Virtual guitar amps/analog guitar amps

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Maybe Common Sense is one of those clever names they give weed in Colorado and it's not very good.

Dude, all I got is some Common Sense ragweed, got to score me some Bubba Kush!
 
There are two sides of the coin here. I have owned two recording studios, (full multi room professional) and I have been fortunate to perform live in many venues from Texas to California. There is a place for the newer digital stuff, but the analog amps are still the choice of any musician I have talked with in the last ten years until now. I own both types of equipment and in the studio I have had groups which are into the most modern technology still using their tube amps in the studio as well as live. As for myself, I use both in the studio, but for live applications I always use my analog amps, sometimes combined with my favorite pedal. The fact is that I just built a vacuum tube amp completely from scratch and I cant find anything digital which will give me that same breakup when that tube rectifier reaches the "sag" point. There are places for both types of equipment, but don't discount the analog tube stuff as I have found it to be the choice of not only the people from my generation, but those who are just now emerging.
Texasound'
ASP, Associated Sound Productions
 
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Texasound said:
...I cant find anything digital which will give me that same breakup when that tube rectifier reaches the "sag" point.
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Nothing behaves like a tube rectified amp....and different types of rectifiers will completely change the character of an amp.
If there's any one tube to swap for an obvious change, it would be the rectifier, assuming the amp design allows for different rectifier types.
I've got a few that will take any one of 2-4 rectifiers, and I'll swap them out occasionally just for that reason.
You can't get that with simulations, which tend to be more "mathematical" in how they provide tone/feel.


Texasound said:
There are places for both types of equipment, but don't discount the analog tube stuff as I have found it to be the choice of not only the people from my generation, but those who are just now emerging.
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Right....it's a wonderful, hybrid audio world these days, and we can make the most of it with selective application.
 
miroslav said:
You can't get that with simulations, which tend to be more "mathematical" in how they provide tone/feel.
.
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You know which side I'm on here, but I gotta correct you on this. Some of the nicer sim applications do have provisions for tweaking sag. Is it as good as the real thing? Hell no, but they try.
 
Greg_L said:
You know which side I'm on here, but I gotta correct you on this. Some of the nicer sim applications do have provisions for tweaking sag. Is it as good as the real thing? Hell no, but they try.
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Oh yeah, I know they do, and I didn't mean to suggest they ain't trying...:D....but as I said, it's done as a "mathematical" process, and real tube rectifiers just don't work that way. There's a more "organic" nature to real tubes, a certain amount of randomness, unlike the homogenized math.

Last weekend I spent most of a day messing with one amp (that's when I got zapped a couple of times, like I mentioned in the Guitar Forum)...and I was trying out different tubes, to include different rectifiers and solid-state subs.
The amp can take 5Y3, 5U4GB, 5AR4/GZ34 rectifiers...and with all the pre/power tubes constant, it was amazing how much effect the rectifiers had on the amp's tone/headroom/feel.
For the amp in question (a modified 5E3 circuit that has more power and bigger trannys), I went with the 5U4GB. The 5Y3 proved to be mushy, though at some volume/tone settings, and lower gain input, it was sweet. The GZ34 kicked it up a lot, and opened the headroom quite a bit, and I can see sometimes using that...but for now it's the 5U4GB.
On some other amps where I can sub the rectifier....I'm using 5Y3 or the 5AR4/GZ34....it's a a matter of just trying a bunch of tubes and finding the combination you like most.
 
miroslav said:
Oh yeah, I know they do, and I didn't mean to suggest they ain't trying...:D....but as I said, it's done as a "mathematical" process, and real tube rectifiers just don't work that way. There's a more "organic" nature to real tubes, a certain amount of randomness, unlike the homogenized math.

Last weekend I spent most of a day messing with one amp (that's when I got zapped a couple of times, like I mentioned in the Guitar Forum)...and I was trying out different tubes, to include different rectifiers and solid-state subs.
The amp can take 5Y3, 5U4GB, 5AR4/GZ34 rectifiers...and with all the pre/power tubes constant, it was amazing how much effect the rectifiers had on the amp's tone/headroom/feel.
For the amp in question (a modified 5E3 circuit that has more power and bigger trannys), I went with the 5U4GB. The 5Y3 proved to be mushy, though at some volume/tone settings, and lower gain input, it was sweet. The GZ34 kicked it up a lot, and opened the headroom quite a bit, and I can see sometimes using that...but for now it's the 5U4GB.
On some other amps where I can sub the rectifier....I'm using 5Y3 or the 5AR4/GZ34....it's a a matter of just trying a bunch of tubes and finding the combination you like most.
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The ID series can do this because it models COMPONENTS not amps. In any case, many folks say a solid state rect and a series R is hard to tell from a thermionic rectifier.

But I have to agree with the sentiment that whatever works for YOU in any particular situation is "right".

Dave.
 
ecc83 said:
The ID series can do this because it models COMPONENTS not amps.
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Not sure what you are referring to..."ID series"...?

ecc83 said:
In any case, many folks say a solid state rect and a series R is hard to tell from a thermionic rectifier.

But I have to agree with the sentiment that whatever works for YOU in any particular situation is "right".
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Well...I've swapped SS and tube rectifiers in the same amp and the SS work fine, no real complaints.
Do they sound/feel identical....?...mmmm about the same way one tube compares to another. :)

I think you have to be really "married" to an amp for awhile before you start to notice the very subtle pros/cons/differences when trying out tubes or when playing it....sorta just like a woman.
Not sure how many people really get into the subtleties instead of just going with the superficial impressions of either. ;)

I have two amps with SS rect and five with tube rect (or I can do an SS sub)....and I like them all.
 
How does the rectifier affect the sound of an amp?

and

What is "sag"
 
PDP said:
How does the rectifier affect the sound of an amp?

and

What is "sag"
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The rectifier is part of the power supply that converts the AC from the wall to what the rest of the circuit needs to operate. Rectifiers specifically change AC to "lumpy" DC which is then smoothed by the filter capacitors. When the power draw of the circuit is strong enough a tube rectifier can fall behind a little and so the voltage (I think) drops below the norm, and that affects the sound of the amp. It has become part of the tube amp sound that many players expect and exploit.
 
bouldersoundguy said:
The rectifier is part of the power supply that converts the AC from the wall to what the rest of the circuit needs to operate. Rectifiers specifically change AC to "lumpy" DC which is then smoothed by the filter capacitors. When the power draw of the circuit is strong enough a tube rectifier can fall behind a little and so the voltage (I think) drops below the norm, and that affects the sound of the amp. It has become part of the tube amp sound that many players expect and exploit.
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Thanks, that's interesting. I' ve read rumors that some guitar players have used variacs to get a dirty tone from their tube amp. Never tried it, nor seen anyone actually do it.

Another interesting thing I read was that old amps were meant to run on 110, but todays voltages can run up as high as 125, so if your running vintage gear its actually a good idea to run off a variac to avoid blowing up your amp.
 
I use sims (NI guitar rig, Line 6, Amplitube, etc) and I think they're alright, but I guess I still like to move real air around (like a dinosaur farting). Here's a question. I know you can iso the guitar sound through monitors with a sim running, and play along to a separate headphone mix, and this is how I have achieved all-important FEEDBACK with sims in the past, BUT is there a way that sims can model feedback without the guitar signal hitting the air? I'm not sure how - it seems like an organic process that depends on the guitar, pick-ups, room, gain, proximity blah blah blah. Without feedback, to me, it ain't rock and roll...
(Sorry if this has already been covered - this thread is already 51 pages long and I just can't invest the time to read it all at present)
 
bouldersoundguy said:
The rectifier is part of the power supply that converts the AC from the wall to what the rest of the circuit needs to operate. Rectifiers specifically change AC to "lumpy" DC which is then smoothed by the filter capacitors. When the power draw of the circuit is strong enough a tube rectifier can fall behind a little and so the voltage (I think) drops below the norm, and that affects the sound of the amp. It has become part of the tube amp sound that many players expect and exploit.
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Close enough BSG. The rectifier has an internal resistance (as do all electronic devices) and thus there is a voltage drop or "sag" as more current is pulled as per our old friend Mr Ohm.
The internal resistance of sstsate rectifiers is only an Ohm or so whereas valve rects are 50, 60 or even more Ohms. Ok, valves are not PERFECTLY "ohmic" but putting in some series resistance mimics the valve very closely indeed according to amp gurus such as Merlin Blencowe.

Yes Greg, worked, been gone since September but I have no wish to even appear to spam!

And "living with an amp"? Forgive me if I am a bit sus' here? A valve amp will never be perfectly stable. The biggest change will be mains voltage variations causing not only headroom shifts but also bias variations (in fixed biased amps). Bias will shift with "programme history" i.e. after a big, full power blast the bias will be off by 5 or 10% for quite some seconds. Then as the amp heats up over some hours, transformer winding resistances will increase. Yes, all these variations WILL be minor and "subtle" but likely to mask I would think other subtleties? What I am saying is, you are never, quite, playing the SAME amp day to day!

Dave.
 
"Well...I've swapped SS and tube rectifiers in the same amp and the SS work fine, no real complaints.
Do they sound/feel identical....?...mmmm about the same way one tube compares to another"

Can I inject a word of caution here and point out a flaw in the MO? Amps that use silicon rects TEND to have big value filter caps. 220mfd as the first cap is not unusual but 100mfd is very common. Valve rectifiers impose a limit on the size of reservoir cap and 60mfd is about as big as it can get and 47mfd is safer. So, if you gaily go bolting in a valve rect in place of sstate you could be blowing GZ34*s for ever more! I do understand however that peeps are more likely to shunt a valve with diodes than the other way around.

The flaw in the MO is that sstate rectified amps TEND to have bigger caps than valved jobbies and these will counter sag to some extent. Many old valve amps had only 8mfd smoothing capacitors!

*Not all rect valves have the same max cap value so check this before you swap things about. Valves ain't cheap!

Forgot! (only one coffee so far) Fitting silicon diodes will cause the HT to rise above that due to a valve so slap a meter on the +B rail as a blown filter cap makes a hell of a bloody mess. Always best to bring up "experimentals" on a Variac.

Dave.
 
MrWrenchey said:
Amen, brother.

I'm sure Greg will agree with you as well. xD
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Greg agrees. I love a chord or note sustaining into feedback. That's part of why I like tracking next to my big loud amps.


As far as tube vs SS rectifiers in a tube amp, I think I prefer SS. I don't have much experience with testing one against the other, but I do know that I tend to like the bite and attack or SS rectifiers over the "sag" of tube.
 
Greg_L said:
Greg agrees. I love a chord or note sustaining into feedback. That's part of why I like tracking next to my big loud amps.


As far as tube vs SS rectifiers in a tube amp, I think I prefer SS. I don't have much experience with testing one against the other, but I do know that I tend to like the bite and attack or SS rectifiers over the "sag" of tube.
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Well! You DO surprise me Greg! I would have put you down as one who was all dewey eyed about saggy thermionics!

As a technician I LOVE solid state rects. Hardly ever fail and if they do it is because some penny-pinching bean counter has insisted on a cheap, close rated device.

Dave.
 
ecc83 said:
Well! You DO surprise me Greg! I would have put you down as one who was all dewey eyed about saggy thermionics!

As a technician I LOVE solid state rects. Hardly ever fail and if they do it is because some penny-pinching bean counter has insisted on a cheap, close rated device.

Dave.
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Lol. No not really. My style is usually fast and aggressive. I want immediate reaction. Really though I'm not good enough for it to matter either way. I just prefer the sound and feel of SS rectumfryers.
 
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