poweramp-driven "liquid" distortion.

[katopan]

In my opinion that singing sound comes from heavily overdriven power pentodes in push-pull (too many p's!) with an OT impedance that at least puts the load line just below the knee if not a fair bit below it. Lots of yummy screen compression! But I'm no help because I can't recommend an off the shelf amp and not many of them have what I've decribed above. Commercial you're probably stuck with EL84s or EL34s for 15, 30, 50 or 100W.

DIY widens out the options from about 4W up to 100W.

If you're playing at home you don't need all that power. Very few pedals do what you're after, but schottky diode clipping is much softer and doesn't have the crunch of other clippers. The Zendrive is based around them and will sing for sure. A couple in series can get a very soft distortion with no crunch that will sustain for ages. DIY alternative to that is the Wattkins RF Drive PCB. Then you could use any small clean amp like a Blues Junior or something.

[Zippy]

The Zendrive will sing, and a couple in series can get a very soft distortion with no crunch that will sustain for ages.

+1 on the Zendrive. I use one with my 5F4 tweed Super.

[Edoardo]

How do you know that power amp distortion is what you are after? Do you like the tone of the Bludo? That is not power amp distortion.

I had never heard about Bludo amps, I had to google.

I realized that power amp distortion is what I'm after after having heard some cranked up amps (gain set low, volume set to 10), few live and many via youtube demo/tutorials, and after having lurked in 5 or 6 different gear forums, and after having read 3 or 4 articles speaking about how an amp is made, how to choose a tube amp etc.

[Edoardo]

In my opinion that singing sound comes from heavily overdriven power pentodes in push-pull (too many p's!) with an OT impedance that at least puts the load line just below the knee if not a fair bit below it.

Thanks. But what does "to put the load line below the knee" mean? (Below what?) I don't get whether the OT would have to be "bigger"-than-average or what.

Lots of yummy screen compression!

Yeah!

And the only way to achieve the compression, else, "to put the load line below the knee", is using a Pentode AND Push-Pull Power Amp?

But I'm no help because I can't recommend an off the shelf amp and not many of them have what I've decribed above. Commercial you're probably stuck with EL84s or EL34s for 15, 30, 50 or 100W.

I've noticed too many EL84, but some 6V6 and EL34s... But... EL34s are pentodes, no?
Is it true, however, that I the EL84s are much crunchier than the 6v6 and that I shall avoid them?

schottky diode clipping is much softer and doesn't have the crunch of other clippers.

so clipping diodes featured = better for me?

The Zendrive will sing, and a couple in series can get a very soft distortion with no crunch that will sustain for ages.

Thanks a lot for this tip!

[Edoardo]

the OTS Lunchbox is perfect for what you want, already built and under $700.

Thanks a lot man. This little one is tempting!





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I see they "kindly" suggest to buy their active external buffer/effects loop for exploiting the passive amp effects loop.

Do their buffer/loops have something special or can I get another buffer?

Their "Klein-ulator" SS loop isn't expensive though...


How does this amp behave with effects put before the instrument input?

[Edoardo]

Look at used brown note, they also have a 22 watt version if u are concerned with volume

Thanks, but these ones may be too hard to find used in Europe

[Reeltarded]

In my opinion that singing sound comes from heavily overdriven power pentodes in push-pull (too many p's!) with an OT impedance that at least puts the load line just below the knee if not a fair bit below it.

Higher primary impedances like a 100w Marshall at 2.2-2.5k instead of 1.7k. No help, I know...

You confuse me. You describe this searing smooth distortion sound, say that Eric Johnson sounds modern, then say John Lee Hooker which isn't searing or sustaining in any kind of way. Is that even distorted? (haha BillyZ don't hit me)

I think you could be happy with almost any combo amp and a Xpandora type pedal compressor but never use the compressor.

[katopan]

Thanks. But what does "to put the load line below the knee" mean? (Below what?) I don't get whether the OT would have to be "bigger"-than-average or what.

Sorry, I've spouted out with too much information. Load line position relative to the valve response curves, a design step which leads to choosing the OT primary reflected impedance - something which has a huge impact on tone.

Yeah!

And the only way to achieve the compression, else, "to put the load line below the knee", is using a Pentode AND Push-Pull Power Amp?

Pentodes (EL84, EL34) draw more screen current than tetrodes (6V6, 6L6) and even more is drawn with a higher OT impedance. More screen current through screen resistors creates more screen compression before clipping, which creates smoother distortion. In push-pull you can get this smoothness on both sides of the waveform. Single ended can't do it.

I've noticed too many EL84, but some 6V6 and EL34s... But... EL34s are pentodes, no?
Is it true, however, that I the EL84s are much crunchier than the 6v6 and that I shall avoid them?

EL34s are pentodes. EL84s are only crunchy if the amp has been designed to sound that way because of PI and preamp distortion or tone shaping. Unfortunately the big names think that's what people want out of a 15-18W amp, and you get results like the Tiny Terror which I'd call anything but smooth. But when you see a schematic it is designed that way.

so clipping diodes featured = better for me?

Only schottky diodes are that soft (and lower value zeners). Silicon clipping diodes or LEDs are crunchy. So no, the standard diode clipping will not do what you are after. I only mention the Zendrive because it is unique in the way it stacks schottky diodes on top of silicon diode clipping(actually a mosfet in the Zendrive) to smooth things out substantially and makes the pedal really sing compared to the standard assortment of diode clippers. The RF Drive is a DIY circuit that achieves the same thing.

[Edoardo]

In my opinion that singing sound comes from heavily overdriven power pentodes in push-pull (too many p's!) with an OT impedance that at least puts the load line just below the knee if not a fair bit below it.

Higher primary impedances like a 100w Marshall at 2.2-2.5k instead of 1.7k. No help, I know...

You confuse me. You describe this searing smooth distortion sound, say that Eric Johnson sounds modern, then say John Lee Hooker which isn't searing or sustaining in any kind of way. Is that even distorted? (haha BillyZ don't hit me)

I think you could be happy with almost any combo amp and a Xpandora type pedal compressor but never use the compressor.

Correct me... you mean a big OT increases the impedance out of the amp of a 50% and this makes the speaker suffer under a higher load.


Yes Eric Johnson's "colour" is too guitarheroish to me.
John Lee Hooker is not the kind of guitarist that lines up 2 compressors for a 10-minute solo, it's just that when he picks the strings a little harder on some recordings, the amp seem overdrive the way I mean.

[Edoardo]

Yeah!

And the only way to achieve the compression, else, "to put the load line below the knee", is using a Pentode AND Push-Pull Power Amp?

Pentodes (EL84, EL34) draw more screen current than tetrodes (6V6, 6L6) and even more is drawn with a higher OT impedance. More screen current through screen resistors creates more screen compression before clipping, which creates smoother distortion. In push-pull you can get this smoothness on both sides of the waveform. Single ended can't do it.

thanks... could you please take a look at this circuit... is this one a push pull?

http://www.ceriatone.com/images/layoutP ... nchbox.jpg

And... Can I change the 6v6 to a EL34 with some easy/cheap wiring mods?

I've noticed too many EL84, but some 6V6 and EL34s... But... EL34s are pentodes, no?
Is it true, however, that I the EL84s are much crunchier than the 6v6 and that I shall avoid them?

EL34s are pentodes. EL84s are only crunchy if the amp has been designed to sound that way because of PI and preamp distortion or tone shaping. Unfortunately the big names think that's what people want out of a 15-18W amp, and you get results like the Tiny Terror which I'd call anything but smooth. But when you see a schematic it is designed that way.

so clipping diodes featured = better for me?

Only schottky diodes are that soft (and lower value zeners). Silicon clipping diodes or LEDs are crunchy. So no, the standard diode clipping will not do what you are after. I only mention the Zendrive because it is unique in the way it stacks schottky diodes on top of silicon diode clipping(actually a mosfet in the Zendrive) to smooth things out substantially and makes the pedal really sing compared to the standard assortment of diode clippers. The RF Drive is a DIY circuit that achieves the same thing.

Thanks. That's a lot of great stuff. Lots of things to study.

I'm glad I've asked here!

[Reeltarded]

I think you are looking for a Super Reverb. Seriously!

[billyz]

I would not hit anyone . I get creamy tones with good humbuckers and 6v6's.

[M Fowler]

I think you are looking for a Super Reverb. Seriously!

I could sell you my custom built for me, thanks Henry, Redplate Amps Blackverb combo. It can do what you want. It has two loops, effects loop and Dumble distortion loop. Has a 5 position selector to give me different variations of Fender tones, Super, Twin, etc.

But the price slightly over your budget $2200.

Mark

[Edoardo]

I think you are looking for a Super Reverb. Seriously!

Thanks a lot! If I found one used I'd consider this one also...!
But I must ask... did you come to this because of the Johnson/Hooker "explanation" or because of all the rest??



By the It's not just the price, the Super Reverb is a HUGE piece of gear...
...doesn't a 1x12" or head clone exist?
Some (smaller) Ceriatone or Frenzel maybe?



Anyway, why the Super Reverb? Yes it does what I want, but how/why?

Thanks

[Randall]

John Lee Hooker probably couldn't have cared less what cheap low power amp he used, and I'd wager he never used a pedal. His tone comes from his hands.