Low power output triodes

[bumpy]

I know very well the attributes of SE 300Bs and 2A3s, but what of the valves with even lower output such as the 45, PX25 and others.

Assuming very sensitive speakers, what are the attributes of these other valves. This is primarily about SQ, but could include cost of building the amps (size of transformers, high voltage needs etc) and even cost of the valves themselves.

Thanks

[danilo]

Had a meshplate Se 45 Amp gizmo. A Bespoke unit
It was OK.. Used it for a year or so.
Had to... Or Wife would have Killed me :eyebrows:
To MY mind Nothing near the value I paid though.
Iffy dynamics, some quite nice detail sounds.. but I never did fall in love with it.
Like a lot of things in my life; the Wanting proved better than the Having.

G'luck

[bumpy]

Had a meshplate Se 45 Amp gizmo. A Bespoke unit
It was OK.. Used it for a year or so.
Had to... Or Wife would have Killed me :eyebrows:
To MY mind Nothing near the value I paid though.
Iffy dynamics, some quite nice detail sounds.. but I never did fall in love with it.
Like a lot of things in my life; the Wanting proved better than the Having.

G'luck

Strange, I have heard this sort of comment before with 45 amps. I guess an audition in your own system is all important with non mainstream amps like this. What speakers did you run them with?

[paulf-2007]

A 45 into the right speaker is magic, depending on the quality and design. I've had 300B and 2A3 into lowthers and compression driven front horns, both very good. I now have PX25 into Zu Omen, amps were built by Jim Turner for Jim Carfrae to demo his Carfrae horns at shows. Into a lowther at 99db they need to run very quietly and these are silent but take an hour to warm up.

[SPS]

On normal ish speakers these valves dont alway reveal what they are capable of,
and the valves themselves vary with age and the specific build, generally the older valves sound better.

With these low power valves the quality of the speakers is critical as is the way the amp is designed and made along with the quality of the components
The 2a3 was the american version of the british px4, but really not quite as good, the early monoplate are better and fetch high prices but the dual anode, more common version is not quite so nice sounding but on the level of of some of the better new production.
The trouble is that on many amps the older valves generally reveal more and regularly show up short comings in the amp or speakers and are blamed for that ....
Some of the new production px25's are quite good, at the level of the late production GEC straight sided.
The earlier globes are better in my view by a margin.
45's are nice valves, the valve itself does not pruduce the bass of a px4 or 25, in my view the british valves is quite something with the right speakers, but with the right speakers and in a good amp can give a nice sound.
If you diying there are lots of older ( pre war) British valves that can give a really good sound on a budget
If your buying amps you need to spend alot of money to get an amp thats up to the level of some of these old valves, and then loudspeakers can be a even bigger challenge.
But in my view they can be the ulitmate...

I have quite a nice collection of old triodes and can't imagine using anything else. I have a collection of chip amps and vintage stuff, in my view nothing comes close to a globe px25 or a globe px4 with the exception of a 1940's 300a or some of the early telefunken cosser and mazda and the likes from the late 20' s and 30's
Cheers...

[bumpy]

Thanks for the replies good people, in particular Steve - very comprehensive :)
I have the speakers and am currently looking to replace my EAR 861 which is excellent, but massively over subscribed on the power front :rolleyes:
I am carrying out my research first so I will be ready when the right amp pops up.

[Ali Tait]

It wiuld probably be better to decide which valve you want to use, then have the likes of Nick Gorham build you the amp.

[bumpy]

It wiuld probably be better to decide which valve you want to use, then have the likes of Nick Gorham build you the amp.

Who is this Nick Gorham of whom you speak?

[Ali Tait]

He makes gear under the Long Dog Audio brand. Gazjam on here has a rather nice 300b amp built by Nick.

[bumpy]

He makes gear under the Long Dog Audio brand. Gazjam on here has a rather nice 300b amp built by Nick.

I have one of his power supplies which is good. Will do a bit more research, cheers.

[paulf-2007]

As far as I know only KR make a new PX25.

[User211]

The KR PX-4 and PX-25 are gaining a very good rep with Lampizator owners.

EML 45 smooth plates and Philco 45s have been lacking in the bass region in my DAC. I am pretty sure it is a trait of the valve.

I know I am making remarks based on a DAC output stage but am pretty sure the character will show itself in higher power applications. I could be wrong, though.

[bumpy]

He makes gear under the Long Dog Audio brand. Gazjam on here has a rather nice 300b amp built by Nick.

I've been trying to contact Drew who also has an amp from Nick , but with no response. Is he still around?

Also cant find any stuff on AOS on Gazjams amp.

[Ali Tait]

Here you go-

http://theartofsound.net/forum/showthread.php?40612-Think-we-re-gonna-need-a-bigger-boat

[bumpy]

Here you go-

http://theartofsound.net/forum/showthread.php?40612-Think-we-re-gonna-need-a-bigger-boat

Thanks Ali. I have read through all that and its very encouraging :)

[topoxforddoc]

Apart from the usual suspects you can also have an one tube amplifier OTA using the EML 20B driver valve as a power valve. I have these in my 6W TRON Voyager - great sound quality and superlative build.

[bumpy]

I'm getting a pretty good feel for which triode I want, probably a 45, but my thoughts now turn to recommendations for transformers, capacitors and resistors. My budget is OK but not limitless.

On the transformer side it looks like AI amorphous cores have a good following..

[Sherwood]

Steve,

I have a number of systems and over the years have shifted between solid state and valve. Whilst I still love the immediacy and presence possible from a good valve design, I am increasingly uncomfortable with the "eco" overheads of valve amps and their low efficiency. Also, from a practical perspective, I have spent much of the last two decades working on development projects in tropical climates, where the heat output of typical valve amplifiers is both impractical and uncomfortable. However, I have recently purchased a fantastic pair of high efficiency monitors. They utilise a single Alnico full range driver and sound fantastic when driver by my Art Audio Quintet in triode mode. You mention that you have some chip amps which I know can sound very tube like. Can you recommend a good chip amp or possibly a low power SET that is more eco friendly?

Thanks

Geoff