EL34 vs 6L6 for HiFi

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BTW, can 6L6G be directly plug into an EL34 amp?

Have this Eico HF89 that uses EL34, pumping out 50 watts per channel.
UL design, 475v on plate @ 50mA.

if using cathode resistor biasing instead of fixed bias, you can....
i purchased a quad of JJ 6V6 and when it arrived it says 6L6GC on the bottle,
so i went ahead and used it on an EL34 pp amp...the owner liked it, B+ was around 440 volts...
 
BTW, can 6L6G be directly plug into an EL34 amp?

Have this Eico HF89 that uses EL34, pumping out 50 watts per channel.
UL design, 475v on plate @ 50mA.

Can you plug it in? Yes.
Should you turn it on? No.
The long list of 6L6 incarnations can be confusing.
Basically what you need to remember is that the 6L6 evolved over time.
The first versions are rated for 19W dissipation, max 360V on the anode and max 270V on the screen. These are the metal 6L6 and the glass 6L6G.
So if it is really a 6L6G you have, putting it in your 475V UL amp would run the screens 200V higher than their design spec.

Later versions had the same electrical characteristics, but higher ratings.
The last versions -6L6GC and 7581- are rated for 30W resp 35W and up to 500V. These can be used in your amp. If they would perform well depends on the circuit and transformers.
 
"Clean" is all relative.

The vast majority of the distortion of a valve head is probably coming from the really basic design of speaker cabinet, & non linear behaviour of the cone and magnet, but enabling you to carry it around with a 15" or 18" driver inside without having a hernia.

Yeah, I think people here don't understand guitar amps. None of.the amps I mentioned were separate head/cab 'stacks', they were all small 'combo' amps. None of.these combo amps have 15 or 18 inch drivers, only 8, 10 or 12 inch. Also, having played both tube and solid state versions of these combo amps, I know the actual amps sound different. You just reinforced my prejudices about what most people on this board know about guitar amps and music production (as opposed to reproduction).


Distortion is our way of life, it all depends which form you like most, and which is most socially acceptable.

Automotive technology is just the same.
We put 5L of gas in a modern high performance car, and throw 4.5L away into the environment in the form of heat, friction, noise, braking heat, & accelerating excess weight, then congratulate each other how advanced a society we have in the 21st century.

Agreed that tube amplification is a wasteful luxury, but far from waste on the scale of our dependence on internal combustion engines for personal transportation (imho).
 
Buy a voltmeter, solder some 10ohm resistors into the cathode circuit, and very gingerly turn it on if you insist on changing valves on what is aready a perfect working system.
Measure the Ik, and be ready to hit the off switch and in an instant! :D

Zekk didn't "insist" on anything. He asked a pertinent question to the thread, namely 6L6 vs. EL34 tube sound. Parafeed813 had a constructive, informative answer instead of your negative connotation.
 
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Even if guitar Related I don't know...or home audio...I can't make my mind up with either one...just different...I want to steer toward 6l6s sometimes though because to me yeah they come off as more Balanced/smoother...where EL34s just get aggressive real quick. It's Subjective I don't know how others hear things...
 
BTW, can 6L6G be directly plug into an EL34 amp?

Have this Eico HF89 that uses EL34, pumping out 50 watts per channel.
UL design, 475v on plate @ 50mA.

Just a note about the substituting these tubes from one to the other. On the 6L6 type, G3 is internally shorted with the cathode (pin 8). On the EL34, G3 is on pin 1 and cathode is separate at pin 8. So, when substituting 6L6s for EL34s, ensure that pins 1 and 8 are shorted at the sockets.

Pete Traynor did some funky things with G3 on EL34s to squeeze more power out of them.

Cheers
 
No way try to run 6v6s or 6l6Gs with voltages like that/that high, it isn't going to fly for long...a few people that ran certain 6v6s really high though, pretty sure they knocked down the screens though big time.
Later old stock GTAs some of them will handle the voltages for awhile though, but mostly tops 400-430v plates/screens. I pushed some Sylvania GTAs to 440-450v a few times. 400-430v absolutely cooks the old 6v6s though and sounds damn good doing it too xD
 
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Yes, Virginia, it's a beam tetrode.

More generally, if in doubt check the Duncan Amps tube data sheet locator. e.g. 6L6

<div class="polemic">triode strap the suckers for HiFi</div>

As done in 1949 - 807 PP on Bonavolt's pages.

Yes, you'll only get 15W rather than 50W but that's only 6db.

If you can find suitable UL iron, try this one from the Fi Primer (yes, they both say 807 but that's just a 6L6 with a different package.
807 Push-Pull Ultralinear
20 Watts at 0.1% HD Class A Tetrode OPT XFMR: 5K -7K
This is an interesting amplifier that uses a clever combination of subtle tricks to get tremendous performance from a simple design. The mix of positive and negative feedback with screen grid feedback, the cross-coupling of the transformer secondaries with the cathodes of the output stage higher current/lower voltage operating point insure wideband linear amplification, low phase shift, and low output impedance. 807s are a strangely overlooked output tube. Why, I really don't know. So many crappy amps have been made with 7868's,8417's,6LF6's,KT90's,KT-99's, and KT-100's etc.; i.e. really weird tubes (Barkhausen plates anyone?) The 807 on the other hand has no quirks other than its simplicity and reliability. It has class A operation good to the low mhz range and a plate dissipation of 25 watts. The tubes are plentiful and inexpensive. What more can one ask of a beam tube? This amp will hold its own against any "high end" pentode amplifier regardless of cost.
 
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I know, there must be hundreds of such discussions everywhere, but they all seem to be regarding guitar amps where the interest is in distortion characteristics. I need to know the subjective and the objective differences between the two, especially in SET application.

Any subjective listening opinion on the qualitative differences?

What should I know about the technical differences to build a SET amp around them?

Thanks


The subjective descriptions you hear about the sound of these tube types tells you something important which is based on objective facts. The EL-34 is often described as being "brittle" or having "more detail", and the 6L6 is "flat" or "lacks bite" or "is neutral".


All these impressions come from the fact that the 6L6 is actually a more linear tube with less distortion than the EL-34. There is something altogether "wrong" with true tetrode and pentode tubes using grids for screens. RCA got it right with the beam forming plates and designed a lower distortion tube. If you want clean hifi sound, stick with 6L6, 6550, real 6CA7s - stay away from all the KTs, EL-84 and EL-34.



The 6V6 is an oddity and has high-THD too.
 
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All these impressions come from the fact that the 6L6 is actually a more linear tube with less distortion than the EL-34.

Do you have a source for this claim? Philips claims otherwise (source: pages 307-310 of "Toepassing van de electronenbuis in radio-ontvangtoestellen en versterkers", Deel V, Philips, 1951: Philips Electronenbuizen Boek V 1951 ). But as the inventor of the pentode Philips could be biased…

RCA got it right with the beam forming plates and designed a lower distortion tube.

The beam tetrode was not invented by RCA but by EMI (British).
 
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