6V6GT vs. 6L6GC

[Cathode Ray]

What are the differences between 6V6GT and 6L6GC

I know the "L" is the more powerful tube (about 20 watts)

The "L" also has stronger bass.

Can I put "L"s in an amp designed for "V"s without other changes ?

Will it stress the OT/PT ?


Thanks

[Guy77]

Hi, the 6v6 tube puts out about 12 watts while the 6L6GC puts out about 30 watts per tube and so yes the 6L6 can stress your transformers.
You would need to check the specs of your transformers before making the swap.
Also the Bias for your power tubes would have to be changed to accommodate the 6L6 tubes.
Your 6v6 tubes probably have a 6.6K primary OT while the 6L6 likes a 4K but you can also run your 6L6 with a 6.6K primary OT as long as its a hefty one and not a light 2 lb one.
My suggestions above are for a push pull style amp (2 x6L6 tubes)

I am sure many others with more insight than me while chime in.

Cheers

Guy

[Cathode Ray]

Hi, the 6v6 tube puts out about 12 watts while the 6L6GC puts out about 30 watts per tube and so yes the 6L6 can stress your transformers.
You would need to check the specs of your transformers before making the swap.
Also the Bias for your power tubes would have to be changed to accommodate the 6L6 tubes.
Your 6v6 tubes probably have a 6.6K primary OT while the 6L6 likes a 4K but you can also run your 6L6 with a 6.6K primary OT as long as its a hefty one and not a light 2 lb one.
My suggestions above are for a push pull style amp (2 x6L6 tubes)

I am sure many others with more insight than me while chime in.

Cheers

Guy

Thanks guy!

I figured as much regarding the OT when I looked up the power ratings.

[Tony Bones]

I wouldn't worry too much about the OT, but be aware that the 6L6 draws twice the heater current; 0.9A vs 0.45A per tube.It's not always a big deal, but if you're talking about a 64 Princeton Reverb then you might want to be cautious. The PT's on those are a little on the small side to start with.

[Cathode Ray]

I wouldn't worry too much about the OT, but be aware that the 6L6 draws twice the heater current; 0.9A vs 0.45A per tube.It's not always a big deal, but if you're talking about a 64 Princeton Reverb then you might want to be cautious. The PT's on those are a little on the small side to start with.

Was thinking of using that as a test platform, but I may build from the ground up.

Trying to decide.

Might just use the '64 as is and see.

[xtian]

The notion that one tube or other has stronger bass is incorrect. Tubes don’t have an EQ curve.

[Cathode Ray]

The notion that one tube or other has stronger bass is incorrect. Tubes don’t have an EQ curve.

Sonically, is there any difference between a 6V6 and a 6L6 ?

[tubeswell]

The notion that one tube or other has stronger bass is incorrect. Tubes don’t have an EQ curve.

Sonically, is there any difference between a 6V6 and a 6L6 ?

Quite a lot. 6L6s that are run at optimum operating voltages require more bias voltage, so they run cleaner/more headroom, all other things being equal. In a tweed bassman (with 2* pre-amp stages before a LTP inverter), they will run a lot cleaner than 6V6s.

* the direct-coupled pair driving the tone stack, only has the overall gain of a single stage. (The input stage is the other stage). A LTP inverter has about 1/2 the gain of a normal inverting gain stage. - so that's '2 &1/2' gain stages. This will easily overdrive a 6V6 grid, but a 6L6 grid will stay cleaner longer

Their higher heater current draw, means they run hotter cathodes, so they deliver more tube current = more power for given voltage. If you run them optimally, you need PT and OT to be adequately rated for the power they will see.

The higher current and bigger output transformer means more bandwidth is present.

More headroom and more bandwidth = sonic differences. If you want a great-performing loud bassman amp, then use 6L6s

[xtian]

The notion that one tube or other has stronger bass is incorrect. Tubes don’t have an EQ curve.

Sonically, is there any difference between a 6V6 and a 6L6 ?

See tubeswell's answer, above. But note that he's talking about tubes IN-CIRCUIT, and not as standalone components. To rephrase, individual tubes have no particular "sound" until they're coupled with other components, and it's the complete circuit that defines the sound.

[Cathode Ray]

The notion that one tube or other has stronger bass is incorrect. Tubes don’t have an EQ curve.

Sonically, is there any difference between a 6V6 and a 6L6 ?

Quite a lot. 6L6s that are run at optimum operating voltages require more bias voltage, so they run cleaner/more headroom, all other things being equal. In a tweed bassman (with 2* pre-amp stages before a LTP inverter), they will run a lot cleaner than 6V6s.

* the direct-coupled pair driving the tone stack, only has the overall gain of a single stage. (The input stage is the other stage). A LTP inverter has about 1/2 the gain of a normal inverting gain stage. - so that's '2 &1/2' gain stages. This will easily overdrive a 6V6 grid, but a 6L6 grid will stay cleaner longer

Their higher heater current draw, means they run hotter cathodes, so they deliver more tube current = more power for given voltage. If you run them optimally, you need PT and OT to be adequately rated for the power they will see.

The higher current and bigger output transformer means more bandwidth is present.

More headroom and more bandwidth = sonic differences. If you want a great-performing loud bassman amp, then use 6L6s

Great! Many thanks!

This is exactly the kind of help I was looking for.

[norburybrook]

I built a Tweedle Dee last year and put in 6L6's it's become a very nice amp indeed, very loud and full sounding. I was surprised at what a great amp this is with 6L6's and with the NFB switch, a separately voiced 'mic' channel it has becomes a very versatile machine. Swapping back to 6v6's is easy if required.


M

[pdf64]

the 6v6 tube puts out about 12 watts while the 6L6GC puts out about 30 watts per tube and so yes the 6L6 can stress your transformers...

If the 6L6GC has a 30 watt plate then under the same 'design max' rating system, the 6V6 has a 14 watt plate. The 12 watt rating is under the 'design center' system.
http://frank.yueksel.org/sheets/127/6/6V6GTA.pdf
https://bms.isjtr.ro/sheets/135/6/6V6GTA.pdf
https://bms.isjtr.ro/sheets/093/6/6L6GC.pdf

A 6L6 would only stress the 6V6 amp's OT primary / PT HT winding if it was idled hotter than would be appropriate for a 6V6; an amp's signal power output is mainly determined by the OT primary impedance and HT voltage. Assuming that the amp is properly designed, unless the primary impedance is changed or the HT voltages raised, a 6L6 can't pass more current, hence neither the tube nor amp can put out more watts.

Regarding the tonal differences, from the afore-linked info, note that 6V6 have about twice the (forward biased) control grid and plate resistance of 6L6; the g1-k diode being by far the most significant clipping stage in a regular tube guitar amp, and the interaction between the amp's output impedance and speaker's freq-impedance characteristics being, outside of any obvious tone control circuitry, perhaps the most significant tone shaping aspect of a rig.