UX4 - Wired - Ceramic - Gold

The classical American UX4 socket. Nicely rebuild, excellent quality with good "feel" when inserting and removing the tubes. Ceramic, gold plated Version.

Order Number:
399-075-95

Octal PCB type

PTFE (Like Teflon) Gold - Beryllium Contacts

These have 10 contacts per pin.

Printed Circuit Board Version

Pin Radius on PCB
25,4mm  / One Inch

Tubes like:
KT88, EL34

Order Number:
399-077-68

Chinese Loctal

We have stopped selling those. We recommend NOT to use them. These are a bad hack. They crack the glass along the tube pins, with some percentage of your tubes. Leading to slow vacuum loss, which the user thinks to blame on the tubes. Also Yamamoto Loctal is no alternative. These don't damage the tubes, but they can develop a crack noise over time, . We recommend ONLY NOS LOCTAL sockets. Reasons are explained in the link at the end of this text. It is not funny when you find a 250 Euro NOS Telefunken C3g dead after three weeks, due to vacuum loss. Unfortunately, the as long as it sells, the Chinese keep on making them.

Any Loctal tubes you buy from us, we do not guarantee them, if used with Chinese Loctal sockets.

Nothing against Chinese sockets in general, most of them are well done. Just not so much the Noval (they bend the pins) and the Loctal (They crack the glass) .

NOS is the only reliable LOCTAL socket. There is no other.

More details here

mounting options

Note, with sockets that have detachable clamp rings, you can attach the clamp in two positions, allowing positioning of the tube at 0, 90, 180, or 270 degrees. So always have the tube orientation as you want it.

Chassis hole 21.2mm
Screw distance 30mm

Silver Version
Order Number: 320-019-67

Silver Version only

WIth this socket you can much increase your possible choice of tubes. Use of 1930's European tubes and USA tubes are possible in the same circuit now!.

Even though European tubes are 4V and USA tubes at 5V, it can be done. So this socket combines:

• European B4 base (normally 4V tubes)
• USA UX4 base (normally 5V tubes)

Part 1. Use 4V or 5V Rectifiers by just plug them in.

European rectifiers are available in much nicer variations, globe glass and mesh types can be found still. When you do this with a 5U4G circuit, the 5Z3 is the UX4 version of 5U4G. So this is the one tube. The European tube is RGN2504, PV200/600 or AZ50. (See our NOS pages) for rectifiers. Or switch from Type 83 mercury to AX50 Mercury.

The difference in filament voltage is solved with small series resistors. These do not even get very warm, and can be mountectly on the socket, and that's all you need to do.

Click here to see how it's connected for rectifiers.

Part 2. Use 4V or 5V Triodes by just plug them in.

This socket combines an UX4 socket with UV4 sockets. Why is that?
When you build a 205D amplifier, you can use the Fullmusic 205D, which has a UX4 socket.
Then later, just suppose you get the idea to try NOS 205D, these have an older type socket (UV4).
With this socket, all you need to do is rotate the tube 90 degrees, and it will take both types.
There are many other interesting tube combinations possible with this socket.

READ ALSO with the UX4-B4 socket for ideas about possible other applications.

Gold version only

Loctal
Tubes like: C3g, C3m, ECH21

I am sorry, as much as we like the Yamamoto sockets: We do NOT recommend to the Yamamoto LOCTAL socket.

Instead, we were able to buy a large stock of NOS Teflon sockets made by EDISWAN, England. These have silver plated contacts, and the same screw hole dimensions as the Yamamoto.

Order number for the EDISWAN TEFLON socket:
398-803-99

More information here

Only Gold Version

Application #2 (28mm to 38mm screw distance)

This allows to mount the Yamamoto 18mm hole socket in standard 30mm holes, as for octal sockets. Very useful when you want to use a noval based tube, where these is an octal hole in the amplifier deck.

The small holes of the base plate are used to mount the Yamamoto socket invisible. The large holes are used for the octal footprint.

A general purpose high quality screw set is provided with the base plate.

Teflon Audio Input / RCA Jack

Fully CNC machined part. Made from Teflon, Bronze, Silver, Gold and nothing else. These have nickel free contacts.
Each comes with four color rings, so you can color mark each connector the way you prefer.
Standard 9mm chassis hole.

This part can be used for both symmetrical (XLR) or unsymmetrical (normal RCA ) inputs. For normal mounting, the inner Teflon isolator ring is not used. So the connector is grounded to the chassis like this. If you need symmetrical inputs, you apply both isolator rings.

They feature coaxial ground connections. Engineers will love this. If you do not want to take advantage of this, there is no need of course, and you can connect only the signal wire to the center pin (same as with low cost connectors). For improved shielding however, you can consider to connect a shielded coaxial cable to it, and then you can make a nice coaxial connection without having a shield leakage at the input connector. So the outside of the coaxial cable goes around the connector. In cases like this, the outside of the cable is connected to the connector only. At the other end where it goes into the amplifier, the shield is not connected. This provides ultimate shielding, and prevents ground loops.

Special note about the gold plating of those. These connectors are little diamonds, build with ultimate contact quality in mind. When you first see them, they look not mirror-shiny, and there are sometimes questions about this. For Audio Signals it is best to have nickel free contacts, to prevent whisker noise when the contacts get old. This means the whole construction and the plating must be nickel free. Perhaps as you know, a mirror shiny gold plating results only when a nickel layer is applied underneath, and also a non-pure gold layer, is used with low gold content. Since all Yamamoto parts are nickel-free, and use pure gold only, this cannot be done on a mirror-shiny way. For best electrical results, a pure silver plating must be underneath. (Reason for this is to be found in the inter-metallic potential when two metals of different kind touch each other). This layer of pure silver However, has an opaque surface. Over the silver, several gold layers are applied, which will adopt the opaque surface as well. So please be not mislead when you first see them, and notice the plating is not done mirror -shiny! This is done in purpose, for best contact results.