please define "great tube sound"..help!

[tranceracer]

Hey DSchwartz, this is a great thread thanks for brining it up!

IMHO, there are many great solid state effects (many on this forum) and digital amp simulators.  Since I don't gig and mostly record in my small home studio, my environment is not accommodating to huge amps so for me Digital simulators into a solid state amp (Mackie HR824) is my rig of choice.  I don't own any tube effects but may build the Matsumi pre.  Of course nothing beats a stack cranked to "12" but a good digital amp simulators seem to work for lower volume level environment and do a relatively good job emulating the "feel" or "simulate" that cranked stack, power tube distortion tone. 

"what do i want to achieve? what sounds good? good for what? "
Are great questions in the quest for that perfect tone. 

I am by far no expert but my layman's understanding of solid state and tube tonal characteristics is that as the saturation point of a solid state device is exceeded, the distortion characteristics become more non musical and distortion increases exponentially which means that the musical "sweet spot" for solid state distortion is finite.  A perfect example I've found with my amp sims and digital effects is when I overdrive the sims into digital distortion, you can really hear a harsh, annoying clipping.  So I have to constantly watch the input levels (it's kind of a pain actually).

Whereas, tube distortion is linear, which theoretically results in a much wider and dynamic sweet spot before it goes into over saturation.  You can feed a tube pre or amp almost infinite amount of gain and the distortion will increase linearly no harsh digital or SS type clipping.

A simple example is a Tube vs. solid state power amp.  Tube power amps can drive itself to distortion and still sound musical and maintain the harmonic subtleties and nuances.  Which is why many people, including myself, think a tube power amp distortion seems to sounds better and have more dynamics than a loud solid state amp sim live.  On the other hand, if a solid state power amp is pushed into distortion there will definitely result in some non musical "tones".  That harsh non musical (speaker damaging) clipping is the exponential distortion theory in action. 

So back to the question:
what do i want to achieve? what sounds good? good for what?

I guess that's why we're all here on this forum, in our never ending quest to find that perfect tone in the pot of pedals at the end of the Rainbow! 

-tR

[Gus]

Lets look at it another way hybrid amps

tube and maybe some solid state preamp to a solid state no output transformer speaker not part of the power amp feedback loop or part of the power amp feedback loop

All solid state to a tube output with a transformer like some older musicman amps

Whats going on when you are driving the output pentodes or beam power tubes into an output transformer?  Whats the screen voltage compared to the plate voltage etc........

[hellwood]

OK, way too much technical mumbo-jumbo. save up some cash, get a real tube amp that blows your mind and never look back!

[soulsonic]

I think having a transformer somewhere in the circuit adds something important. I'm thinking about the Sunn Concert series which use a coupling transformer between driver and output amp for phase splitting. Very nice sounding amps.
High-voltage MOSFETs with a tube amp output transformer? That's something worth considering.

[dschwartz]

OK, way too much technical mumbo-jumbo. save up some cash, get a real tube amp that blows your mind and never look back!

that´ps not the discussion here.. tube v/s SS has been widely discussed and studied..just buying a tube amp would be the easy way out..not the creative, interesting one...

I think having a transformer somewhere in the circuit adds something important. I'm thinking about the Sunn Concert series which use a coupling transformer between driver and output amp for phase splitting. Very nice sounding amps.
High-voltage MOSFETs with a tube amp output transformer? That's something worth considering.

i allways think about that...even thought about putting a small audio transformer at the output of a dr boogie..but as always, i just keep the idea and never actually do it..in fact i always wonder why no one in this forum never tried it (or tried it and kept in secret ?? :S)

[Jered]

One man's ceiling is another man's floor.

One man's fish is another man's poisson.

  Indeed! I think that's what I was trying to say. Well put RG.
  Jered

[hellwood]

OK, way too much technical mumbo-jumbo. save up some cash, get a real tube amp that blows your mind and never look back!

that´ps not the discussion here.. tube v/s SS has been widely discussed and studied..just buying a tube amp would be the easy way out..not the creative, interesting one...

OK, im sorry, you are right, but if you get a good tube amp while you are figuring this all out, you will have saved yourself a lot of time!

[nordine]

i allways think about that...even thought about putting a small audio transformer at the output of a dr boogie..but as always, i just keep the idea and never actually do it..in fact i always wonder why no one in this forum never tried it (or tried it and kept in secret ?? :S)

i think there's an emulation called the Firezog (of a Herzog, of course),  ... has a transformer trick i believe, it never past the 'schematic' state, AFAIK

[R.G.]

I think having a transformer somewhere in the circuit adds something important. I'm thinking about the Sunn Concert series which use a coupling transformer between driver and output amp for phase splitting. Very nice sounding amps.
High-voltage MOSFETs with a tube amp output transformer? That's something worth considering.

i allways think about that...even thought about putting a small audio transformer at the output of a dr boogie..but as always, i just keep the idea and never actually do it..in fact i always wonder why no one in this forum never tried it (or tried it and kept in secret ?? :S)

(a) I'm always thumping the tub for solid state Vox amps which use the driver transformer - and that mysterious adjustable limiter ahead of the power amp
(b) MOSFETs plus transformer have been tried, I assure you.    There are several reasons for keeping something a secret, among them that (1) it's too good to share, (2) it's of no worth whatsoever and therefore not worth mentioning or (3) it's so bad that you don't want anyone to know you did it.

[R.G.]

I should probably add to this. I built the best sounding tube amp I've ever used - that is, it fit MY personal preferences in sound better than any other amp I've tried.

It had three tubes in it - two 12AX7's and a 6AQ5. The power was probably 3W. The transformers came out of a Magnavox home "hifi console", the 50s/60s furniture things with a record changer, am/fm, and record storage as well as speakers. The 12AX7s were arranged in a normal/overdrive setup and harshly low passed on their inputs with 100K grid stoppers. The single ended output saturated easily, softly, and asymmetrically.  Other than that, the circuits were right out of the RCA manual.

So go find yourself a Magnavox console that's about 50 years old...   

[raulgrell]

There are several reasons for keeping something a secret, among them that (1) it's too good to share, (2) it's of no worth whatsoever and therefore not worth mentioning or (3) it's so bad that you don't want anyone to know you did it.

I assure you it's the first. I experimented with several applications for transformers in distortion circuits and came up with a very interesting way of getting the mid-range warmth and lower fequency punch with SS circuits. It isn't exactly a tube sound, but it sounds good and it's SS... Couldn't ask for more.

I'm exploring the possibility of selling my design to local boutiquers. If that doesn't work out, I'll share the schematic...

[Gus]

High power mosfets and a transformer out.  PRS solid state amps

   R.G, posted that limiter circuit fragment years ago as a mystery circuit IIRC  very clever design. 

Using transformers with solid state is old news.  The  Pignose amp is one example IIRC.