Why did Marshall use the EL34 vs. the 6L6?

[pbman1953]

The El34 is a 25 watt tube with a current draw of 1.5 amps

The 6L6 is a 30 watt tube with a current draw of .9 amps


I'd think you could go with the same PT to run cooler with the 6L6 and get more power


Why do you think they used the EL34 over the 6L6?

[Merlin]

6L6 is an American valve, it was not very common in the UK/Europe. The Mullard/Philips valve series were the dominant market share in the UK.

[pbman1953]

Thanks!!!

[tubeswell]

its sluckey, not Sluckey

[sluckey]

its sluckey, not Sluckey

Huh???  I answer to either, but why is this posted in this thread?

[tubeswell]

its sluckey, not Sluckey

Huh???  I answer to either, but why is this posted in this thread?

Cos I'm a blow-hard LoL, ... and I don't know how this jumped threads

[sluckey]

Cos I'm a blow-hard LoL, ... and I don't know how this jumped threads

Just curious, which thread should it be in?

[glass54]

Just to add to Merlin's comment, (as I have read in the past) 6L6 vacuum tubes (and their 5881 equivalents) were difficult to come by in the UK (in the 1960's) and were relatively expensive, as US-made valves were subject to import restrictions or higher duties.
The local EL34 and EL37 were readily available and for a more rugged tube GEC KT66. These were a more cost effective tube.
I suppose that all changed by 1990's as Marshall Twin Power amps (9100/9200 Dual MonoBlocks) became available with EL34s or 6L6GC/GT.
Regards
Mirek

[dogburn]

Yep, from what I've learned, Marshall copied the Fender 5f6a Bassman circuit but substituted the EL34 that was more affordable/available in England at the time. Funny how the vagaries of politics and economics of the postwar/cold war era, led to the development of different sound of amp.

[kagliostro]

Just curious, which thread should it be in?

May be here ??

https://el34world.com/Forum/index.php?topic=33385.0

Franco

[bmccowan]

So is it tubeswell or Tubeswell?

[SoundmasterG]

The El34 is a 25 watt tube with a current draw of 1.5 amps

The 6L6 is a 30 watt tube with a current draw of .9 amps


I'd think you could go with the same PT to run cooler with the 6L6 and get more power


Why do you think they used the EL34 over the 6L6?

The choice of EL34 vs 6L6 was down to availability and price as the others have mentioned.  The EL34 can make more power than the 6L6 with a pair able to output up to 100W whereas a 6L6 pair is more like 60 watts. The plate dissipation numbers that you quoted don't correspond to output power per se.


Greg

[Jennings]

In the 50s and early 60s there were a number of utility public address type amps, for use in factories or offices and so on, that made use of the 6V6 and 6L6 in the UK.  Grampian, for example used them in several models.  And they do crop up in radios (6V6 mostly through).  But largely for the reasons above they stuck with European valves.  Brimar in the UK did make/re-brand US style tubes...their name was a compound of " British Manufactured American Radio" to reflect their main aim of making US designs available to the UK market when set up by STC.

[Merlin]

In the 1950s British appliance manufacturers were slapped with export quotas by the government. Grampian were required by law to sell only a fraction of their products to British consumers, the rest had to go abroad.* A lot of mass-produced products were therefore aimed at the American market, and I suspect that is where most Brimar valves went. Marshall weren't in the same league as radio/TV producers of course.
*Yes, this was as economically dumb as it sounds.

[pdf64]

I suspect Brimar never made a 6L6GC (the 5 layer anode technology seems like it may be unfeasibly expensive to implement at low production volumes https://n4trb.com/AmateurRadio/GE_HamNews/issues/GE%20Ham%20News%20Vol%2015%20No%201.pdf).

[pdf64]

The El34 is a 25 watt tube

That's under the design centre rating system.

The 6L6 is a 30 watt tube

That's specifically the 6L6GC, and it's under the design maximum rating system.
Hence the numbers are not directly comparable.
A 6L6GC would probably have an anode dissipation limiting value of about 26W under the design centre rating system.

Also the EL34 anode voltage limiting value is much higher than that of the 6L6GC.

The EL34 ... current draw of 1.5 amps

The 6L6 ... current draw of .9 amps

I'd think you could go with the same PT to run cooler with the 6L6

3.8W difference in heater power per valve seems trivial?
I can't perceive an advantage in reducing the loading by that degree for a mains transformer designed to accommodate EL34?

I'd think you could go with ... the 6L6 and get more power

You may not be considering the differing anode curves / characteristics, and hence 'best fit' loadlines, of those valve types?

Generally, swapping 6L6 family valves into EL34 circuits will result in a slightly lower maximum power output.

https://frank.pocnet.net/sheets/010/e/EL34.pdf
https://frank.pocnet.net/sheets/093/6/6L6GC.pdf
https://www.one-electron.com/Archives/RCA/RCA-AppNotes/RCA%201958%20AN-174%20Design-Maximum%20System%20for%20Rating%20Electron%20Tubes.pdf