transalted from Mr Ohashi's Blog
SV-310 EX/V-Cap 120V specifications
June 25, 2025Shipping inspection of the export specification SV-310 began today.
A commemorative photo with Western Electric 310B and JAN 274B installed. The export version will be shipped without vacuum tubes, so we will conduct a power-on test under the same conditions using PSVANE WE310A and PSVANE WE274B in our stock as standard tubes.
The coupling cap is Oil Damped Advanced Metalized (ODAM) V-Cap is provided by the distributor . Other specifications are the same
as those of the domestic model.
We check the quality of each machine like this, but there are machines piled up behind us waiting for inspection, so it feels like there is still a long way to go.
This triple check system involves a self-inspection by the assembly craftsmen, a secondary inspection by the subcontractor, and finally a final inspection by me, which takes time and effort, but I will make sure that the products are "made in Japan, as you would expect." We plan to complete the inspection of all units by the end of this week.
I don't think there are any other examples of transformer output preamps overseas, but according to our distributor, they've already received a lot of preorders. We're looking forward to seeing the reactions of local customers.
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SV310EX should be available in August
65% of the August shipment were sold.
65% of the August shipment were sold.
Here is the Eye Candy 😛 version of the tube: wire mesh plates
Super rare Western Electric 337A in place of the 310A.
Much more open sound than the drilled hole plate version.
Super rare Western Electric 337A in place of the 310A.
Much more open sound than the drilled hole plate version.
337A AND 310A are different in characteristics..
SV310 is designed based on 310A.. not 337A..
The Plate current and Transconductance are totaly different..
337A
https://static1.squarespace.com/sta...4557b772b8b174429c10e6/1598379959797/337A.pdf
310A
https://static1.squarespace.com/sta...4557b772b8b174429c10e6/1598379959797/310A.pdf
If you have bigger budget you can buy Western Electric 310A Small Punch. 2.5 times more .
SV310 is designed based on 310A.. not 337A..
The Plate current and Transconductance are totaly different..
337A
https://static1.squarespace.com/sta...4557b772b8b174429c10e6/1598379959797/337A.pdf
310A
https://static1.squarespace.com/sta...4557b772b8b174429c10e6/1598379959797/310A.pdf
If you have bigger budget you can buy Western Electric 310A Small Punch. 2.5 times more .
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Hi Victor, I totally agreed with your comments.
The datasheets for both tubes are indeed different, but that doesn’t mean they won’t work in this setup. As a tube roller, I'm always experimenting to chase different sounds. When I saw a Japanese guy using the 337A this way, I got curious—dug into the datasheet and tried to understand why it might work.
What piqued my curiosity was Jeff's positive feedback on the WE310A mesh plates, especially in his review of the mesh plates used in the WE91B amplifier with the DA30 and WE310A mesh tubes.
WE91b using DA30 and WE310A mesh
Turns out, the two tubes are actually quite close. The 337A runs a little hotter with more current, which gives it a warmer, richer, almost seductive tone. And with its true wire mesh plate, it easily outshines the drilled-plate versions.
I’ve got both small-hole and large-hole 310As in my collection—but not the elusive wire mesh plates. Those are rare and pricey, going for around $2,500 a pair.
This is a cheap attempt to get a mesh plate version to experiment. They cost more than the regular 310A ( if you can find a mesh plate 337a , $500 each )
I just wanted to share my experiment with the SV-310 preamp as it turns out to be outstanding sound.
The datasheets for both tubes are indeed different, but that doesn’t mean they won’t work in this setup. As a tube roller, I'm always experimenting to chase different sounds. When I saw a Japanese guy using the 337A this way, I got curious—dug into the datasheet and tried to understand why it might work.
What piqued my curiosity was Jeff's positive feedback on the WE310A mesh plates, especially in his review of the mesh plates used in the WE91B amplifier with the DA30 and WE310A mesh tubes.
WE91b using DA30 and WE310A mesh
Turns out, the two tubes are actually quite close. The 337A runs a little hotter with more current, which gives it a warmer, richer, almost seductive tone. And with its true wire mesh plate, it easily outshines the drilled-plate versions.
I’ve got both small-hole and large-hole 310As in my collection—but not the elusive wire mesh plates. Those are rare and pricey, going for around $2,500 a pair.
This is a cheap attempt to get a mesh plate version to experiment. They cost more than the regular 310A ( if you can find a mesh plate 337a , $500 each )
I just wanted to share my experiment with the SV-310 preamp as it turns out to be outstanding sound.
Thank you, Victor—your thorough layout and insightful comments really help buyers make the most of this preamp. The upgraded capacitor, in contrast to the stock version, makes a noticeable impact by eliminating background noise and delivering deeper, more defined bass.