Matched Pair Mullard EL34 Vacuum Tube/Valve NOS Metal Base 1957, Philips Heerlen

Matched pair of early Mullard EL34 output valves with metal bases, manufactured in the Philips Heerlen factory in The Netherlands during 1957.

Both valves carry the identical factory/date code SV1-57C and are branded Mullard, although as was common during this period they are marked "Made in Holland".

One valve retains most of its original Mullard transfer while the second shows only a faint ghost of the original printing, almost certainly due to handling and storage over the intervening decades.

Both valves have bright, clean pins and matching factory codes, characteristics that are entirely consistent with long-term storage rather than prolonged service use. The metal bases show some light age-related tarnishing. Original cartons are not included.

These early Philips Heerlen manufactured metal-base EL34s require little introduction and are widely regarded as one of the most desirable variants of the EL34 ever produced.

Test Results (AVO Mk III)

Both valves test essentially on specification for anode current, with one slightly above and one slightly below the AVO data manual figure.

Transconductance is identical at 12mA/V, exceeding the book figure of 11mA/V and providing excellent balance between the pair.

The identical factory codes and identical gm figures make these a genuine and practical matched pair suitable for use in high fidelity and guitar amplifier equipment.

Summary

• Matched pair of Mullard EL34 output valves
• Early metal-base construction
• Manufactured by Philips Heerlen in The Netherlands
• Date/factory code SV1-57C on both valves
• Mullard branded and marked "Made in Holland"
• Identical transconductance figures of 12mA/V
• Tested on an AVO Mk III valve tester
• Bright unworn pins consistent with long-term storage
• One strong Mullard logo and one ghost logo
• Original boxes not included

The valves will be packed very carefully for shipping.