I built a Single ended 6L6 amp and I absolutely love the sounds both clean and overdriven.
A 12ax7 into a 6L6 design.
I put a 1000hz sine wave through it and measured 5.5v AC at the speaker jack before the sine wave started clipping.
I want to get to 10v before the sine wave starts clipping.
Can a parallel Singled ended set of 6L6 tubes get me there?
I understand I will need a huge output transformer for that.
Thanks
Guy
Single ended 6L6 Demo video
Moderators: pompeiisneaks, Colossal
Single ended 6L6 Demo video
Last edited by Guy77 on Fri Jun 30, 2023 3:05 pm, edited 1 time in total.
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Stevem
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Re: Parallel Single ended 6L6 maximum output
5.5 volts into what test load resistance?
5.5 volts is not even 4 watts into a 8 ohm load.
What is the peak wattage you see?
What is your plate and screen voltage ?
How much does your plate and screen voltage dip down at peak watts?
A common good set up will do 9.5 watts .
Yes a Ot to handle more then 8 to 10 watts will be big and expensive.
5.5 volts is not even 4 watts into a 8 ohm load.
What is the peak wattage you see?
What is your plate and screen voltage ?
How much does your plate and screen voltage dip down at peak watts?
A common good set up will do 9.5 watts .
Yes a Ot to handle more then 8 to 10 watts will be big and expensive.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Parallel Single ended 6L6 maximum output
Hi Steve, I am running this into an 8ohm load.Stevem wrote: ↑Mon May 29, 2023 8:27 pm 5.5 volts into what test load resistance?
5.5 volts is not even 4 watts into a 8 ohm load.
What is the peak wattage you see?
What is your plate and screen voltage ?
How much does your plate and screen voltage dip down at peak watts?
A common good set up will do 9.5 watts .
Yes a Ot to handle more then 8 to 10 watts will be big and expensive.
The 6L6 plate and screen is at 315v and 6L6 is cathode biased at 77ma
There is 20v across my 270ohm cathode resistor.
I am running the 6L6 at about 75% bias.
My wall voltage is 116v
I never measured how much the voltages are dipping at maximum wattage but I will check it when I get the amp back from the studio.
I think that is what is happening since my PT is a Hammond 270DAX and its rated at only about 100ma.
The amp sounds great I just wanted a little more wattage. 8- 9 watts would be perfect!
Cheers
Guy
Last edited by Guy77 on Mon May 29, 2023 10:06 pm, edited 1 time in total.
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Stevem
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Re: Parallel Single ended 6L6 maximum output
A Hammond 270dax is a filiment transformer, not a single ended OT.
According to 6L6 design specs
And for 10.8 watts the plate voltage should be 350, the screen 250 and the tube should idle at 54 mil amp and at peak wattage it should be pulling 66 ma.
Is that a used 6L6?
According to 6L6 design specs
And for 10.8 watts the plate voltage should be 350, the screen 250 and the tube should idle at 54 mil amp and at peak wattage it should be pulling 66 ma.
Is that a used 6L6?
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Parallel Single ended 6L6 maximum output
Thanks for the update Steve. I am using a new Groove tube 6L6GC that is a rebranded JJ.
My OT is a Hammond 125ESE. I am running it at 5K primary winding into 8 ohms.
I will look to increase the plate voltage with a different Power transformer.
That will be cheaper and lighter than running 2x6L6 in parallel with the larger transformers required.
No wonder there are so few 2x6L6 SE amps out there.
Cheers
G
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Stevem
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Re: Parallel Single ended 6L6 maximum output
Yes your good with that OT, but it’s that low B+ that’s killing you!
My BF Champ with a 6V6 puts out more power then your set up.
These Champ run well over 350 volts .
Keep in mind that basically volts x current =
Watts.
My BF Champ with a 6V6 puts out more power then your set up.
These Champ run well over 350 volts .
Keep in mind that basically volts x current =
Watts.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Parallel Single ended 6L6 maximum output
one 6l6 will like more 2k5-3k than 5k load, and the power will go up..
no problem in paralleling output tubes in SE.. just change OT for one 1k5-2k and cca 160mA primary current, also PT must handle double current so this need to be checked too
no problem in paralleling output tubes in SE.. just change OT for one 1k5-2k and cca 160mA primary current, also PT must handle double current so this need to be checked too
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Stevem
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- Location: 1/3rd the way out one of the arms of the Milkyway.
1 others liked this
Re: Parallel Single ended 6L6 maximum output
And x2 the heater current also.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
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johnnyreece
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Re: Parallel Single ended 6L6 maximum output
FYI - Weber sells reasonably priced heavy-duty SE OTs. Here's their 25W: https://www.tedweber.com/wse25/. It's just over $50, but that's not out of line for what it is. Their 15W is out of stock at the moment.
Re: Parallel Single ended 6L6 maximum output
Thanks for the info everyone! I will look into experimenting with different transformers.
So far I am happy with it but there is definitely room for improvement with all the info you have provided.
I see Hammond has the 1627 single ended that handles 160 - 200ma I think but it weighs 11lbs and is $250cdn.
No wonder there are so few 2x6L6 single ended. The single ended tone is great and I see the reason they produce them!
Will post audio tracks once I get the amp back.
Cheers
Guy
So far I am happy with it but there is definitely room for improvement with all the info you have provided.
I see Hammond has the 1627 single ended that handles 160 - 200ma I think but it weighs 11lbs and is $250cdn.
No wonder there are so few 2x6L6 single ended. The single ended tone is great and I see the reason they produce them!
Will post audio tracks once I get the amp back.
Cheers
Guy
Re: Parallel Single ended 6L6 maximum output
there is a more thing to take care, not only PT, OPT/
not too much people known that for avoiding oscillations every tube in parallel must have, separate cathode resistor and cap in paralell (or separate bias), separate grid stopper, anodes can be connected together
you can start with wrong fender idea of simple paraleling ECC81 for the reverb driver... cannot be more wrong to do that, for output tubes is even more important
not too much people known that for avoiding oscillations every tube in parallel must have, separate cathode resistor and cap in paralell (or separate bias), separate grid stopper, anodes can be connected together
you can start with wrong fender idea of simple paraleling ECC81 for the reverb driver... cannot be more wrong to do that, for output tubes is even more important
Re: Parallel Single ended 6L6 maximum output
Ran the same test with my new TRMS Fluke 115 meter and got a higher reading. TRMS meters do make a difference when reading AC voltage!
This time I went slightly over 7 volts before the sine wave started to distort. It topped off at 8.8v with a square wave,
Before the non TRMS older meter was reading only 5.5v.
This was with the 5k primary on the OT. I will try it with the 2.5K tap tonight and see what the difference is.
This was with a single 6L6GC power tube.
I was pleasantly surprised at how loud 7 v AC of clean headroom actually sounded for home use!
Circuit here is an Overdrive Special with Classic tone stack.
Guy
This time I went slightly over 7 volts before the sine wave started to distort. It topped off at 8.8v with a square wave,
Before the non TRMS older meter was reading only 5.5v.
This was with the 5k primary on the OT. I will try it with the 2.5K tap tonight and see what the difference is.
This was with a single 6L6GC power tube.
I was pleasantly surprised at how loud 7 v AC of clean headroom actually sounded for home use!
Circuit here is an Overdrive Special with Classic tone stack.
Guy
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Stevem
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Re: Parallel Single ended 6L6 maximum output
A single 6L6 in class A wants about a 5k load and if you half it you will be running the tube very hard !
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Parallel Single ended 6L6 maximum output
Thanks for the update Steve. I actually like how it sounds with the 5K primary too. I will leave it hear and save my tube life too.
Just so that everyone knows I am actually running the JJ 6L6 here at 80% bias so there is actually room to get more output out of this circuit.
I am really impressed with how fast the attack is and how nice and open sounding a single ended amp is. If anyone hasn't tried one they definitely need to experience it!
Guy
Just so that everyone knows I am actually running the JJ 6L6 here at 80% bias so there is actually room to get more output out of this circuit.
I am really impressed with how fast the attack is and how nice and open sounding a single ended amp is. If anyone hasn't tried one they definitely need to experience it!
Guy
Re: Single ended 6L6 Demo video
Thought I would share a video of the finished product. Happy how this turned out.
Its running the classic tone stack and high plates on the preamp tubes. I switch on the Overdrive channel at 55 sec mark.
Its running a single JJ 6L6GC here and the 2 preamp tubes are 12ax7. I wrapped it in black suede.
I added a Line out jack with level control and a dummy load on 16ohm jack for the customer.
Its the owner in the video.
Happy long weekend everyone!
https://www.youtube.com/watch?v=shD1Qcw9w64
Cheers
Guy
Its running the classic tone stack and high plates on the preamp tubes. I switch on the Overdrive channel at 55 sec mark.
Its running a single JJ 6L6GC here and the 2 preamp tubes are 12ax7. I wrapped it in black suede.
I added a Line out jack with level control and a dummy load on 16ohm jack for the customer.
Its the owner in the video.
Happy long weekend everyone!
https://www.youtube.com/watch?v=shD1Qcw9w64
Cheers
Guy
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