Welcome, Guest. Please login or register.

October 29, 2020, 08:48:46 PM

Login with username, password and session length

Recent Posts

 

Author Topic: Do Fender, Marshall, Vox, Orange etc. design their cheap ss amps themselves?  (Read 2205 times)

j_flanders

  • Regular
  • **
  • Posts: 10
  • Chip Points: 1
    • View Profile
When you compare the circuit of a Tube Screamer, a Fuzz Face, a Rat and a Big Muff they look like coming from different planets, while if you compare the schematics of those cheap SS amps from the big names (Frontman, Pathfinder, MG, Crush etc.) they look like they came from the same house.

So, I wonder if those companies actually design these little practice amps each themselves or if they are designed by the same 'foreign entity'?

To counter some expected responses:
I do realize that I picked very specific pedals and that a lot of other pedals are very similar to each other.
I do realize that a honky, ratty or fuzzy pedal is for a 'niche target audience' while guitar amps are intended to suit as many players taste as possible.
I do realize there are only so many ways to design an amp, a tone stack, that all of them deal with the same guitar frequencies and all will want to produce as cheaply as possible resulting in a similar choice of values for resistors and caps and other components.
I also realize that both in pedals and amps, people/companies do borrow/steal ideas from each other.

Yet still, the similarities between a lot of those 'cheap mass produced big name ss amps' is striking. And so far, not a single one seems to stand out or do things differently enough to say: hah!.
They all use the same opamps. Fender isn't saying: we'll go with a ne5532 instead of the usual 4558 and our amp will be 1$ more expensive. It's not as if a Fender fan will buy a Marshall MG instead of a Frontman because it's 68$ instead of 69$.
Across those amps they all seem to be using the same few mechanisms for their 'dual channel' switching (see links and examples below)
Another thing that is 'suspect' is that the evolution/iterations of the models of these amp are the same across those brands:
At one time they used transistors, but when they switched to opamps, they all did so.
At one time all of them came with a real analog spring reverb (Frontman 15R, Lead 12R, Pathfinder 15R, crush 15R etc.) and when these (crappy) spring reverbs were left out in a new iteration of these amps, then all brands did so. Not a single one said: we'll keep it.
As far as I can tell they all come with speakers from the same manufacturer (Chunil speakers)

Obviously, they don't build these amps themselves but outsource it to some Far East factory.
So, how does this work? Anyone some inside info on this?
Does a Chinese 'designer' let Fender, Vox, Marshall etc. choose from modules (booster, clipper, tonestack etc)?
Do they get a list with available components and a rough total of components they can use and completely design it in house?
Do they get complete (prototype) designs which they can only fine tune and put their designer's name under it.
Or do they simply order a 'fender sounding' 'Vox sounding' amp and actually don't really care and have little to no input on the circuit design?

Here are some random examples of similarities between schematics where I'm thinking: what a coincidence...

Epiphone Studio 10 vs Vox Pathfinder 15:
http://archive.gibson.com/Files/schematics/Studio%2010.jpg
http://www.tdpri.com/media/vox-pathfinder-15r-schematic.27215/full?d=1349532940
Both using a pot to change feedback resistor of the first non inverting opamp and the input resistor of the second inverting opamp at the same time.
Clipping diodes always in the signal but '(de)activated' by a boost switch (operated through a FET) to '(de)activate' some some parallel resistance in the feedback of the second opamp.

Marshall valvestate 10 vs Vox Pathfinder 10
https://elektrotanya.com/PREVIEWS/63463243/23432455/marshall/marshall_valvestate10_10w_8001_8010.pdf_1.png
http://bencraven.com/wordpress/wp-content/uploads/2016/07/20160528_vox-pathfinder-10-schematic-1024x400.gif
The other way to boost and clip. This time diodes are switched into the signal while at the same time some resistance in the first non-inverting opamp is connected/shunted to ground.

Frontman 15G vs Marshall MG
http://blueguitar.org/new/schem/fender/frontman15g.gif
https://www.electrosmash.com/images/tech/mg10/marshall-mg10-schematic-parts-big.jpg
The third way: bypass the clipping section entirely and as coincidence would have it both use the same type of contour/tone/filter.

I'm not saying all these amps sound the same, far from it, but that a lot of them look like they were designed by the same person.
Maybe I'm looking too much into this or focusing on some peculiar but perfectly explainable similarities but I'd like to hear what people's thoughts on this are.

Are you 'naive' and wishful thinking like me and secretly hoping that even that Pathfinder you love so much was designed by someone at Vox that had Vox tones running through his veins and gave everything he got to capture the legendary signature sound of his company/brand in this little cheap ss amp?
Or do you think it breaths as much Vox as a Joyo ACtone: Chinese crap that happens to sound good but nothing to get emotionally attached to.

Also, why is there no Mesa 15G ? They seem to be the only 'big name' in this that does not take part in the 'cheap ss practice amp' field.

And as a last note: why do all of them, as far as I've seen, clip to ground (or the inverting pin which boils down to the same thing) and none seem to do the 'non-inverting feedback clipping'.
Clipping to ground, especially with higher supply voltages than the pedalwise 9V, does provide for a little more dynamics but at the same time especially with those small cheap speakers it gives fizzy, crackly note decay at edge of break up settings and 'bees in a can' for higher gain settings. This is what people associate ss pratice amps with and with feedback clipping you'd have none of that.






Katoda

  • Regular
  • **
  • Posts: 45
  • Chip Points: 4
    • View Profile
Cheap practice amps are just that - cheap practice amps. The design goal is the same in all of them - lowest cost possible. That's why there are op amps with clipping diodes, fets are more expensive.
At least that's what I think...

Enzo

  • Legendary
  • ******
  • Posts: 1979
  • Chip Points: 214
    • View Profile
I am pretty sure they design their own, because it is something any engineer can do on a napkin in  bar.  They do not need help for these most basic things.  They all look the same because they all do the same job.

WHy did they all use 4558 instead of something else?  Well they already used 4558 for most everything and bought them by the million.  Nerdy basement techs like us get all squishy "upgrading" to a 5532 or something, but the plain vanilla 4558 works just fine, so why go to extra expense?

Typical little Frontman or Crate GX15 needs a basic power amp - TDA2050 - and a couple stages of op amp gain - 4558.  Diodes for clipping?  Sure.  Tone controls?  Check.

Sure there might be times when some offshore place has something ready to fly, and they snatch it up.  But do to the simplicity of these things, they are just as likely to say to their offshore plant team, "throw us together a basic practice amp."  And so you get some odd drawing signed by Wing Wang.


Something else to consider is that these products are aimed at a market niche.  And all the competing basic models compete for those same niches.  Mesa doesn't sell bottom end amps.  They don't market to that niche.  Whether you like them or not, Mesa markets as a higher end brand.  An Acura rather than a Honda, so to speak.

Maybe burgers is a better simile.  You have fast food burgers, which include a dollar menu choice.  Then there are fancy burger places like Red Robin or even Dennys or your local bar.  None of those places offers a dollar menu.

But look at those dollar burgers.  All have a same size hunk of cheap beef, all have mustard and ketchup squirted on, all have a square of sliced cheese.  And all come with a little bag of small cut fries with loads of salt.

Clipping across the signal path or across the gain stage isn't all that different to me.  Your pair of penny diodes is in either.

j_flanders

  • Regular
  • **
  • Posts: 10
  • Chip Points: 1
    • View Profile
Thanks for the replies!

I am pretty sure they design their own, because it is something any engineer can do on a napkin in  bar.  They do not need help for these most basic things.  They all look the same because they all do the same job. Sure there might be times when some offshore place has something ready to fly, and they snatch it up.  But do to the simplicity of these things, they are just as likely to say to their offshore plant team, "throw us together a basic practice amp."  And so you get some odd drawing signed by Wing Wang.
OK, I wasn't implying that they need help. Quite the opposite, that they maybe simply wouldn't bother.
I didn't even consider the possibility that all those companies (Marshall, Fender, Vox, Orange, Kustom, Artec, Laney, Danelectro, Randall etc etc. ) had their own plant for producing these ss amps.
It's probably my wrong assumption but I thought all these amps came from the same (couple of) factories. Kinda like a Cort or Samick factory but for ss amps. Given that idea and the peculiar similarities I wondered if they would perhaps not even bother designing these circuits themselves. Hence the topic.

Something else to consider is that these products are aimed at a market niche.  And all the competing basic models compete for those same niches.  Mesa doesn't sell bottom end amps.  They don't market to that niche.  Whether you like them or not, Mesa markets as a higher end brand.  An Acura rather than a Honda, so to speak.

Maybe burgers is a better simile.  You have fast food burgers, which include a dollar menu choice.  Then there are fancy burger places like Red Robin or even Dennys or your local bar.  None of those places offers a dollar menu.

But look at those dollar burgers.  All have a same size hunk of cheap beef, all have mustard and ketchup squirted on, all have a square of sliced cheese.  And all come with a little bag of small cut fries with loads of salt.
Yeah, I understand but still, I always thought Mesa is the odd one out.
Ask some non guitar playing but guitar music loving guys to name some amps and the list would probably be:
Marshall, Fender, Vox, Orange and Mesa. That would include Mesa in the list of the big 5 (don't know about Ampeg)
None would say Friedman, Ceriatone, Dr Z or so, since you're talking higher end.
And, while 1 dollar meal places might not serve a 25$ wagyu beef burger, and Red Robin doesn't sell a 1$ burger, Marshall and Orange do in fact have amps in the same upper price range as Mesa. But you made a point about it being/wanting to be high end only.

Clipping across the signal path or across the gain stage isn't all that different to me.  Your pair of penny diodes is in either.
If you apply insane amounts of gain you'll end up with a square wave which sounds the same no matter what clipping circuit created it.
But at lower levels of clipping however, I thought there was a fundamental difference between:
- diodes in the feedback loop of a non-inverting opamp
and
- clipping to ground or in the feedback loop of an inverting opamp

Inverting feedback or to ground:


Non inverting feedback:


To my ears, having part of the original mixed in (diodes in non inverting feedback) sounds very different from simply having the tops clipped or rounded.
« Last Edit: January 30, 2018, 08:56:04 PM by j_flanders »

Enzo

  • Legendary
  • ******
  • Posts: 1979
  • Chip Points: 214
    • View Profile
COnsider some guy slapping one of these together.  he doesn't have to do any analysis, he can just stick a pair of diodes in there somewhere.  If they sound a little different, so be it.  They can use LEDs instead of 1N4148s for a little difference, but the circuit is the same.

Fender, et al, don't use Chinese factories just for the basic practice amps, they make a large chunk of stuff there.  The amps you bring up are basic, but look at the Fender FM212R.  it is a very complex circuit, yet still on the Chinese menu, and still on the replace rather than repair warranty list because they are so cheap to make.


And when I said need help, I didn't mean top imply they were not up to the task, I just meant that farming the design out didn;t really save them anything since any engineer could bang out this design in an afternoon.

If they all came from the same factory, they would all have the same circuit board, or one almost the same.  But look inside the Crate GX15 and the Fender FM15 and they are not the same.


I am of the opinion that Fender can't design a dirt channel to save their souls.  And in the case of a small FM series amp, no one sat down at the drawing board looking for amazing nuance and some percent or other of even order versus odd order harmonics.  They said to them selves, lets stick in some clipping diode to razz out the dirt channel.  That you find some detectable difference between two ways to stuff clippers in there is all well and good, but I think not the designer's goal.

Put your scope traces on the same sweep rate, and they look more similar, at least to me.