a twisted pair of 12-ga enamel (or varnish?) insulated magnet wire - and they are fine. Very fine.
 
I kind of agree - the 45 IS all that...but 1.5wpc?

Speakers, speakers, speakers and my Altecs (and Anthony's) aren't going to cut it with 1.5w.

Just my experience you understand. :)


No disagreement here, Bill. Just commenting on my amazement with the 45's ability to stomp the higher powered 2A3 in terms of LF weight and impact.

In my room and with much of what I listen to, I'm on the edge of being able to pull off 45's without much reservation on my part. I may just end up there.

RC
 
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