Wow, someone whose moniker is actually my favorite tube, the Western Electric 421a! I use Oliver Sayes’ 421a to drive my Klipsch La Scalas. Heavenly sound from one power tube for both channels. Not sure why this tube is not more well known. I like it more than the WE 300b. But 3W is all you get, which is way more than I need.
SET amp owners thread
- Thread starter bonzo75
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Yes. I started my WE tube journey with this tube. Here is my 421A PP 20 years back. I was not into SET then since I was only using bookshelf speakers ATC SCM10. I started getting into high efficiency speakers with the vintage Jensen coaxial 12
I don’t know about how much you “need”. I have 18 SET watts into a 16 ohm load speaker that is 105 dB. I might use 10% of the power when I have it cranking, but the beauty of that is that the distortion is super low. it’s nice to be able to use a mere fraction of an amplifier’s power rating knowing you have the headroom but not needing it to keep distortion low.
I don’t listen anywhere that loud: one reason my hearing is intact after 35+ of owning high end audio equipment. I keep the average volume in the mid 70dBs with peaks getting into perhaps the 90dB range. That’s still only a tenth of a watt from a SET. Even my 45 based SET monoblocks that generate about a watt each seem plenty loud to me.
I’d love for someone to create a company called First Milliwatt and produce high quality milliwatt amplifiers! I think about 100 milliwatts is all I need for my La Scalas!
I’d love for someone to create a company called First Milliwatt and produce high quality milliwatt amplifiers! I think about 100 milliwatts is all I need for my La Scalas!
Nelson Pass's famous word on his website, Nelson writes, “Dick Olsher famously remarked that “The first watt is the most important watt.” "
He then created the site in 1998
Right, but we want a new slogan: the first (10?) milliwatt is the most important! I have the First Watt J2, which produces about 25 watts per channel. Way too much. Mr. Pass should focus on 1 watt designs! The problem is that 25 watts is way too little for average 86 dB designs and way too much for 105 dB designs.
I listen at the same volume you do. 70 DB peaks maybe 90. I might use a watt On challenging music at volume, which is less than 10% of available power. I’ve looked at the distortion curves and they’re very low when you use less than a watt for my amps, perhaps a 10th of a watt with my speakers. We agree on this.
A lot of the standard ideas in amplifier design come from thinking about average sensitivity speakers around 86 dB. The standard rule is to allow for 20 dB peaks, so 100 watts are needed to reach around 100 dB with an average sensitivity speaker. But this logic doesn’t apply to highly efficient 105 dB designs.
There is another factor that needs to be taken into consideration. The listening environment matters. The larger the room, the more headroom you would need. It varies from one listening room to another. That said, the same Tannory GRF memory speakers I own in my room vs my other friend who has the same speaker changes dramatically as the room size matters. I use SET but he prefers McIntosh MC60. His listening room is 4 times larger than mine. In my space, even a one-watt EL84 single-ended is enough to drive the Tannoy. In his space, he will need 30 watts amp to fill the room. I think there is no definite answer based on the speaker's efficiency.
The other tweak to try is to replace the polypropylene capacitors that bypass the electrolytic capacitors with a Jensen copper foil in oil of the same value. I did that in my Cary amps and liked it a lot. Use the same value and connections as the polypropylene capacitor being replaced.
Have you ever had a 2a3 amp with interstage transformer coupling? I find amps that use trafo coupling tend to sound more dynamic and seemingly more powerful.
Had 300b DRD. Not 2A3。 no direct comparison. Good low level but bass was lacking with 6j5 driver
I have heard some quite good direct coupling amps (NAT for example) but never like for like. The closest comparison would be to the Aries Cerat Genus and Diana, which are transformer coupled, using an 813 instead of a 211. No SET I have ever heard has the drive and grunt of AC amps…none. The 42 watt Amplifon SET42SE (cap coupled) was also very good but didn’t have that atomic core of seemingly endless power of the AC amps. Also, the Ayon Crossfire iii didn’t get there either, despite othe strengths.
I never thought at the time the transformer coupling was somewhat responsible for this sense of drive and power…I thought it was more power supply.
Then I got this “little” 2A3 amp from Silvercore with transformer coupling and damned if it doesn’t sound a whole lot like a mini AC amp.
Silvercore does cap coupling too. All his amps have drive. Mayer does transformer coupling, I find his amps more like what we421a described. The GM70 I like is cap coupled and has great drive, and some of his other cap coupled amps don’t. I won’t read into this, there are many other things going on in an amp rather than a house design. I know at least 3 manufacturers whose SETs I like whose other SETs I don’t
Hey Bonzo - which GM70 amp would that be. A GM70 amp is on my bucket list & I will never get to hear any before buying so will be reliant on others I trust for recommendations - thanks...
My take on “drive” in single ended :
If your single ended can match a push pull amp in terms of drive and dynamic, congratulations! you have a very good single ended amp.
If your single ended can match a push pull amp in terms of drive and dynamic, congratulations! you have a very good single ended amp.
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