NAD: Fortin Evil Pumpkin

[novosibir]

I run an MXR 10-band in the loop of my amps and pull that 16K slider down. This reduces that super high-end fizz many people dislike. Because the neighboring slider is 8K, the curve probably extends up from there. Whatever it's doing, it's working for me

Then each control range obviously has a very large bandwidth with a slope of presumably 6dB/octave, which means that the 16 kHz range reaches very far up (which no one hears and no guitar speaker transmits anyway), but also reaches very far down, where it dampens the hairy fizz.

Yes, it has individual bias.

That's cool
If I were you, then my first try would be a pair of NOS RFT EL34 and a pair of NOS GE 6550A or a pair of Svetlana =(C)= 6550

Your designs are obviously amazing. The build quality is fantastic. You are a wealth of information and I learned a lot from you back when Metro Forum was still active. It really does suck when someone else copies something you worked hard to create. It's happened to me before too. I don't know if you remember, but you even sent me parts in the past.

Thank you for the flowers!

 

[Eazy-ESP]

Guitar speakers usually transmit hardly any frequencies beyond 6.5 kHz and drop from there with a slope of about 18dB/octave.
What is the point of lowering at 16 kHz?
Or is that a typo and you meant 6 kHz?


Does the amp have separate bias controls for the inner and outer power tubes?
Because EL34 and 6L6 require completely different bias settings.


I'm happy for you that you're so very satisfied with this amp
The fact that the amp has "Girth" & "Grind" controls in front of the gain control makes me suspect with almost certainty that Mike has once again adapted my circuit concept from the Dino, as he once did with the Natas and the Randall Satan.
The Sweep control is the extended version of the Body switch of the Dino. I have two switchable resistors, with Sweep exactly this point is adjustable via pot

In the summer of 2021, I ordered an EP from a large German music store because I wanted to find out how much of my concepts Mike had adapted again this time.
No, I didn't want to keep the EP permanently afterwards, but wanted to return it within the 30-day period.
However, since the delivery of the EP was postponed again and again every few months, I canceled my order 2 years later.
In the meantime, however, I don't care anymore, because I know that Mike did it again, even without checking it myself, because he never had own ideas

EDIT: Though there is one more thing that would interest me...
...whether Mike has adapted my Dino's Scream channel for the EP again this time, like he did before...
... or whether this time he chose the British HotRod channel, which is actually more popular among metal players.
However, it's no longer worth the effort to check an EP just to find this out

I hesitate to go there because I don’t want the pile on or for your haters to spam another thread. Plus I’ve been enjoying your reinvigorated posting with great technical knowledge…

…but the irony and humour to me of you of all people cancelling an amp order because it was taking too long. Just could not be missed.

 

[ners]

Pretty sure the human range for hearing is 20hz-20khz and that speakers can produce within that entire spectrum.

https://celestion.com/product/g12m-greenback/

I don't build amps though so *shrug*

 

[thegame]

Helmut has lost a lot of hearing. Court hearings that is.

 

[CDawg]

Pretty sure the human range for hearing is 20hz-20khz and that speakers can produce within that entire spectrum.
View attachment 430120
https://celestion.com/product/g12m-greenback/

I don't build amps though so *shrug*

Yes human hearing is about 20-20,000 hz and that would be the range used for amps/speakers in a hifi rig but for a guitar amplifier with Celestions the frequency range is only efficient around 75-5000Hz because of the speaker choice.

 

[FourT6and2]

…but the irony and humour to me of you of all people cancelling an amp order because it was taking too long. Just could not be missed.

That's exactly what I was implying lol...

 

[FourT6and2]

Pretty sure the human range for hearing is 20hz-20khz and that speakers can produce within that entire spectrum.
View attachment 430120
https://celestion.com/product/g12m-greenback/

I don't build amps though so *shrug*

Absolutely.

 

[novosibir]

Pretty sure the human range for hearing is 20hz-20khz and that speakers can produce within that entire spectrum.
View attachment 430120
https://celestion.com/product/g12m-greenback/

I don't build amps though so *shrug*

I know this graphic, but it confirms my statement rather than refutes it.
The interesting range of the guitar tone spectrum starts at 80 Hz and ends just above 5 kHz.
In this range, this speaker has a sound pressure of at least 93dB.
In the range from 2 kHz to 4 kHz we even have a sound pressure of 105 dB.
From 4.5 kHz the sound pressure drops steeply and at 7 kHz it is just a pitiful 78dB
That's a difference of 27dB
If you increase the sound pressure by 6dB, you will perceive it as twice as loud as before.
Conversely, if the sound pressure is reduced by 6dB, you will only feel it half as loud as before.
If the sound pressure is reduced by 12dB, it is only a quarter as loud as before.
If the sound pressure is reduced by 18dB, it is only an eighth as loud as before.
If the sound pressure is reduced by 24dB, it is only one sixteenth as loud as before.
Those of you who are still able to calculate with logarithms will come to the conclusion that if the sound pressure is reduced by 27dB, it is actually only perceived to be 4% as loud as the dominant frequency range of 2-4 kHz.

Do you really think that you can hear frequencies of 7 kHz or higher, even though they are only 4% of the loudness of the frequencies of the dominant range of 2-4 kHz?
In addition, that in the range of 7 kHz and higher there are no longer any (loud) fundamental tones of the guitar, but only the quieter overtones, and these only with a miserable 4% sound pressure?
If you really believe that, then you might give bats listening lessons.

 

[FourT6and2]

Yes human hearing is about 20-20,000 hz and that would be the range used for amps/speakers in a hifi rig but for a guitar amplifier with Celestions the frequency range is only efficient around 75-5000Hz because of the speaker choice.

But they still produce frequencies above that. And an EQ in the loop will absolutely kill those high-end fizzies. I really don't care about the semantics of exactly what frequencies they are. What I know is that using EQ and pulling down the relevant sliders, I get the sound I like.

 

[Eazy-ESP]

That's exactly what I was implying lol...

I thought as much, but figured I’d be the unsubtle mallet.

 

[novosibir]

I hesitate to go there because I don’t want the pile on or for your haters to spam another thread. Plus I’ve been enjoying your reinvigorated posting with great technical knowledge…
…but the irony and humour to me of you of all people cancelling an amp order because it was taking too long. Just could not be missed.

That's exactly what I was implying lol...

Tell me only one reasonable reason why I should keep the order of an amp which I never wanted to play or keep it anyway, but after two years had lost interest in finding out how much of my intellectual property Mike Fortin actually implemented in it again.

 

[Eazy-ESP]

Tell me only one reasonable reason why I should keep the order of an amp which I never wanted to play or keep it anyway, but after two years had lost interest in finding out how much of my intellectual property Mike Fortin actually implemented in it again.

I think you’re missing the humour here. Might be a German thing.

 

[ners]

I know this graphic, but it confirms my statement rather than refutes it.
The interesting range of the guitar tone spectrum starts at 80 Hz and ends just above 5 kHz.
In this range, this speaker has a sound pressure of at least 93dB.
In the range from 2 kHz to 4 kHz we even have a sound pressure of 105 dB.
From 4.5 kHz the sound pressure drops steeply and at 7 kHz it is just a pitiful 78dB
That's a difference of 27dB
If you increase the sound pressure by 6dB, you will perceive it as twice as loud as before.
Conversely, if the sound pressure is reduced by 6dB, you will only feel it half as loud as before.
If the sound pressure is reduced by 12dB, it is only a quarter as loud as before.
If the sound pressure is reduced by 18dB, it is only an eighth as loud as before.
If the sound pressure is reduced by 24dB, it is only one sixteenth as loud as before.
Those of you who are still able to calculate with logarithms will come to the conclusion that if the sound pressure is reduced by 27dB, it is actually only perceived to be 4% as loud as the dominant frequency range of 2-4 kHz.

Do you really think that you can hear frequencies of 7 kHz or higher, even though they are only 4% of the loudness of the frequencies of the dominant range of 2-4 kHz?
In addition, that in the range of 7 kHz and higher there are no longer any (loud) fundamental tones of the guitar, but only the quieter overtones, and these only with a miserable 4% sound pressure?
If you really believe that, then you might give bats listening lessons.

Yes? I mean, no doubt guitar is a mid range instrument but there's all sorts of little harmonics or pick attacks that generate audible tone above 7khz. Not to mention the lowest dB of that example greenback I posted was around 70dB, which is still as loud as a vacuum cleaner or something; might not be enough for rock'n'roll but extremely audible and absolutely something recording engineers have to worry about (given cymbals are in that 7k+ range).

 

[novosibir]

Yes? I mean, no doubt guitar is a mid range instrument but there's all sorts of little harmonics or pick attacks that generate audible tone above 7khz. Not to mention the lowest dB of that example greenback I posted was around 70dB, which is still as loud as a vacuum cleaner or something; might not be enough for rock'n'roll but extremely audible and absolutely something recording engineers have to worry about (given cymbals are in that 7k+ range).

Can you hear the vacuum cleaner clearly when you're playing loudly with the guitar over an amp?
Or only when you stop playing and dampen the strings?

 

[Meeotch]

I have the MXR 10-band, as well many other EQ's. I also hear high frequency attenuation when I lower the 16khz slider, and I think it is likely more to do with the broad bandwidth of that slider, and that slider's effect on the neighboring 8k slider, and less to do with actively cutting 16k.

This is easy to understand, because if you use a parametric eq and target 16k with a very narrow bandwidth, the adjustments can be imperceptible.

But yeah the numbers don't really matter if the tool is doing the job!

 

[FourT6and2]

I have the MXR 10-band, as well many other EQ's. I also hear high frequency attenuation when I lower the 16khz slider, and I think it is likely more to do with the broad bandwidth of that slider, and that slider's effect on the neighboring 8k slider, and less to do with actively cutting 16k.

This is easy to understand, because if you use a parametric eq and target 16k with a very narrow bandwidth, the adjustments can be imperceptible.

But yeah the numbers don't really matter if the tool is doing the job!

Exaaaactly.

It really doesn't matter what actual frequencies are being affected. What matters is when I move the "16KHz" slider on my EQ, I get the sound I want. And yes... the nearest neighbor on the pedal is 8KHz. So obviously the curve from there all the way to 16K is being affected in some way.

 

[glpg80]

We can only hear up to 20KHz but constructive and destructive harmonic interference is responsible for audio frequencies we do hear that occur at frequencies well above what we cannot hear.

And Mike is right much of the time once the core tone is made you may or may not want that happening all the way to the phase inverter and choose to lop it off ahead of time. Personal preferences really. I like the fizz at low volume because it typically cleans right up after you throw some volume at the amp. 5150’s are a perfect example.

 

[CDawg]

But they still produce frequencies above that. And an EQ in the loop will absolutely kill those high-end fizzies. I really don't care about the semantics of exactly what frequencies they are. What I know is that using EQ and pulling down the relevant sliders, I get the sound I like.

That is true and there's nothing wrong with that. I'd do the exact same thing and so would just about everyone else.

I'm just saying it is not efficient. You might be able to get what you want; but you will never be able to produce a deep low end or a high treble with any efficiency without all the hardware in a system. Most people playing a musical instrument wouldn't care. If a person was into hifi it's going to matter a lot because they're likely operating at 20-20,000 hz or 10-50000 hz for a good hifi rig vs 80-5000 hz for guitar.