Easy Little 6L6 SE

[oldschooltube]

A while ago I was just poking around on the net and ran across this schematic for a 6L6 SE amp at Single Ended Tube Amp project [/URL]

I got bored and started building it one afternoon and just finished it a few days ago and I have to say that for such a simple little circuit it sure sounds great! I just wanted to post about this to share this with those of us who know their way around a schematic and understand how tube circuits work but are by no means "Tube Gurus". It was a fun weekend of soldering point to point and tweaking things around.

Anyway, I recommend this for anyone who wants to give point to point SE a try.

May all of you have a very happy and safe holiday season!

 

[HollowState]

The laminations of your output transformers look like they are arranged for push-pull (no gap), unless there is something about them that I don't know or can't see. Comments?

 

[oldschooltube]

Actually the output transformers are underneath the top plate. Those transformers on the top are the HV on the sides and the filament in the middle. Each channel has its own independent B+ supply.

 

[HollowState]

Ah....that explains it.

 

[TubeHead Johnny]

The 200 ohm cathode resistor seems a little low to me for a 6L6.

 

[azazello]

The 200 ohm cathode resistor seems a little low to me for a 6L6.

But You can use no more 300 ohms.

 

[DAK808]

Hi, i would like to use a 7591 tube for this circuit. Would you know what kind of changes in component values would be necessary? The B+ will be 320v. thanx in advance, Dak

 

[Eli Duttman]

The 7591 is a different "kettle of fish". Its drive requirements are much lower that those of the 6L6. Small signal circuitry usually associated with EL84s and 6V6s is appropriate for driving 7591s.

 

[cristi68p]

Wattage of the resistors

Hello,

I want to try this schematic also , as my first tube amp.
Please post also one power supply schematic without choke (if it is posible).
And what wattage are the resistors ? It is OK with 0,5 W?
Except the 200 Ohm resistor,whitch is 20W according schematic.

Regards,

 

[knockbill]

I am building a version of this amp also, with 1/2W resistors, except for any that are specified larger, with no problems... Using a tube (5U4) PS, and gas regulators for the output screens...
I noticed the OP closed the website...

This is a pretty old thread....
Regards,
John

 

[cristi68p]

Thanks John for your reply.A little bit late answer,the amp is already finished.And sounds wonderfull also !!!
Now I will build a PS for it using 5U4G tube.

 

[knockbill]

What did you use for OPTs? What is the SS PS you are using? Is it homemade?
Here is one channel, and the PS I'm working on... sounds like it has potential,,, I need a larger PT...
Regards,
John

 

[cristi68p]

For OPT I used this:
Ausgangsübertrager - Artikeldetailansicht - Trafobau- Troisdorf
You can use a larger OPT,the amp has muuuuch potential !!
As SS power supply,I used the same (almost the same) schematic as from the site I found this tube amp:
Single Ended Tube Amp project
But not a voltage doubler.
And I used a 10H choke.

Regards,
Bogdan

 

[knockbill]

Thank you for replying,,, I am currently building the SS PS from that site,,, Just wanted to try it, but will use tube PS, when I find a larger power transformer...

Yes, this little amp will sound very good, with a little tuning ...

Regards,
John

 

[cristi68p]

Yes,I also want a tube PS for this amp.
As a PT I used this one:
Toroid Transformer T120 110W 0 220 260 280 320V 0 1A X2 | eBay
It works perfect with my (homemade) SS power supply,but I wonder if it can support the 5U4G tube because it is rated at 5V@3A,and the 5U4G needs exactly 3A for heater.....so the maximum for this PT.
I am afraid of overheating.....but I will found out soon.Maybe this weekend,because the tube rectifier just arrive this week...🙂

Regards,
Bogdan

 

[HMV130]

Could anyone be so kind to tell me if OPT of 80mA and Power transformer of 120mA would be sufficient for this circuit?

 

[DAK808]

If you are sticking to just 6l6 the 80ma opt would be ok. But, this circuit would also support higher output 6l6 like 5881, 7581 with 15watt opt. and even 6550 if you allowed extra heater current. Of course your power trans would need to be at least 200ma B+ capable.

 

[HMV130]

If you are sticking to just 6l6 the 80ma opt would be ok. But, this circuit would also support higher output 6l6 like 5881, 7581 with 15watt opt. and even 6550 if you allowed extra heater current. Of course your power trans would need to be at least 200ma B+ capable.

Yes, I forgot to specify the tube. I'm intended to use a 6L6GC. Moreover I did not managed to precisely determine the impedance of the OPT in order to minimise the distorsion. 4200 according to the GE datasheet with 350v at the plate?

 

[DAK808]

Well, a 6l6gc would output 7 to 10 watts depending so that might take your output transformer into saturation at full steam. If you build your amp with a 6l6gc in mind and not exceed the 80ma rating of the opt you should be ok.