why DIODE CLIPPING in AMP ?

[Ventura]

It is a valid question.

That said, master amp designers can and have created some of the finest toanz we know of by strategically placing diodes in the circuit to attain a special kinda something.

Is it worth the price (?) - this is the contemplation. No right or wrong answer. Dumble used Radio Shack parts and his amps ain't cheap (could be supply and demand, hard to gauge). Friedman is employing diodes; his amps aren't cheap and they're readily available - so are we buying his expertise in amazing tone producing amps or overpaying for solid-state short-cuts? The answer's in the ears of the player.

Excellent topic though. Thought provoking and one I've brought up many a time amongst fellow musos.

 

[kdmay]

It’s a good question.

No one really knows what’s going on inside the Fortin Cali. He claims Violence mode engages a 4th gain stage, but there are only 3 12AX7s, so with a Cathode Follower, that only leaves 3 gain stages. And typically the Jose circuits (which I am presuming is the Cali reference) have Cathode Followers.

Now he could be using a plate fed tone stack and deriving the 4th stage that way, very possible. But it would be a completely different beast. Having said that, IIRC the Fortin Bones was plate fed, so it’s very possible. In which case, it would differ quite a bit from the Helios, Atomica and Friedman Small Box.

Incidentally, the new Helios Eclipse claims 6 gain stages for the Ecplise+ mode. I’ve always thought this was just diode clipping, but I could be wrong. The Wizard MTL has 6 gain stages, but with diode clipping and a feedback driven recovery stage (unique to this amp and the Jubillee), it’s another beast again!

That is exceptional. Thank you very much.

I was trying to discern how different or similar the Fortin Cali would sound from the Helios 50 or Friedman built Atomica.

 

[IntenseJim]

It’s a good question.

No one really knows what’s going on inside the Fortin Cali. He claims Violence mode engages a 4th gain stage, but there are only 3 12AX7s, so with a Cathode Follower, that only leaves 3 gain stages. And typically the Jose circuits (which I am presuming is the Cali reference) have Cathode Followers.

Now he could be using a plate fed tone stack and deriving the 4th stage that way, very possible. But it would be a completely different beast. Having said that, IIRC the Fortin Bones was plate fed, so it’s very possible. In which case, it would differ quite a bit from the Helios, Atomica and Friedman Small Box.

Incidentally, the new Helios Eclipse claims 6 gain stages for the Ecplise+ mode. I’ve always thought this was just diode clipping, but I could be wrong. The Wizard MTL has 6 gain stages, but with diode clipping and a feedback driven recovery stage (unique to this amp and the Jubillee), it’s another beast again!

That is exceptional. Thank you very much.

I was trying to discern how different or similar the Fortin Cali would sound from the Helios 50 or Friedman built Atomica.

You guys are an incredible resource.
I was reviewing this because the Fortin Cali is out.

 

[kdmay]

You guys are an incredible resource.
I was reviewing this because the Fortin Cali is out.

If we can get gut shots of the Fortin Cali, we should be able to figure it out pretty quickly

 

[technomancer]

It’s a good question.

No one really knows what’s going on inside the Fortin Cali. He claims Violence mode engages a 4th gain stage, but there are only 3 12AX7s, so with a Cathode Follower, that only leaves 3 gain stages. And typically the Jose circuits (which I am presuming is the Cali reference) have Cathode Followers.

Now he could be using a plate fed tone stack and deriving the 4th stage that way, very possible. But it would be a completely different beast. Having said that, IIRC the Fortin Bones was plate fed, so it’s very possible. In which case, it would differ quite a bit from the Helios, Atomica and Friedman Small Box.

Incidentally, the new Helios Eclipse claims 6 gain stages for the Ecplise+ mode. I’ve always thought this was just diode clipping, but I could be wrong. The Wizard MTL has 6 gain stages, but with diode clipping and a feedback driven recovery stage (unique to this amp and the Jubillee), it’s another beast again!

That is exceptional. Thank you very much.

I was trying to discern how different or similar the Fortin Cali would sound from the Helios 50 or Friedman built Atomica.

Yeah I am curious to see what violence mode actually is. The base amp is 99% likely to be his Cali Marshall mod which is a Jose variant. I also take the fourth tube gain stage claim with a grain of salt though as the marketing for the Meshuggah claimed that initially as well and that is basically a 2204 with Jose-style diode clipping master, so 3 gain stages.

 

[FourT6and2]

Diodes do not equal a "gain stage." The original product description for the Meshuggah also said it had 4 gain stages. The description was later edited.

Gain is not the same thing as clipping or distortion. A "gain stage" must actually raise the signal level (i.e. cause an increase; that's what "gain" means. Think: muscle gains). Diodes do not cause an increase in gain. Rather, they clip the signal at a specific threshold.

I doubt anybody is going to post a gut shot of the new Fortin Cali, though. People tend to be emotionally invested in this stuff.

 

[technomancer]

Diodes do not equal a "gain stage." The original product description for the Meshuggah also said it had 4 gain stages. The description was later edited.

Gain is not the same thing as clipping or distortion. A "gain stage" must actually raise the signal level (i.e. cause an increase; that's what "gain" means. Think: muscle gains). Diodes do not cause an increase in gain. Rather, they clip the signal at a specific threshold.

I doubt anybody is going to post a gut shot of the new Fortin Cali, though. People tend to be emotionally invested in this stuff.

Yep. And there is no mistaking what is meant on this one since the description specifically says:
"Assignable VIOLENCE 4th tube gain stage for OD1 and OD2."

That said I'm not curious enough to spend $3k to find out

 

[FourT6and2]

Diodes do not equal a "gain stage." The original product description for the Meshuggah also said it had 4 gain stages. The description was later edited.

Gain is not the same thing as clipping or distortion. A "gain stage" must actually raise the signal level (i.e. cause an increase; that's what "gain" means. Think: muscle gains). Diodes do not cause an increase in gain. Rather, they clip the signal at a specific threshold.

I doubt anybody is going to post a gut shot of the new Fortin Cali, though. People tend to be emotionally invested in this stuff.

Yep. And there is no mistaking what is meant on this one since the description specifically says:
"Assignable VIOLENCE 4th tube gain stage for OD1 and OD2."

That said I'm not curious enough to spend $3k to find out

Me neither.
That said, the Super-Hi does sound fantastic and I have no regrets buying one. But it's an incredibly noisy amp with a lot of... well, let's call them "design quirks" lol.

 

[kdmay]

Diodes do not equal a "gain stage." The original product description for the Meshuggah also said it had 4 gain stages. The description was later edited.

Gain is not the same thing as clipping or distortion. A "gain stage" must actually raise the signal level (i.e. cause an increase; that's what "gain" means. Think: muscle gains). Diodes do not cause an increase in gain. Rather, they clip the signal at a specific threshold.

I doubt anybody is going to post a gut shot of the new Fortin Cali, though. People tend to be emotionally invested in this stuff.

+1

So many people confuse "gain" and "distortion". No possible way diode clipping can add gain, rather than are further distorting the signal.

Agree on the gut shots, but having said that I am sure at some point we will see details of this amp emerge and be very underwhelmed! (Think Messhuggah.....).

 

[Ringuz]

Diodes do not equal a "gain stage." The original product description for the Meshuggah also said it had 4 gain stages. The description was later edited.

Gain is not the same thing as clipping or distortion. A "gain stage" must actually raise the signal level (i.e. cause an increase; that's what "gain" means. Think: muscle gains). Diodes do not cause an increase in gain. Rather, they clip the signal at a specific threshold.

I doubt anybody is going to post a gut shot of the new Fortin Cali, though. People tend to be emotionally invested in this stuff.

Here the gutshots of mine ?

 

[FourT6and2]

Here the gutshots of mine ?

Thanks I had a Cali for a while too. That one actually has four stages.

 

[Techdeth]

I like the aggressiveness it gives when combined with tube warmth. +1 to what Dave said - it has to be done correctly in terms of location and what exact values of diodes are used.

The aggressiveness is the exact word I was going to use . Gives it that grind to rip through the speaker a little more . Good call

 

[Ringuz]

Thanks I had a Cali for a while too. That one actually has four stages.

What is the fourth stage Made of?Since there are 3 tubes only??

 

[technomancer]

What is the fourth stage Made of?Since there are 3 tubes only??

Simple, it uses a plate fed tone stack. So 4 tube gain stages and the phase inverter.

 

[PhilC]

What is the fourth stage Made of?Since there are 3 tubes only??

Each 12AX7 is dual triode. With 3 12AX7's you could have 4 gain stages assuming the 3rd tube is used as a phase inverter for the power section.

 

[FourT6and2]

What is the fourth stage Made of?Since there are 3 tubes only??

lol... nice try

 

[FourT6and2]

Here's another pic

 

[psychodave]

I even love the diode clipping in the Randall RG. ?

 

[RedPlated]

Another one here that’ll take diodes done right over a 4th tube stage.