I have 4 super rare very strong tv7 tested Mullard box plate M8137 / CV4004 / 12AX7 tubes

MULLARD VALVE M8137 CV4004 white print made in Great Britain date / factory codes-- looks like 641R1G1

MULLARD Valve M8137 CV4004 boxed new old stock made in Great Britain KB/D date and factory codes are not very clear looks like -- 64.1 R3D2

RARE STRONG MATCHED PAIR OF MULLARD M8137 CV4004 ECC83 PRINT WORN BUT CODES VISIBLE DATED TO 1965 AND 1967 IN GOOD CONDITION AND PERFECT WORKING ORDER - TESTED STRONG ??AVO VCM163 TESTED READINGS TUBE 1 - Ia 1.4/1.3 gm 1.6/1.7 TUBE 2 - Ia 1.9/1.7 gm 1.8/1.7 100% = Ia 1.2 gm 1.6 ? PLEASE SEE MY OTHER AUCTIONS ?

Mullard M8137 CV4004 KB/D. Condition of this item looks good. I am unable to test, so it’s sold as seen. For exact international postage rates, please contact me.

WELCOME TO YET ANOTHER GREAT DR-TRON AUCTION. THIS SALE IS FOR A VINTAGE VALVE TUBE..... Mullard M8137, CV4004, ECC83 / 12AX7CV4004 KB/D. WHITE PRINT.HALO GETTER. Box Anode plates. MADE IN Great Britain. Code = 641-R8G4.TESTS 100%..A1 = 1.90mA. A2 = 1.75mA..... 100% = 1.2mA.FROM WORKING EQUIPMENT. Please note...... ALL MY TUBES ARE TESTED ON MY CALIBRATED ...... AVO VCM-163 TUBE TESTER .... BEAR IN MIND ALL TUBE TESTERS GIVE SLIGHTLY DIFFERENT READINGS..... MY READINGS ARE ACCURATE AND HONEST. I WILL SHIP THIS ITEM WORLDWIDE. PLEASE LOOK AT MY OTHER VINTAGE PARTS AUCTIONS. THANK YOU FOR TAKING TIME TO VIEW MY ITEM, AND GOOD LUCK !!!

2x Mullard ECC83 Valves Date Code: I61 B2H2, I61 B2H2 Tested by AVO VCM Tester Valve 1 Ia1 = 0.85(mA), gm1 = 1.3(mA/V) Ia2 = 1.05(mA), gm2 = 1.4(mA/V) Valve 2 Ia1 = 1.02(mA), gm1 = 1.45(mA/V) Ia2 = 0.8(mA), gm2 = 1.3(mA/V) NOS specification: Ia = 1.2(mA), gm = 1.6(mA/V) *** This valve has also been tested in amplifier without any noise. *** Postage Costs I am happy to post this item to worldwide and combine postage cost on multiple purchases. 20230522L017

2x Mullard 12AX7S/CV4004 Valves This pair of 12AX7S/CV4004 are with very unique box-anode construction. They are believed manufactured by Mullard Mitcham factory Tested by AVO VCM Tester Valve 1 Ia1 = 0.7(mA), gm1 = 1.25(mA/V) Ia2 = 0.8(mA), gm2 = 1.3(mA/V) Valve 2 Ia1 = 0.78(mA), gm1 = 1.3(mA/V) Ia2 = 0.8(mA), gm2 = 1.35(mA/V) NOS specification: Ia = 1.2(mA), gm = 1.6(mA/V) *** This valve has also been tested in amplifier without any noise. *** Postage Costs I am happy to post this item to worldwide and combine postage cost on multiple purchases. 20230522L004

2x Mullard ECC83 Valves Very rare pair of Mullard ECC83 manufactured in 1955 with long-plate and []-getter Date Code: mC1 B5F, mC1 B5F Tested by AVO VCM Tester Valve 1 Ia1 = 1.32(mA), gm1 = 1.55(mA/V) Ia2 = 1.45(mA), gm2 = 1.4(mA/V) Valve 2 Ia1 = 1.23(mA), gm1 = 1.5(mA/V) Ia2 = 1.48(mA), gm2 = 1.45(mA/V) NOS specification: Ia = 1.2(mA), gm = 1.6(mA/V) *** This valve has also been tested in amplifier without any noise. *** Postage Costs I am happy to post this item to worldwide and combine postage cost on multiple purchases. 20230522L001

2x Mullard ECC83 Valves Date Code: I61 B3B4, I61 **** Yellow pirnt, copper-grid-support, and halo-getter Tested by AVO VCM Tester Valve 1 Ia1 = 0.85(mA), gm1 = 1.5(mA/V) Ia2 = 2(mA), gm2 = 1.8(mA/V) Valve 2 Ia1 = 1.55(mA), gm1 = 1.7(mA/V) Ia2 = 1.3(mA), gm2 = 1.5(mA/V) NOS specification: Ia = 1.2(mA), gm = 1.6(mA/V) *** This valve has also been tested in amplifier without any noise. *** Postage Costs I am happy to post this item to worldwide and combine postage cost on multiple purchases. 20221122L016

For your consideration are two Mullard M8137 cv4004 with matching date codes. These are the military versions of Mullards 12AX7/ECC83 These tubes were tested in a Hickok 539C where the minimum reading is 875gm and the reading for a new tube is 1375gm. The tubes tested at 1600gm/1500GM & 1600gm/1600gm

1x Mullard CV492 Valve Very rare Mullard CV492/ECC83 with long plate and []-getter, new in original box Date Code: mC1 B6H (1956) Tested by AVO VCM Tester Ia1 = 1.58(mA), gm1 = 1.9(mA/V) Ia2 = 1.43(mA), gm2 = 1.7(mA/V) NOS specification: Ia = 1.2(mA), gm = 1.6(mA/V) *** This valve has also been tested in amplifier without any noise. *** Postage Costs I am happy to post this item to worldwide and combine postage cost on multiple purchases. 20230522L020

1x Mullard CV4035 Valve Date Code: AG0 R7G(1957) NOS, soldered to a B9A pinout and can directly replace any CV4004/M8137/CV491/ECC83/12AX7 valve Tested by AVO VCM Tester Ia1 = 1.25(mA), gm1 = 1.7(mA/V) Ia2 = 1.45(mA), gm2 = 1.8(mA/V) NOS specification: Ia = (mA), gm = (mA/V) *** This valve has also been tested in amplifier without any noise. *** Postage Costs I am happy to post this item to worldwide and combine postage cost on multiple purchases. 20221122L014

1x Mullard CV492 Valve Very rare Mullard CV492/ECC83 with long plate and []-getter, new in original box Date Code: mC1 B6H (1956) Tested by AVO VCM Tester Ia1 = 1.58(mA), gm1 = 1.9(mA/V) Ia2 = 1.43(mA), gm2 = 1.7(mA/V) NOS specification: Ia = 1.2(mA), gm = 1.6(mA/V) *** This valve has also been tested in amplifier without any noise. *** Postage Costs I am happy to post this item to worldwide and combine postage cost on multiple purchases. 20230522L020

2x Mullard ECC83 Valves Very rare pair of Mullard ECC83 manufactured in 1955 with long-plate and []-getter Date Code: mC1 B5F, mC1 B5F Tested by AVO VCM Tester Valve 1 Ia1 = 1.32(mA), gm1 = 1.55(mA/V) Ia2 = 1.45(mA), gm2 = 1.4(mA/V) Valve 2 Ia1 = 1.23(mA), gm1 = 1.5(mA/V) Ia2 = 1.48(mA), gm2 = 1.45(mA/V) NOS specification: Ia = 1.2(mA), gm = 1.6(mA/V) *** This valve has also been tested in amplifier without any noise. *** Postage Costs I am happy to post this item to worldwide and combine postage cost on multiple purchases. 20230522L001

2x Mullard ECC83 Valves Date Code: I61 B3B4, I61 **** Yellow pirnt, copper-grid-support, and halo-getter Tested by AVO VCM Tester Valve 1 Ia1 = 0.85(mA), gm1 = 1.5(mA/V) Ia2 = 2(mA), gm2 = 1.8(mA/V) Valve 2 Ia1 = 1.55(mA), gm1 = 1.7(mA/V) Ia2 = 1.3(mA), gm2 = 1.5(mA/V) NOS specification: Ia = 1.2(mA), gm = 1.6(mA/V) *** This valve has also been tested in amplifier without any noise. *** Postage Costs I am happy to post this item to worldwide and combine postage cost on multiple purchases. 20221122L016

1x Mullard CV4035 Valve Date Code: AG0 R7G(1957) NOS, soldered to a B9A pinout and can directly replace any CV4004/M8137/CV491/ECC83/12AX7 valve Tested by AVO VCM Tester Ia1 = 1.25(mA), gm1 = 1.7(mA/V) Ia2 = 1.45(mA), gm2 = 1.8(mA/V) NOS specification: Ia = (mA), gm = (mA/V) *** This valve has also been tested in amplifier without any noise. *** Postage Costs I am happy to post this item to worldwide and combine postage cost on multiple purchases. 20221122L014

2 X Mullard M8137 CV4004 KB/D. Condition looks good, supplied with original boxes and wrapping. These items are sold as seen and untested.

1x Mullard ECC83 Valve Date Code: ?3 mCA (1953) Very rare ECC83 from Copenhagen factory with long welded plate and D-getter Tested by AVO VCM Tester Ia1 = 1.2(mA), gm1 = 1.45(mA/V) Ia2 = 0.9(mA), gm2 = 1.3(mA/V) NOS specification: Ia = 1.2(mA), gm = 1.6(mA/V) *** This valve has also been tested in amplifier without any noise. *** Postage Costs I am happy to post this item to worldwide and combine postage cost on multiple purchases. 20230522L006

Mullard CV4004 M8137 Special Quality Box Plate Valve This type is a special quality robust version of the ECC83 or 12AX7 double triode.Tested on an AVO VCM MkII results are: A1: Ia 1.55mA. Gm 2.2mA/VA2: Ia 1.35mA. Gm 2.1mA/V (Avo spec. for ECC83 is 1.2mA, 1.6mA/V) On 14-May-23 at 18:34:23 BST, seller added the following information: Supplied in white box

MULLARD CV4004 M8137 12AX7 ECC83 VALVE TUBE GOOD QUALITY BRITISH

2 X Mullard M8137 Vacuum tubes. They appear to be new and unused and in original wrapping. These items are sold as seen and untested.

A pair of ECC83 M8137 CV4004 12AX7 special quality valves.Both made at the Mitcham factory, etch codes are R9F5 (1959 June week 5) & R4D2 (1964 April, week 2)The M8137 is characterised by a large halo getter used to increase the quality of the vacuum.Tested on an AVO CV160Results are:Valve 1 Anode 1, 1.2mA 1.8gm - Anode 2, 1.2mA 1.8gmValve 2 Anode 1, 1.2mA 2.0gm - Anode 2, 1.2mA 1.9gmBoth valves exceed the standard for ECC83Very stable and quick warming.

Mullard CV4004 M8137 Used Special Quality Box Plate Valve This type is a special quality robust version of the ECC83 or 12AX7 double triode.Tested on an AVO VCM the results are perfectly matched: A1: Ia 1.3mA. Gm 2.05mA/VA2: Ia 1.3mA. Gm 2.05mA/V (Avo spec. for ECC83 is 1.2mA, 1.6mA/V) Supplied in brown box