Found a bug! Soldano X99 Clean bright cap

[guitarnerdswe]

I tried this with a bunch of different amps, and only the X99 Clean does this. When the bright cap is active, changing the value of the cap doesn't do anything at all, it sounds the same no matter where you put it.

 

[FractalAudio]

That's because the bright cap on the X99 Clean is not across the Drive pot. The exposed "Bright Cap" is across the Drive pot, the X99 clean channel does not have one. Refer to the X99 (or X88) schematic for more information.

 

[Smilzo]

I vote for adding cap to level pot... it add versatility, and is consistent with axefx amps behaviour.

 

[guitarnerdswe]

That's because the bright cap on the X99 Clean is not across the Drive pot. The exposed "Bright Cap" is across the Drive pot, the X99 clean channel does not have one. Refer to the X99 (or X88) schematic for more information.

But, the other 2 X99 amp modes react to the size of the bright cap? When I change the size of the bright cap on the other 2, the sound changes, the size of the bright cap on the clean X99 clean does nothing.

Just a question, the X88R and the X99 are basically the same preamp besides all the fancy switching right? And the X88R clean has a bright cap (you said the X99 had none at all)?

 

[dk_ace]

I vote for adding cap to level pot... it add versatility, and is consistent with axefx amps behaviour.

I vote we leave it the way it is. The model should be consistent with the way the real amp is designed, not the way other amps are typically designed.

D

 

[dk_ace]

That's because the bright cap on the X99 Clean is not across the Drive pot. The exposed "Bright Cap" is across the Drive pot, the X99 clean channel does not have one. Refer to the X99 (or X88) schematic for more information.

But, the other 2 X99 amp modes react to the size of the bright cap? When I change the size of the bright cap on the other 2, the sound changes, the size of the bright cap on the clean X99 clean does nothing.

Just a question, the X88R and the X99 are basically the same preamp besides all the fancy switching right? And the X88R clean has a bright cap (you said the X99 had none at all)?

The exposed parameter changes the value of the bright cap across the drive pot. The bright cap of the X99 clean channel is not across the drive pot, so you can't change it. The other X99 channels have the bright cap across the drive pot so you can change them.

D

 

[VegaBaby]

I vote we leave it the way it is. The model should be consistent with the way the real amp is designed, not the way other amps are typically designed.

D

+1

 

[guitarnerdswe]

That's because the bright cap on the X99 Clean is not across the Drive pot. The exposed "Bright Cap" is across the Drive pot, the X99 clean channel does not have one. Refer to the X99 (or X88) schematic for more information.

But, the other 2 X99 amp modes react to the size of the bright cap? When I change the size of the bright cap on the other 2, the sound changes, the size of the bright cap on the clean X99 clean does nothing.

Just a question, the X88R and the X99 are basically the same preamp besides all the fancy switching right? And the X88R clean has a bright cap (you said the X99 had none at all)?

The exposed parameter changes the value of the bright cap across the drive pot. The bright cap of the X99 clean channel is not across the drive pot, so you can't change it. The other X99 channels have the bright cap across the drive pot so you can change them.

D

I may be stupid, but I don't get it. I looked at the X88R schematics, and both the crunch and clean channels have 470pf caps on the volume pots. The X99 schematics where a bit confusing, since it shares the same pots for all the channels.

http://www.schematicheaven.com/newamps/soldano_x88r.pdf

Back to the X99 sim:

So when I engage the bright cap, the Axe adds a bright cap across the drive pot, in addition to the one that's not on the drive pot?
Is the one that's NOT on the drive pot, always in circuit?
The bright cap size parameter, which cap is it for?

EDIT: I found another bug regarding this. On the X99 crunch channel, the bright switch changes the sound, even when the drive pot is on 10.

 

[dk_ace]

So when I engage the bright cap, the Axe adds a bright cap across the drive pot, in addition to the one that's not on the drive pot?

Is the one that's NOT on the drive pot, always in circuit?
The bright cap size parameter, which cap is it for?

No. When you engage the bright cap, the Axe adds the bright cap into the circuit where it would be on the real amp. The fact that it's in a different place in the circuit on this amp makes it so that changing the Axe bright cap value parameter does nothing to the sound. The Axe bright cap value parameter is an exposed parameter that will only affect the bright cap value if the cap on the real amp circuit is across the drive pot. I'm sure that's because of Cliff's modeling system and it probably has to be that way.

EDIT: I found another bug regarding this. On the X99 crunch channel, the bright switch changes the sound, even when the drive pot is on 10.

No. You're still confusing bugs with amp design differences.

All amps don't work the same way. That's why they don't all sound the same.

Cliff exposed the bright cap value mainly so that we could change it on amps where we would usually change it on real world amps. The Plexi is a perfect example. That amp is cabable of a lot of different sounds and feels by altering the bright cap and many players have a distinct preference for certain values. I've literally never talked to someone who wanted to play with the bright cap values in their X99. The X99 is a modern amp design with a number of design features that are a departure from vintage amps like the Plexi. Cliff modeled those differences faithfully. You can still play with the bright cap values on most of the modern amps, but they are going to operate differently than the ones on the vintage amps.

Hopefully, that helps you understand it a little better.

D

 

[guitarnerdswe]

So when I engage the bright cap, the Axe adds a bright cap across the drive pot, in addition to the one that's not on the drive pot?

Is the one that's NOT on the drive pot, always in circuit?
The bright cap size parameter, which cap is it for?

No. When you engage the bright cap, the Axe adds the bright cap into the circuit where it would be on the real amp. The fact that it's in a different place in the circuit on this amp makes it so that changing the Axe bright cap value parameter does nothing to the sound. The Axe bright cap value parameter is an exposed parameter that will only affect the bright cap value if the cap on the real amp circuit is across the drive pot. I'm sure that's because of Cliff's modeling system and it probably has to be that way.

EDIT: I found another bug regarding this. On the X99 crunch channel, the bright switch changes the sound, even when the drive pot is on 10.

No. You're still confusing bugs with amp design differences.

All amps don't work the same way. That's why they don't all sound the same.

Cliff exposed the bright cap value mainly so that we could change it on amps where we would usually change it on real world amps. The Plexi is a perfect example. That amp is cabable of a lot of different sounds and feels by altering the bright cap and many players have a distinct preference for certain values. I've literally never talked to someone who wanted to play with the bright cap values in their X99. The X99 is a modern amp design with a number of design features that are a departure from vintage amps like the Plexi. Cliff modeled those differences faithfully. You can still play with the bright cap values on most of the modern amps, but they are going to operate differently than the ones on the vintage amps.

Hopefully, that helps you understand it a little better.

D

I'm pretty sure at least the second thing isn't suppose to be that way.

If the bright cap on the X99 clean is in the circuit, I don't see why it couldn't be affected by the bright cap size parameter, it's still a cap in the circuit, the only difference is that it's effect is static, which it's not if the cap is on the vol pot. Cliff also said the X99 bright cap was at the same place as on the X88R, and the X88R has the bright cap on the volume pot like pretty much all amps out there with switchable brights (see the schematic I posted). So it's two contradicting statements, which confuses me.

Also, you said that the X99 crunch channel bright cap is on the drive pot. In that case, I can't see any technical reason for why it still affects the sound when the drive is at 10. When you have cap on a pot, it's shorted to ground when the pot is fully open, and therefore not affecting the tone. That's why I think it's a bug.

 

[Smilzo]

When you have cap on a pot, it's shorted to ground when the pot is fully open, and therefore not affecting the tone. That's why I think it's a bug.

A bypass cap will bypass the high frequency of the signal, unrelated to pot position. The pot position will change the level of signal with a bit or high end roll off as pot is turned down. The blend of the two is the resulting signal. If you leave otu cap, you loose all bypassed high content.

In my opinion, amp models should be faithful real amp reproduction, with a bit of DIY parameter. Bypass cap is secret "tweaker" juice... :lol:

 

[dk_ace]

Where's the facepalm smilie when you need it.....

Cliff and I have stated the exact same thing like three different ways now and you're still missing the point. I'm out of ways to phrase it.

The bottom line is that this isn't a bug. You can insert and remove the bright cap on the X99 clean model, but you can't change it's value. That is because of it's placement in the real circuit and the way Cliff models amps.

D

 

[guitarnerdswe]

When you have cap on a pot, it's shorted to ground when the pot is fully open, and therefore not affecting the tone. That's why I think it's a bug.

A bypass cap will bypass the high frequency of the signal, unrelated to pot position. The pot position will change the level of signal with a bit or high end roll off as pot is turned down. The blend of the two is the resulting signal. If you leave otu cap, you loose all bypassed high content.

In my opinion, amp models should be faithful real amp reproduction, with a bit of DIY parameter. Bypass cap is secret "tweaker" juice... :lol:

That's not entirerly true. It the same deal as when you have a treble bleed on a guitar pot. At 10 it's shorted to ground, and as you turn down, it bleeds through more to the output. That's why it gets brigther as you turn down the vol pot on the guitar, or the drive knob on an amp with a bright cap. It will not affect the signal when the pot is fully open, unless something is very wrong.

Where's the facepalm smilie when you need it.....

Cliff and I have stated the exact same thing like three different ways now and you're still missing the point. I'm out of ways to phrase it.

The bottom line is that this isn't a bug. You can insert and remove the bright cap on the X99 clean model, but you can't change it's value. That is because of it's placement in the real circuit and the way Cliff models amps.

D

No, the same thing haven't been said 3 times. I've re-read all the post several times, and things just don't add up. You yourself said that the X99 has the cap on the drive pot on the crunch and lead channel, and if that's true, then the bright cap on the crunch isn't working, since it isn't shorting to ground when the pot is at 10.

Even Cliff has said things that don't make sence. He said the X99 clean cap is like that on the X88R, and the X88R bright cap is on the drive pot. It a paradox, it can't be both. Either it's like the X88R and on the drive pot, or it's not and is somewhere else in the signal chain. He also said that the exposed bright cap is on the drive pot, which implies that there is an additional cap on the X99 model, but he must have been talking about the other amp models.

So basically:

If the X99 clean cap is like on the X88R, then it's on the drive pot. If it's not, then it's not like the X88R. Has to be one of them.

If the X99 crunch cap is on the drive pot, it can't/shouldn't affect the sound when the pot is on 10: If it is, the model in the Axe is incorret or has a bug.

 

[Smilzo]

It the same deal as when you have a treble bleed on a guitar pot. At 10 it's shorted to ground

No, never shorted to ground. It shorts the "voltage divider" part between signal and output.

Shorted to ground became a filter, called "tone".

 

[guitarnerdswe]

It the same deal as when you have a treble bleed on a guitar pot. At 10 it's shorted to ground

No, never shorted to ground. It shorts the "voltage divider" part between signal and output.

Shorted to ground became a filter, called "tone".

I can't find the post now, but it was John Suhrs words over at HRI. He basically said "When the pot is on 10, the capacitor is shortened to ground, practically removing it from the circuit".

I know about the voltage divider part and that you mix the signal together with a resistor, I just used the guitar pot as an example. The results are still the same, no change when the pot is fully open, more highs as your turn down. If the cap was on a voltage divider, then it would always be in the circuit, so turning the drive to 10 wouldn't bypass it.

 

[FractalAudio]

It a paradox, it can't be both. Either it's like the X88R and on the drive pot, or it's not and is somewhere else in the signal chain.

Yes it can. Many of the bright circuits have both caps.

The models are correct. Stop worrying about it and enjoy your Axe-Fx.

 

[guitarnerdswe]

That's all I needed to hear!

Just for my curiosity, how simular is the X99 to the X88R?