Description
Nice pair M8136 (ECC802S) twin triodes, Excellent condition, made by Mitcham in Blackburn, UK
This is a pair M8136 tubes produced by Mullard in the sixties and seventies in Mitcham, United Kingdom. The tubes have so called box plates, which is considered superior to the conventional construction; see pictures. The getter is mounted on a copper post and the grids are on copper posts also.
The M8136 is the military long life ECC82 that was specially designed for the British forces.The tubes both look unused and measure new ; see test data! Very healthy tubes in deed with NOS specs! Tubes with matching systems; see test results.
Sonics
The Mullard M8136 is highly regarded. I refer to the many threads on the web for more information. Very musical preamp valve, balanced and sweet sounding, softened without losing detail with liquid full midrange, recommended!
From the internet: The valve produces the most detailed mid-range response of any ECC82 type ever made. This trademark sound has led many audio reviews to state that this is the best of its type ever made. The valve has a super warm sound with plenty of mid-range detail. Indeed in our test reports the female vocal and string sections were simply stunning. Verdict of a buyer: The sound is excellent – tight, spacey and clean, well balanced with a smooth top end.
Test results*
| Valve 1
V222 |
Ia (plate current):
Transconductance (Gm): Gas test, Shorts test: |
10,3/ 10,2 mA
2,4/ 2,3 mA/V OK |
= NOS
= NOS |
| Valve 2
V223 |
Ia (plate current):
Transconductance (Gm): Gas test, Shorts test: |
10,4/ 10,2 mA
2,3/ 2,3 mA/V OK |
= NOS
= NOS
|
Where NOS is : Ia = 8,7 to 12,5mA, Gm= 1,9 to 2,7 mA/V. Ia = 10,6 ± 1,9 mA. (Telefunken data sheet)
Short description
| Tube type | M8136, (ECC802S) |
| Quantity of Tubes | One pair |
| Brand | Mullard |
| Manufactured in | Mitcham, UK |
| Dates | Date codes:631 R8L2 & 631 R 8K3) |
| Construction | Box plates |
| Getter Construction | Halo getter on copper post |
| Print Condition | Very nice; see pictures |
| Box included | White box |
| Equivalent tubes: | 12AU7, ECC802S, CV4003, 12AU7A |
| General test results | NOS |
