output tube changeout

[Rohbiwan]

I’m putting together a Two Stroke using tubes and mostly components I already possess (I own an old electronics shop, though geared more towards hifi). I was going to use the 6l6 option, but am unsure if there is a wiring difference at the socket between the 6L6 and the 6v6s.

If this topic has already come up, please post a link.

This looks like a fun site and good resource, thanks in advance for the help.

Bill

[Andy]

There is no wiring difference on the tubes. The Two Stroke is really flexible that way. You can use the 6V6, 6L6, KT66, etc. with no change to wiring or bias. The only thing that changes is the impedance, so you will want to make sure to match it via the switch in the instructions. That same switch will allow you to use either a 4Ω or 8Ω load so I wouldn’t recommend omitting that switch. Though you could if you were going to lock down a certain output configuration.

I will post the impedance “chart” on the wiki page so that it is easily accesible.

[joewilly]

I am new to the TAN site and I just completed a 2 Stroke amp. If you have not read Dave Hunters book The Guitar amp handbook you should. The book is a valuable resource. And the beauty of the 2 Stroke amp is that
you can change power tube using the list of recommended power tubes.
I do not have any electronic background and I was able to complete the 2 stroke amp and it actualy works. Saying that, it says a lot for the simplicity and unique character of the 2 stroke amp.

Lots of luck with your project

[Andy]

Here is a link to the impedance chart if you want to print it and stick it on the amp somewhere. It is also in the Wiki now.

https://www.tubeampnetwork.com/images/impedance_chart.png

[Rohbiwan]

Wow, you guys rock!

I do have Hunters book, just finished it and am now running through the power supply book by, forgive me for not remembering the name, Belencoe I believe. As I am a middle age guy back in college for calc, the book comes at a great time.

Thanks for the chart as well

[Andy]

Make sure you check out the Wiki page. We have the addendum to the book instructions there as well. It corrects some of the values and details some other changes including going down to 1 tube. Having 2 power tubes really doesn’t bring much to the table at the end of the day. Most of us build based on the addendum and do a single tube build.

[Robin]

Be sure to use the updated, single output tube version of the schematic and layout, the original 2 output tube version from the book will only work with 2 6V6, although you could build the original 2 output tube version and use just one 6L6 (or other output tube) without over-taxing the transformer. Read DH’s addendum as it addresses some vague layout issues in the book.

Andy’s impedance comments apply to the output transformer secondary’s (speaker load).

Merlin Blencowe’s books are the best. If you read those, 2stroke mods are sure to follow

Good luck, it’s a neat design

[Rohbiwan]

Continuing…

As I collect parts from my warehouse and order what I lack, I find that I have a Hammond 290CX power transformer

This transformer is 5V shy which I would think is close enough, and current looks good, but my lack of experience has me askin’ those with experience, if you don’t mind. Will this transformer make a suitable sub.

Thanks,
Bill

[Robin]

That looks good, it even has a center tap for the heater circuit.

[Rohbiwan]

Good news on the PT.

Having now read the entire two stroke wiki, I realize my original question was answered there, so thanks for being patient with me.

I purchased a majority of the parts for the two stroke from one of your recommended sites, Amplified parts, and they did a fabulous job. Ordered enough to make 4 sets of electronics on Wednesday and received the product today – 2 days later. As I sit here making 5w supervised sound amps for PA, all I can do is stare at my bag-o-goodies. Thanks for the great two stroke page.

[Rohbiwan]

[attachment=65]Turretboardtan2stroke.jpg[/attachment]

Step 1: create the turret board. note to self: long sleeves and gloves are required when cutting this board.

[Andy]

Yeah…. let us know when you stop itching and can keep building

[Robin]

I usually score and break it, or use a long blade paper cutter. I wear a dust mask when I sand the edges smooth.

[Rohbiwan]

After a work injury – my first in over 25 years commercial work, I have had my equipment brought home and gotten restarted on the amp.

just for the build record – here is the board assembled, if anyone notices anything odd, please let me know. This board is a little over sized as I plan to build four of them making improvements along the way.

[attachment=66]ttsboard2.jpg[/attachment]

I did note in another thread that there was talk a cabinet drawing in the future. That would be very helpful and I would be thankful to see such a drawing.

Have a great New Year everyone.

[Rohbiwan]

[attachment=67]testingwithtubes.jpg[/attachment]

Got her assembled, but no sound yet. It’s late so I’m waiting til I am more alert. Heaters light up, but I suspect my voltage may be a bit high. What voltages should I be seeing at A, B and C? If anyone knows that is. This 5Y3 seems to be quite efficient.

Thanks,

Bill

[Author]

Posts