6L6 vs EL34 - Page 2

anatech · 9th October 2004, 11:53 PM

Hi resident,
I find that at 450V, cheap 6L6GC's may run into problems. I'm sure there are many good brands out there, but from personal experience I've started to use Electroharmonix 6L6EH. They have a plate area similar to KT-66 and survive Fender twins. Sovetek's will fail for sure in those, as do many others. No sound problems over NOS units I have either. If you are using 12AX7A's, you will find the 12AX7EH's to be very quiet on average. These are a pretty good place to start.
-Chris

resident · 10th October 2004, 05:18 PM

I'm planning to go with svetlana.SV 6L6GC.What do you say about these?
About Sovtek 6L6WXT+ ???

anatech · 10th October 2004, 06:40 PM

Hi resident,
My own experience has been okay with Svetlana's products and okay with Sovtek at lower voltages. The Electroharmonix product has been a fair bit better than the Sovtek product. Same supplier (New Sensor in NY). I'd be deciding between Svetlana and Electroharmonix.
I think the most important things to buy are the output transformers, power transformer and the chassis. Make sure to leave room around the output tubes. Ventilation holes in the chassis will help cooling further. I prefer chassis mounted sockets. PCB's + heat + high voltage don't get along to well.
Start building with quality parts & enjoy!

-Chris

resident · 10th October 2004, 09:45 PM

Hi anatech,

I'll go with Svetlana.Preamp tubes, I'll go with 6H8C (russian 6SN7).I found them at 10euro each.
About transformers I'll buy from a local winder that I believe are very good.Better than Hammond!At reasonable prices.
Chassis, 2.00-2.50mm aluminium with wooden base.
Of course, I'll go point-to-point wiring.I don't like PCBs.

About sovtek 6L6WXT+ aren't the same with 6L6EH?
My friend has two of them and he likes to build a P-P guitar amp.Maybe a Fender clone.
How much anode voltage do you believe is good to use with Sovteks?

anatech · 11th October 2004, 02:05 AM

Hi resident,
No, Sovteks are not the same as Electroharmonix. Totally different tubes. The 6L6EH is one of the few tubes that will consistantly survive Fender Twins or Mesa Boogie Barons. I'd watch taking the Sovteks over 400V. This doesn't mean they can't go higher, it just means that you should approach those voltages with caution. I have tried many. I've seen too many plates turn red quickly.
You might consider a metal base for shielding, you can put wood over it. Hammond manufacturing is local in my provence, lucky me. Fred Hammond was a very helpful man, as all his staff has been.
Sounds like you are off to a good start.
-Chris

gingertube · 11th October 2004, 07:57 AM

I note above that you intend to use Cathode Feedback - an excellent way to get good dampimg factor without resorting to large amounts of global feedback and suffering loss of image and crispness.

If you can beg, borrow or steal a copy of Menno van der Veen's "Modern High-End Valve Amplifiers" have a look at what he says about cathode feedback with real pentodes (the EL34) vs beam power tetrodes (the 6L6). The Ia vs Va curves (at each grid voltage) move to the left (that is you get higher Ia at the same Va) when using real pentodes - this doesn't happen with the beam power tetrode.

The EL34 is much easier to drive as you don't need such a low value grid 1 resistor. It also has a tidier turn on/off characteristic which helps if your design is Class AB1.

I believe that it also has a softer saturation which will help if you like things LOUD.

I'm part way down this track myself with a prototype amp built using VDV-2100-CFB/H Output Transformer - I settled on 4 x KT88 to drive it (a beam power tetrode) and cathode followers (6SN7) driving the KT88 grids.

Just another dabblers views - hope you find this useful.

Cheers,
gingertube

resident · 12th October 2004, 12:05 AM

I'm still a little bit

I think I'll go with 6L6GC.More power dissipation.So lower THD.
I'll choose EHX or Sovtek WXT+ (very similar with EHX-maybe same) for my first project.I can get them about 10euro/each instead of 20 for Svetlana.

@anatech
See at New Sensor about Sovtek WXT+.It looks same with EHX.

anatech · 12th October 2004, 01:25 AM

Hi resident,
I don't know. Maybe. I had a Sovtek go red quick, Electroharmonix okay every time. Plus the staff at New Sensor told me they were different tubes. But you never know at the end of the day, do you?
-Chris

resident · 12th October 2004, 07:52 AM

Hi anatech
At the beginning I thought you are talking about older Sovtek GCs.And NOT about WXT+.
I don't want at the end of the day-project to see a Sovtek go red quick.So,EHX.

Thanks

anatech · 13th October 2004, 01:47 AM

Hey resident!
Go build that thing. Once it's built you can modify it as you please. The journey is what's worth the trip.
-Chris

11th October 2004, 07:57 AM	#16
gingertube diyAudio Member Join Date: Oct 2004	EL34 vs 6L6 I note above that you intend to use Cathode Feedback - an excellent way to get good dampimg factor without resorting to large amounts of global feedback and suffering loss of image and crispness. If you can beg, borrow or steal a copy of Menno van der Veen's "Modern High-End Valve Amplifiers" have a look at what he says about cathode feedback with real pentodes (the EL34) vs beam power tetrodes (the 6L6). The Ia vs Va curves (at each grid voltage) move to the left (that is you get higher Ia at the same Va) when using real pentodes - this doesn't happen with the beam power tetrode. The EL34 is much easier to drive as you don't need such a low value grid 1 resistor. It also has a tidier turn on/off characteristic which helps if your design is Class AB1. I believe that it also has a softer saturation which will help if you like things LOUD. I'm part way down this track myself with a prototype amp built using VDV-2100-CFB/H Output Transformer - I settled on 4 x KT88 to drive it (a beam power tetrode) and cathode followers (6SN7) driving the KT88 grids. Just another dabblers views - hope you find this useful. Cheers, gingertube

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9th October 2004, 11:53 PM	#11
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi resident, I find that at 450V, cheap 6L6GC's may run into problems. I'm sure there are many good brands out there, but from personal experience I've started to use Electroharmonix 6L6EH. They have a plate area similar to KT-66 and survive Fender twins. Sovetek's will fail for sure in those, as do many others. No sound problems over NOS units I have either. If you are using 12AX7A's, you will find the 12AX7EH's to be very quiet on average. These are a pretty good place to start. -Chris

10th October 2004, 05:18 PM	#12
resident Account Disabled Join Date: Sep 2004 Location: Earth	I'm planning to go with svetlana.SV 6L6GC.What do you say about these? About Sovtek 6L6WXT+ ???

10th October 2004, 06:40 PM	#13
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi resident, My own experience has been okay with Svetlana's products and okay with Sovtek at lower voltages. The Electroharmonix product has been a fair bit better than the Sovtek product. Same supplier (New Sensor in NY). I'd be deciding between Svetlana and Electroharmonix. I think the most important things to buy are the output transformers, power transformer and the chassis. Make sure to leave room around the output tubes. Ventilation holes in the chassis will help cooling further. I prefer chassis mounted sockets. PCB's + heat + high voltage don't get along to well. Start building with quality parts & enjoy! -Chris

10th October 2004, 09:45 PM	#14
resident Account Disabled Join Date: Sep 2004 Location: Earth	Hi anatech, I'll go with Svetlana.Preamp tubes, I'll go with 6H8C (russian 6SN7).I found them at 10euro each. About transformers I'll buy from a local winder that I believe are very good.Better than Hammond!At reasonable prices. Chassis, 2.00-2.50mm aluminium with wooden base. Of course, I'll go point-to-point wiring.I don't like PCBs. About sovtek 6L6WXT+ aren't the same with 6L6EH? My friend has two of them and he likes to build a P-P guitar amp.Maybe a Fender clone. How much anode voltage do you believe is good to use with Sovteks?

11th October 2004, 02:05 AM	#15
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi resident, No, Sovteks are not the same as Electroharmonix. Totally different tubes. The 6L6EH is one of the few tubes that will consistantly survive Fender Twins or Mesa Boogie Barons. I'd watch taking the Sovteks over 400V. This doesn't mean they can't go higher, it just means that you should approach those voltages with caution. I have tried many. I've seen too many plates turn red quickly. You might consider a metal base for shielding, you can put wood over it. Hammond manufacturing is local in my provence, lucky me. Fred Hammond was a very helpful man, as all his staff has been. Sounds like you are off to a good start. -Chris

12th October 2004, 12:05 AM	#17
resident Account Disabled Join Date: Sep 2004 Location: Earth	I'm still a little bit I think I'll go with 6L6GC.More power dissipation.So lower THD. I'll choose EHX or Sovtek WXT+ (very similar with EHX-maybe same) for my first project.I can get them about 10euro/each instead of 20 for Svetlana. @anatech See at New Sensor about Sovtek WXT+.It looks same with EHX.

12th October 2004, 01:25 AM	#18
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi resident, I don't know. Maybe. I had a Sovtek go red quick, Electroharmonix okay every time. Plus the staff at New Sensor told me they were different tubes. But you never know at the end of the day, do you? -Chris

12th October 2004, 07:52 AM	#19
resident Account Disabled Join Date: Sep 2004 Location: Earth	Hi anatech At the beginning I thought you are talking about older Sovtek GCs.And NOT about WXT+. I don't want at the end of the day-project to see a Sovtek go red quick.So,EHX. Thanks

13th October 2004, 01:47 AM	#20
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hey resident! Go build that thing. Once it's built you can modify it as you please. The journey is what's worth the trip. -Chris

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