Anyone done a PI driver with 6V6's?

[FUCHSAUDIO]

Thanks for the info. At some point, I'll get back into looking at that. There's an ODS-II (c) and TDS-II (c) (lol) somewhere in the pipeline upstream, and maybe I can explore that when the R&D gets underway.

Thanks for the nod on the trademark...truly all good, just don't put it on a product...

[wjdunham]

Thanks for the info. At some point, I'll get back into looking at that. There's an ODS-II (c) and TDS-II (c) (lol) somewhere in the pipeline upstream, and maybe I can explore that when the R&D gets underway.

Thanks for the nod on the trademark...truly all good, just don't put it on a product...

Of course not Just having some fun.
Bill

[FUCHSAUDIO]

You would be amazed at how some people simply don't research these things, or get all testy (or ignore you) when you bring it to their attention. A simple internet search is really all it takes. Mentioning it in a forum doesn't matter. It's products being sold which matter.

Honestly, it's all about business, nothing else. Not busting anyone's balls. I never even thought about stuff like that when I started my business.

In the past, Peavey and Mesa contacted me. I wrote a simple letter which acknowledged the error, and that a change would be made. That's all it took to move on. Hartley and I spoke on the phone. He wanted me to know he didn't want to be known as "some guy who just sues people because he can". Randall Smith stopped by my NAMM booth and made mention, followed by a letter.

[wjdunham]

You would be amazed at how some people simply don't research these things, or get all testy (or ignore you) when you bring it to their attention. A simple internet search is really all it takes. Mentioning it in a forum doesn't matter. It's products being sold which matter.

Honestly, it's all about business, nothing else. Not busting anyone's balls. I never even thought about stuff like that when I started my business.

In the past, Peavey and Mesa contacted me. I wrote a simple letter which acknowledged the error, and that a change would be made. That's all it took to move on. Hartley and I spoke on the phone. He wanted me to know he didn't want to be known as "some guy who just sues people because he can". Randall Smith stopped by my NAMM booth and made mention, followed by a letter.

Not getting too far off the topic of the thread, but I agree completely Andy. This business is tough enough, I've always felt cooperation is far better approach than confrontation.
Best,
Bill

[vibratoking]

...At some point I plan to do an SSS #004 build...

So you have a good schematic for SSS #004?

[FUCHSAUDIO]

Not getting too far off the topic of the thread, but I agree completely Andy. This business is tough enough, I've always felt cooperation is far better approach than confrontation. Best, Bill

I try to remain friendly with both the little and big builders out there. Ya have to see these people at amp shows and NAMM shows......why not just get along ?

[vibratoking]

It doesn't appear that any of the trademark infringement arguments made in this thread are valid.

Now how about that SSS #004 schematic?

[Structo]

Come on guys, don't ruin this great thread with petty bickering.

If you guys want to have words with each other, use the private message or email function.

[Max]

AFAIR and AFAIU many members here refer to all the different inverter /driver configurations you find in Dumble amps in some generalizing way by always calling them "cathode follower" ("CF") configurations.

I understand this "cathode follower" label in regard to the inverter /driver configurations you see e.g. on the pictures of SSS #001 and #002 and on the hand drawn schematic of SSS #002.

But can someone here explain why it’s obviously thought to be correct here calling other inverter / driver configurations perhaps more similar to the 12AU7 / 12BH7 configuration shown on the attached schematic - that AFAIK you'll find in other Dumble guitar amps and Dumble bass amps, too, and not only in the Odyssey series - a "cathode follower" or "CF" configuration?

Source: https://tubeamparchive.com/viewtopic.ph ... 153#219153

Cheers,

Max

[vibratoking]

But can someone here explain why it’s obviously thought to be correct here calling other inverter / driver configurations perhaps more similar to the 12AU7 / 12BH7 configuration shown on the attached schematic - that AFAIK you find in other Dumble guitar amps and Dumble bass amps, too, and not only in the Odyssey series - a "cathode follower"or "CF" configuration?

Good point Max. I can't explain why it is thought to be correct. I don't think anyone else can offer a valid explanation either. I think a mistake was made in the thread you referenced, so the explanation would be 'oops'. The 12BH7 is NOT a cathode follower/CF and it is incorrect to refer to it as one.

[Max]

I think a mistake was made in the thread you referenced

But AFAIR similar 12AU7 / 12BH7 driver / inverter configurations you'll find in many Dumble amps for guitar and bass. And AFAIR all the 12AU7 / 12BH7 inverter / driver configurations in Dumble amps have been always called "cathode follower" circuits here, and not only in this Odyssey thread? Or do I remember wrong?

Cheers,

Max

[FUCHSAUDIO]

It does seem odd. In-fact, it's a a diff amp followed by an anode follower. Who knows why it evolved into being called something else...

[Bear]

I think people familiar with the CF driver schematics and the similar Ampegs might have assumed schematic errors or may just not have looked closely. Perhaps the difference in tube choice between the two configurations make more sense when accounting for the different configurations. (Or did the tube choice cross over?)

[vibratoking]

...In-fact, it's a a diff amp followed by an anode follower...

I beg to differ. I agree, the first stage is a diff amp. But, calling the next stage an anode follower is not correct. It is an inverting gain stage. The output is inverted, so it cannot be considered/called a follower. Even if it was setup to have a gain of -1, it would not be following because of the inversion. This is more properly called a common cathode configuration. Also, the common cathode output impedance is much higher than that of a follower.

[FUCHSAUDIO]

You say tomato...lol.

I think of it as a "follower" mostly as it reduces output impedance and adds gain as a perk. It's semantics imho.

I have to find some time and map both out. I'm sure they clip and respond differently. Advantage of the CF arrangement is the loss of the coupling cap, improved low end tightness, reducing Miller effect and increasing overall amp clarity. I suspect (but don't know for certain) that the other circuit might clip a little smoother, but you still have the coupling cap on the way to the power tubes...Mesa used that style in some of their bass amps. Marshall used it in their rack mount power amps.