Description

Quantity FIVE(5) AMPEREX 'Selected' Heerlen, Holland Vacuum Tubes, Dated 3x1962 + 2x1964 Amperex inked 'Bugle Boy' HEERLEN, HOLLAND production ECC88 6DJ8 PRE-Amplifier Tubes. Glass etched : 'GAx' + 'Δ2K2', 'Δ2J2', 'Δ2xx', 'Δ4C2', 'Δ4xx' All 5 tubes have clear or partially visible Bugle Boy logos (see pics), each tube is white ink dated on glass, Dates range from 1962 & 1964 Smaller Ringed Halo Top-Side Getter Vacuum Tubes (Please preview in detail all pics) All 5 Tested with a Recently Dan Nelson Calibrated TV7D/U AT OR ABOVE Average Vintage Amperex Factory Data Sheet Strong and Nicely Balanced Transconductance(Gm) & mA Plate Current emissions - All 5 were 'Selected' by Amperex for Tektronix Professional Lab Test Equipment ( High-End Professional Oscilloscope) - ALL made in Amperex Heerlen, Holland Foundry - Smaller Ringed Halo Getter - White inked - 4 seamed Top glass - 3 Wafer/Spacers, 2 Mica Spiked Wafers + 1 Solid Metal Spacer (resembles Clover-Leaf) with 2 metal supports and 1 thick metal support upward for the Smaller sized Ringed Halo Getter - Smooth Boxed Gray Plates - 360 degrees Top Silver Flashing -Tubes will ship in 9-pin Amperex boxes (3 new Amperex + 2 vintage re-labeled Amperex boxes). Each box and tube marked in black removable Sharpee "T2, T3,T5,T8,T11" corresponding to the test results below. We marked lightly with removable black Sharpee the #'s 2, 3,5,8,11 on top of the silver flashing glass for tube identification and non-inked side of each tube for easy identification so you maybe able to match up pairs easier. Our Test Bench : TV7D/U Restored, Enhanced & Upgraded( Digital Meter) by Dan Nelson Calibrated( 07/24/2023). Calibration re-verified on 01/03/2024 & 6/07/2024. Condition/Providence : ALL 5 are PLUG-IN and PLAY Condition. All 5 Tubes tested Balanced & Strong for Gm & mA emissions as Used Equipment Pulls from Tektronixs high end Oscilloscopes (premium selected tubes by Amperex for Tektronixs Test Equipment), Minimum good TV7 meter reads 62=7,750 uMhos Transconductance( Gm ) per side which is 62% of factory average new. ECC88 6DJ8 'Bogey' = Vintage Amperex Factory new TV7's will on average read 100/100 per plate (+/- 10%) which is 12,500 uMhos Transconductance(Gm) at 15mA Anode Plate Current Emissions per side. Vintage Factory plate matching would pass QA inspection if plate were <= 10% match. All 4 tested balanced at Premium factory QA release at <= 5%. Amperex Factory retail sales entertainment tubes Plate matching would pass QA if plates were <= 10% matched. However after testing many premium ECC88's Tektronix & HP pulls made by Amperex, Mullard & Telefunken the plate matching is generally <= 5% on these 'selected' tubes. All Tested : No Shorts, No Gas, No Leakage, No Apparent Micro-Phonics detected TEST RESULTS : Providence given in pics listed. Tube #2 (T2) : 'GAx' 'Δ2xx' ,1962 white inked '3 02' ( 93.557% Gm exact match, balanced plates 6.45%) Plate#1 : 100.2 = 12,525.0 uMhos(Gm) at 20.7mA Plate Current emissions Plate#2 : 107.1 = 13,387.5 uMhos(Gm) at 23.7mA Plate Current emissions Tube #3 (T3) : 'GAx' 'Δ2xx', 1962 white inked '2 37' ( 99.696% Gm exact match, balanced plates <1%) Plate#1 : 98.5 = 12,312,5 uMhos(Gm) at 18.9mA Plate Current emissions Plate#2 : 98.8 = 13,350.0 uMhos(Gm) at 20.4mA Plate Current emissions Tube #5 (T5): 'GAx' 'Δ2K2', 1962 white inked '3 04' ( 96.914% Gm exact match, balanced plates 3.1% ) Plate#1 : 100.5 = 12,562.5 uMhos(Gm) at 23,3mA Plate Current emissions Plate#2 : 103.7 = 12,962.5 uMhos(Gm) at 22.2mA Plate Current emissions Tube #8 (T8): 'GAx' 'Δ4C2',1964 white inked '4 10' ( 97.762 % Gm exact match, balanced plates 2.4% ) Plate#1 : 100.5 = 12,562.5 uMhos(Gm) at 24.4mA Plate Current emissions Plate#2 : 102.8 = 12,850.0 uMhos(Gm) at 23.1mA Plate Current emissions Tube #11 (T11): 'GAx' 'Δ4xx', 1964 white inked '64 45' ( 97.685 % Gm exact match, balanced plates 2.3%) Plate#1 : 101.3 = 12,662.5 uMhos(Gm) at 22.0mA Plate Current emissions Plate#2 : 103.7 = 12,962.5 uMhos(Gm) at 23.0mA Plate Current emissions Published TV7 Settings (1962): ECC88/6DJ8 Vf=6.3V EV7- 6080 Bias=20 Range =D Gm Button =3 Min. Good =62 Triode #1. ECC88/6DJ8 Vf=6.3V EV2-1030 Bias=20 Range =D Gm Button =3 Min. Good =62 Triode #2. Spec Reference : Philips / Amperex ECC88 6DJ8 'Low Noise Double Triode' Data Sheet Dated 1957-58): (thank you! frank dot pocnet dot net) Filament/Heater Vf: 6.3V If: 365 mA Ampere Factory specs when tested at 90VDC Plate supply Volts( Va=90V), Control Grid( Vg1= -1,3V) S= 12,5 mA/V = Factory new Transconductance(Gm)=12,500 uMhos = a TV7 meter reading of 100. Ia= 15mA = Factory new Anode Plate Current Emissions Mu (Amplification factor=33) WE PACK VERY WELL AND SHIP FAST TO OVER 100 COUNTRIES WORLDWIDE MANY Years of Experience shipping fragile electronics, speakers and Vacuum Tubes. US Shipping to All 50 States & US Territories + APO/DPO/FPO/xPO & PO Boxes International via eBay International Shipping Center - low cost space available Air-Freight with Tracking. Ebay's international ship partners are USPS International, DHL & Asendia. Allow 10days to up to 6weeks for delivery depending upon country of destination. IF YOUR COUNTRY IS LISTED IN THE DROP DOWN BOX IN THE 'SHIPPING, HANDELING' TAB Listing THEN WE SHIP TO YOU.