Do you absolutely need a loadbox for recording?

[311boogieman]

That is something to discuss for amps with master volume.

Here is my JMP master set to 1 plugged into my soundcard.

I'm using NadIr plugin with God's Cab IR.

https://soundcloud.com/totoleheron/jmpdirect

Flac available for download (click on the arrow).

Sounds good.

Don't listen to all the haters. Just keep doing what you are doing. As a matter of fact, I'd turn it up a bit and get those power tubes cooking

 

[bananaladonpcp]

That is something to discuss for amps with master volume.

Here is my JMP master set to 1 plugged into my soundcard.

I'm using NadIr plugin with God's Cab IR.

https://soundcloud.com/totoleheron/jmpdirect

Flac available for download (click on the arrow).

Sounds good.

Don't listen to all the haters. Just keep doing what you are doing. As a matter of fact, I'd turn it up a bit and get those power tubes cooking

 

[bmi]

Either the guy is just dumb or is trolling.

Viva La France

"Vive la France."

Now if you don't know what can do frenchies you can check this thread (though the France is really going down actually and i'm afraid that we frenchies have entered in a destruction process. Destruction of our civilisation) :

http://www.kemper-amps.com/forum/index. ... 7&pageNo=4

But i think that i have to put a copyright for a new recording method and i should probably call it the frenchie/bmi recording method. For sure it will have a lot of success in studio.

By the way this thread is not a troll.

 

[bmi]

Perhaps you want to talk about what you said on TGP's forum about Shannon and sampling at 48khz?
Because that's a huge technical bullshit.

Not sure what you are referring to but if I said it I stand behind it. The Nyquist-Shannon sampling theorem is well-proven so I'm not sure what you are ranting about. If it weren't you wouldn't have been able to post that SoundCloud clip in your original post.

You know what you said. Basically you said that sampling at 48khz was enough so higher sample rates was irrelevant.

By the way i would like to know if FAS is working on a loadbox system.
It could explain why you spread fear here.

 

[bmi]

A 50W Marshall has an impedance ratio of 400 typically for the 8-ohm tap. The 4K input impedance of your sound card therefore will be multiplied by 400 resulting in 1.6 Megohms on the power tube plates. Even the tiniest bit of current through the power tubes will cause huge voltage fluctuations on the plates which can cause the insulation in the output transformer to fail. The longer you run it the higher the likelihood of failure.

IOW what you are doing is stupid and dangerous.

After half an hour of play the OT is completely cold. You have to tell me how the insulation of the transformer can burn if it is cold.

I will try to check what you say because that will not be the first time that you spread technical bullshit on internet like saying for example that 48khz is enough for sampling based on Shannon maths.

Temperature is irrelevant. The insulation fails because of the excessive voltage. It's called withstand or breakdown voltage. 1 mA through your output tubes will induce 1600 volts on the OT. That is enough to punch through the insulation.

Yes, you right, I spread "technical bullshit" on the internet. You on the other hand, don't.

Yes i'm right and you spread fear.

I spent 1 hour of tests and measurements this morning with my JCM2000.
I checked the output voltage (OT) and the plate voltage or the input voltage of the OT.

The JCM2000 is plugged first into my 4x12 (16 ohms) closed cab (JTM45 40th anniversary).
I'm using the 8 ohms output because i removed 2 tubes.
I set a very small power output on par with what can deliver a preamp output (noise of the strings cover the sound coming out of the cab).
Here are the first measures :
plate voltage/or OT input voltage : 471 V
max output voltage (OT) : 30 mv



Then i plugged the head into my soundcard (mic preamp input 4k ohms) and here are the results :
_ time zero
plate voltage or OT input voltage 479 V
max output voltage around 60 mv

_ after 10 minutes
plate voltage 480V
max output voltage around 60mv

_ 20 minutes
plate voltage 482 V
max output voltage around 60 mv

_ 30 minutes
plate voltage 479 V
max output voltage around 60 mv

_ 40 minutes
plate voltage 481 V
max output voltage around 60 mv

_ 50 minutes
plate voltage 483 V
max output voltage around 60 mv

_ 1 hour
plate voltage 480 V
max output voltage around 60 mv

I played riffs all this time.
The max output voltage is given by strumming hard the guitar during the measure. It goes from 56 to 63 mv.

I plugged back the head into the cab and i measured :
plate voltage 481 V
max output voltage around 27 mv

As i said previously at the end the OT is completely cold.

 

[bmi]

Here is a record after one hour.
https://soundcloud.com/totoleheron/jcmdi ... ing-method

The amp does hum after 1 hour but nothing extraordinary here, i think that tubes are not well matched.
It does hum with a cab too. Hum grows after half and hour when tubes are hot.

 

[JTyson]

But i think that i have to put a copyright for a new recording method and i should probably call it the bmi/frenchie recording method. For sure it will have a lot of success in studio.

By the way this thread is not a troll.

Oh, for sure you should do that immediately, I'm sure nobody has ever tried this before you thought of it. Pay no mind to the naysayer amp builders on the forum, they just dont want you to succeed. The name is perfect!
Carry on..

 

[bmi]

But i think that i have to put a copyright for a new recording method and i should probably call it the bmi/frenchie recording method. For sure it will have a lot of success in studio.

By the way this thread is not a troll.

I'm sure nobody has ever tried this before you thought of it.

I'm sure you tried that's why you knew that this would not work.

 

[crankyrayhanky]

Are you sure that growing hum is the tubes?
All jokes aside, methinks you are killing the transformer(s)

 

[bmi]

Are you sure that growing hum is the tubes?
All jokes aside, methinks you are killing the transformer(s)

As you can check there is no voltage or current issue.
As i said it does the same hum into the cabinet. This is not new.

But perhaps you're right, i'm killing the OT without any signs of anomaly. It's magic.
(Bias current is normal 31 mA)

 

[1big1]

makes me wonder if the op knows it's 1 and 3 and 2 and 4. please let us know what a fried dagnall smells like.

 

[bmi]

makes me wonder if the op knows it's 1 and 3 and 2 and 4. please let us know what a fried dagnall smells like.

Explain me why it should fry if voltage and current are ok?

 

[cliffc8488]

Your measurements are DC measurements and are irrelevant. The issue is high-voltage AC transients. Without a *correct* load there is a very strong chance that AC transients on the plates will be great enough to cause dielectric breakdown of the transformer insulation. When this happens arcing occurs inside the transformer. Over time this can cause the transformer to become unbalanced (leading to hum issues) or, worse, the transformer can fail.

Some amps have diode clamps to mitigate this (Trainwrecks) but most do not as they assume the user isn't dumb enough to run it without a load. Even then a diode clamp only clamps the negative transients.

Judging by the amount of hum in your clip I'd say you have already caused some damage to the transformer.

But you know everything so why bother arguing.

 

[1big1]

Your measurements are DC measurements and are irrelevant. The issue is high-voltage AC transients. Without a *correct* load there is a very strong chance that AC transients on the plates will be great enough to cause dielectric breakdown of the transformer insulation. When this happens arcing occurs inside the transformer. Over time this can cause the transformer to become unbalanced (leading to hum issues) or, worse, the transformer can fail.

Some amps have diode clamps to mitigate this (Trainwrecks) but most do not as they assume the user isn't dumb enough to run it without a load. Even then a diode clamp only clamps the negative transients.

Judging by the amount of hum in your clip I'd say you have already caused some damage to the transformer.

But you know everything so why bother arguing.

see above.

 

[cliffc8488]

Another thing is that an unloaded amp can easily oscillate at ultrasonic frequencies. Without the correct load the feedback network doesn't function as intended which can cause instability. This can damage the tubes and the OT.

 

[cliffc8488]

You know what you said. Basically you said that sampling at 48khz was enough so higher sample rates was irrelevant.

CDs only sample at 44.1 kHz. Amazing. Score: Nyquist-Shannon 1, BMI 0.

 

[bmi]

Your measurements are DC measurements and are irrelevant. The issue is high-voltage AC transients. Without a *correct* load there is a very strong chance that AC transients on the plates will be great enough to cause dielectric breakdown of the transformer insulation. When this happens arcing occurs inside the transformer. Over time this can cause the transformer to become unbalanced (leading to hum issues) or, worse, the transformer can fail.

Some amps have diode clamps to mitigate this (Trainwrecks) but most do not as they assume the user isn't dumb enough to run it without a load. Even then a diode clamp only clamps the negative transients.

Judging by the amount of hum in your clip I'd say you have already caused some damage to the transformer.

But you know everything so why bother arguing.

My first sentence was "That is something to discuss for amps with master volume."
Now you hear what you want to hear.

The question from the beginning is if issues occurs even with extremly low power/voltage/current when all seems to be ok. Not with high power.
The issue is high-voltage AC transients. Without a *correct* load there is a very strong chance that AC transients on the plates will be great enough to cause dielectric breakdown of the transformer insulation.
DC weares the AC signal and AC is small. I'm surprised that with a smaller AC you get transients which can borked the OT but if you say so.
I will try to check the transients.

The amp still work as it should when plugged into a cab.
There has always been a hum which increase with time. Of course when the signal is low the hum appears strong. Into a cabinet at higher level you don't care about it.

 

[bmi]

You know what you said. Basically you said that sampling at 48khz was enough so higher sample rates was irrelevant.

CDs only sample at 44.1 kHz. Amazing. Score: Nyquist-Shannon 1, BMI 0.

It's not a Shannon/bmi game. Shannon is right.

 

[ke2]

Your English is excellent, BTW

 

[1big1]