Power Scaling is Flawed?

[Steve Conner]

Hey Tiago, I'd be very interested to see that. I totally agree that putting B+ across a regular pot is a recipe for flaming death sooner or later. Your circuit sounds kind of like my Toaster regulator, but without the regulation. I never did figure out how to modify my regulator circuit to stop it regulating

Mooreamps, I watched some of your video clips on NoobTube and it certainly seems to work. Your amp seems to be getting a cool tone without being painfully loud. You mentioned EL34s and 6L6s, did you realy cram a pair of each into a Valve Jr. chassis? And what do all those blinking LEDs on the amp do?

[Tiago]

Steve, I will draw the schematic as soon as I can and I will try to post it here.

[mooreamps]

Mooreamps, I watched some of your video clips on NoobTube and it certainly seems to work. Your amp seems to be getting a cool tone without being painfully loud. You mentioned EL34s and 6L6s, did you realy cram a pair of each into a Valve Jr. chassis? And what do all those blinking LEDs on the amp do?

Steve,

Thank you for the kind words. I don't get many of them. I figure Mike was pushing maybe a couple of watts into that 2x12. On this amp, it's 18 watts single ended; one EL34 and one 6L6. The front panel lamps are called BITE lamps ; Built In Test Equipment. Tube current from each tube drives each lamp. If you lose a tube, either in the pre-amp or power amp, you know what tube is bad. If all the lamps are out, then it's something in the power supply.

-g

[Tiago]

GRAB THIS! My PowerChanger (semi?)tested circuit

The .pdf attachement is a circuit which might achieve a similar goal as KOC power scaling.
I can give a full explanation of the circuit, values etc if someone is interested.

I have to say that this is maybe "semi-tested" because I've done a pcb of it and while in test I've modified a somethings on the PCB but I don't know were I put the pcb and I'm too lazy to search for it to see the changes. Altough as far as I can remember all the changes I did are updated in this schematic (the "semi" part of it comes from the "as far as I remember"...).

In the B+ reducer part of it, you may see that mosfet (Q5) and the 2N3904 (Q4) and you might think that I could used just the mosfet (Q5), altough the "off" current of these mosfets are too high to be used with that 1M pull up resistor (R6), it would drop too much the voltage in the "highest" power setting and in the other hand, I couldn't find some cool high voltage NPN transistor that could be found in any store around the world. And also, I'm using there the 1M value because this circuit is should be transparent, it cannot take too much current out of the amp and I dont like hot things.

Other thing that I would like to ask is, how can I release this in a way that I protect it from being patented and to be avaiable to everyone just like opensource software?

[Tim Hall]

My guess is (but I'm certainly no expert) only the author (you) has the right to patent YOUR work. This is the case with copyrights, which I realize is different than a patent.

I would think the more you share your idea, in the spirit that it should be passed on, the harder it would be for a would-be patent thief to make any profit from it. Your post is probably the first good step in the right direction.

If I was smart enough with electronics, and could invent cool things, I'd share them too.

This might not be of any help. but: http://creativecommons.org/

[mooreamps]

My guess is (but I'm certainly no expert) only the author (you) has the right to patent YOUR work. This is the case with copyrights, which I realize is different than a patent.

I would think the more you share your idea, in the spirit that it should be passed on, the harder it would be for a would-be patent thief to make any profit from it. Your post is probably the first good step in the right direction.

If I was smart enough with electronics, and could invent cool things, I'd share them too.

This might not be of any help. but: http://creativecommons.org/

I have no problem sharing them with people I know. What I don't want to do it share my circuits with my competition ; aka Crate , Mesa, Carvin, Marshall, ect. This is why I only selectively share openly on a public forum. I already know a few of my details got leaked out onto the 18 watt forum. I strongly suspect the big boys watch that one.

-g

[Steve Conner]

Hi all,

Mooreamps, there's your advertising slogan right there... "amps that BITE"

Tiago, that circuit sure looks like it would work. I dug out the "Power Tweeking" circuit that I published back on the old Ampage, which I never tested at all, but it looks kind of similar too... If you want it to be open-source, I'd recommend the Creative Commons license too.

As for the big boys stealing your ideas, I've never been too worried about that. It seems to me that big companies like Marshall and Crate have far different goals and priorities than we do, when it comes to designing their amps. They have their own cutting-edge research programs, and after years of effort by brilliant engineers out came... the Valvestate series and the Crate Powerblock!

They obviously know what they are doing, because the Marshall and Crate SS amps can be assembled by robots on standard Chinese production lines, sell like hot cakes and actually sound fine in a gig or rehearsal situation. It doesn't seem to me that power scaling tube amps map well onto that.

But of course if you want to keep your ideas confidential that's fine too... I spend all day designing electronic equipment under a NDA.

[hasserl]

I strongly suspect the big boys watch that one.

I don't think so, I don't think they know boards like that and like this exist. They are far to self focused, and set their agenda's toward the mass market of Hot Rod Deluxe buyers.

They have their own cutting-edge research programs, and after years of effort by brilliant engineers out came... the Valvestate series and the Crate Powerblock!

LOL!! I have one of those Powerblocks.

Actually, I use it as a back up amp, I throw it into the car when I head to a gig in case I have an amp problem I can set it up quickly and get going again. I used to carry a seperate tube amp for that, but the Powerblock is so much more portable, with sound quality good enough to use in a pinch. May not be my first amp of choice, but as a back up it'll do fine.

[Tiago]

Steve, I remember that Power Tweak from the old ampage! Wasn't KOC involved in that discussion too? Mine is so similar to yours that one may call it as "suspiciously similar". But not, if I remembered of it and if I was based on yours it could save me lot's of time and work. At the time you posted it I didn't even know what Vbe was.... But thing that I would not agree is the bias part. Don't get me wrong, I'm not saying that that's junk, it isn't (actually its very clever and simple), but given the application I would prefer a bias supply that would "read" the actual B+ voltage and put out a voltage acording to that value not one that would be dependent on a setting. An example, if M1 blows up and shorts funny things could happen. Bias is a voltage that I dont wan't to be missing on someone amp.
You know, I used my circuit for some time but then I took it out... You know why?? Because, just like you, the main thing that I like about "cranked amp tone" is actually the volume! It didn't worth having one more thing in the bench (my amp was permanently on the bench...).
I know that your design is very "beta untested" but other thing that you might want to add is capacitors and protection zeners. It will make the Mosfets almost undestructible. I've had mosfets dying with oscillations and shorting themselves so capacitors are a must. Also the zeners to protect their Gate. Or you can improve mine that needs some non-linearity in the bias part and then we could release it under a CC license (considering both of us the autors).
Btw,my Iexplorer crashes on the CC site...yours too?

About the Big boys...have you read a manual of a Vox Valvetronix and are you aware of the KOC SuperScalers?
Vox Valvetronix amps look like solidstate SuperScalers driver by a 12A*7 mini poweramp.
I don't know if they copied some of KOC ideas, because those amps are in the marked before TUT5 I think.
But They (by saying they, I mean the conspirancy against us) might sometime be interested in this little gadgets and tecnhologies developed by "little people". I would not say Marshall or Fender, but M€sa and Peaveee fit more in that profile. Just look at the classical case of Slo100 and 5150 or Rectifrikingstein series.

[mooreamps]

Well, I sure hope that is the case. If the big boys are only concerned with doing development using solid state, that's fine by me. I want to keep my amps as simple and "old school" as possible. They may not know about this board, but I strongly suspect they were watching 18watt.com. Even this thread, are you beginning to notice how many hits this thread is getting ?

I am aware of Kevin's Super Scaler technology. I was even half way into my own verison of a Super Scaler until I got side tracked on bringing up a pre-amp circuit, and bought that first VJ chassis as a test bed.

Amps that bite, ya, probably not far from the truth on that one.


-g

[mooreamps]

Ya, Amps that Bite. Probably not too far from the truth. Anyway, I sent the print to your e-mail.

-g

[mooreamps]

I am aware of Kevin's Super Scaler design. I may build one in the future, but I'm not sure there is any demand for any guitar amp bigger than 36 watts. Even 18 watts seems to be more than plenty for most players.

-g

[KevinOConnor]

I guess it depends on which amp your talking about there Matt and the only guy I know that uses power scaling is KOC and this perticular amp is scaled preamp and all .

Hi Guys!

The above statement is incorrect. I've never produced amps with the preamp Power Scaled.

I experimented with tthat in the late eighties and found I did not like the result. Production amps only ever had the output stage scaled. Some early 2000 model had a tracking switch to also scale the splitter.

The new (2007) Studio amp has individual scaling for each preamp stage in addition to the output stage's control.

TUT4 explains the usual sonic results of Power Scaling some of, more of or the entire amp cricuit. The kits also outline the connection options. Depending on the circuit and the result you want, it can be fine to scale the entire circuit.

Have fun
Kevin O'Connor

[drewl]

To each his own, but it seems like alot of work that none of the bimbos in the audience could tell the difference.

[KevinOConnor]

There's Maven Peal amps that uses their own version of power scaling. The Maven Peal guy and KOC have had some lively debates over the merits of their two systems.

Then there is Mojave amps that has a power scaling system too, might just be a licensed version of one of the two above.

Also, John Suhr is making amps using power scaling. It is a system licensed from London Power.

Hi Guys!

Mojave amps are not Power Scaled. They use a variable current source for the splitter to vary drive to the output stage. As TUT4 points out, the output tube life is NOT extended, and in some cases is worsened using this control. Mesa used the same method on the D-180.

With respect to MP, David and I disagreed on his choices of how he limited his circuit. I also objected to technical statements he made that I assume he knew better than to make - things that could be taken as outright lies. I made my correections and stated that I would no longer respond to anything he posts. I have always recommended his amps and still would had he not closed his business.

There are many builders licensed to use the Power Scale trade names. Implementations can vary and there are new methods used in my own amps and in kits about to be released.

Have fun
Kevin O'Connor