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sijan92

Can this technique be used to get a cranked tube amp sound in low volume?

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I currently own a DT25 combo and a Pod HD500X which I have connected via the Line6 Link cable. I am thinking of recording some music but the Dt25 is way too loud for my bedroom therefore I cannot mic it in high volume. Of course, if I do not crank it up, I would not get the sound I would want. The LVM is not enough for quality sound since it eliminates the power amp section of the amp. 

 

I was thinking of investing on an audio interface like the UX2 to record my music. My plan is to connect my amp to the audio interface through the Direct Out of the amp. If I follow this approach, I could disconnect the amp's connection with its cabinet so I wouldn't get any sound from the amp itself but I would get my sound from the monitors connected to the UX2. So if I have the amp's master volume amp cranked all the way up, I could adjust the volume from on my UX2 according to how I want but my recordings should sound as if it's coming from a cranked tube amp. Essentially, I would like to get the sound of a cranked tube amp sound in my recordings without disturbing my neighbors. Do you think this is a viable approach?

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Won't that just destroy your output transformer? You shouldn't run the amp wiyh the speaker disconnected, it'll destroy the amp.

 

The sound on the direct out is, I believe, a low level version of what's going to the speaker. If the speaker is silent, isn't the direct out silent too? Can't check, my amp is broken, but I think thats how it goes.

 

There is only one way to get the sound of cranked tubes, and that is to have cranked tubes. Placing an attenuator or dummy load across the amps output can let you reduce or eliminate the loud sound, but the more you reduce it like this the more the tone gets altered too.

 

Look into building an iso box or something, if LVM doesn't do it for you (doesn't do it for me anyway).

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Never a good idea for a tube amp...Running a tube amp without a load can burn up the output transformer. I would suggest you at least put a dummy load on the amp...A resistive load will keep the power amp loaded....But the tone will be different than with a cab...

 

https://www.parts-express.com/8-ohm-100w-non-inductive-dummy-load-resistor--019-020

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I hate to say it because I love using my HD500 with my DT25's... But for home recording, just go direct with the HD500.

It will give you more options overall - dual amp models, cabinet options, mic options, stereo..

 

I get a great signal off the DT25 XLR out, it's a nice recording / live mix send for sure.

 

But that being said, the only safe way to do what you want to do is to use a load box of some sort, in order to not destroy your amp.

That power needs to go somewhere. 

 

Not sure the exact term you would search for, something like these:

 

http://www.sweetwater.com/c1117--Attenuators_and_Simulators

 

http://www.sweetwater.com/store/detail/CabClone8

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Thank you for the feedback! So can anyone confirm that if I run the tube amp with a load box, I would be able to hear the sound of cranked power amp tubes with adjustable volume on my interface monitors? I am not sure if the Direct Out would be silent if I use the amp with load box. I know Pod HD 500 itself is an excellent device for recording but I would really like to utilize my DT25 tones in my recordings to get a richer sound. 

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there is no safe way to run a tube amp silently.  Power soaks will help to lower the volume but definitely affect tone, I know, I tried it.  Not worth the effort.  As mentioned above, you could build an isolation cabinet which is a sealed, soundproofed box which contains your amp and speaker.  You would have your guitar cable in and the direct out but otherwise the box is sealed.  It should be quiet enough but still no guarantees. 

 

If this was a simple thing to do, everyone would be doing it.  It is not.  Don't risk your valuable amp just for the supposed tube goodness.  There are plenty of good tones available from the POD direct for recording. You gain nothing for recording purposes doing what you propose but risk destroying a great amp.

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Thank you for the feedback! So can anyone confirm that if I run the tube amp with a load box, I would be able to hear the sound of cranked power amp tubes with adjustable volume on my interface monitors? I am not sure if the Direct Out would be silent if I use the amp with load box. I know Pod HD 500 itself is an excellent device for recording but I would really like to utilize my DT25 tones in my recordings to get a richer sound. 

If you just go direct out on your hd500x then you can monitor the actual tone you're recording as you record it--at any volume you like, through headphones or monitor speakers!  I think the Dt amps do sound better, but you can come close with the HD, and sitting in the mix it's tough to hear the difference.

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Didn't Eddie Van Halen get his entire tone by slaving a Marshall head into a dummy load box? I read something along these lines:

 

"use a dummy load box after the Marshall head, in effect making the Marshall a preamp for the entire system. The output of the load box would then run through his effects which would then be sent to the input stage of a power amplifier."

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Didn't Eddie Van Halen get his entire tone by slaving a Marshall head into a dummy load box? I read something along these lines:

 

"use a dummy load box after the Marshall head, in effect making the Marshall a preamp for the entire system. The output of the load box would then run through his effects which would then be sent to the input stage of a power amplifier."

 

Probably at some point...He has done just about everything you can do...I know at one time in the early days he did take a line off the head the run the FX stack...and the power for that was a SS Crown power amp as I recall...Probably several incarnations there...He intentionally mismatched the cab load on the Plexi power amp for the dry tone using a wirewound pot...basically, he added some adjustable resistance to the speaker line...It's a global tone control...impedance higher than the tap means brighter....impedance lower than the tap tends to darken some...

 

This gets really complicated with the Variac running a lower voltage as the impedance of everything changes some with that...

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Probably at some point...He has done just about everything you can do...I know at one time in the early days he did take a line off the head the run the FX stack...and the power for that was a SS Crown power amp as I recall...Probably several incarnations there...He intentionally mismatched the cab load on the Plexi power amp for the dry tone using a wirewound pot...basically, he added some adjustable resistance to the speaker line...It's a global tone control...impedance higher than the tap means brighter....impedance lower than the tap tends to darken some...

 

This gets really complicated with the Variac running a lower voltage as the impedance of everything changes some with that...

 

Eddie will also tell you he blew up plenty of amps along the way and discovered his variac trick by accident too.  He was a hands on tinkerer (genius?) but don't extrapolate his techniques to something you can do safely at home kids!

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Back then with all-analog amps you could get away with the Variac/etc. Todays amps esp. w/ digital on board, no way.

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Good job mentioning that. I sure hope no one tries a Variac on an DT running at 90 volts...Certainly that would not be a good idea...And safety is the primary concern...

 

In terms of running a tube amp safely silent which is the topic on this thread...One can run ANY tube amplifier silent safely...You need only a dummy load to do so. Make sure that the rating of the dummy load is 4 times the amplifier rating...A properly rated resistive load is actually a bit safer for the amplifier's output transformer than real speakers are since speakers more often tend to fail to open circuit...If you plan to run your amplifier near max power, you must use a load that is at least double the rating...four times is better...Tube audio power amplifiers can actually exceed their rated output by 4 times in fast transients depending on the design...Running sustained at full power, they tend to nearly double...So that DT-25 could lay down as much as 50 watts with the master dimed...fast transients as high as 100 watts...So you use a 100 watt dummy load or attenuator on a DT-25 and you are actually safer than you are with the stock speaker by 10 watts...

 

People that generally experienced a failure doing this are the ones that used one a dummy load(or attenuator) matched to their amplifier's output ratting and dimed the output, melted the load and wondered why their amp blew up...They just did not know any better...I think most of those guys are former hotplate users... ;)

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A resistive load won't sound good, though. It needs to be inductive too. The speaker has an effect on the poweramp just as the poweramp effects the speaker...that's why attenuators and dummy loads cause tonal changes due do lack of, or different inductance.

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A resistive load won't sound good, though. It needs to be inductive too. The speaker has an effect on the poweramp just as the poweramp effects the speaker...that's why attenuators and dummy loads cause tonal changes due do lack of, or different inductance.

 

That was why I suggested a Weber Mass...It's a real speaker motor..."Reactance" is the word I think you meant...A Weber MASS has reactance...resistors do not...

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That was why I suggested a Weber Mass...It's a real speaker motor..."Reactance" is the word I think you meant...A Weber MASS has reactance...resistors do not...

 

Because speakers have coils but not capacitors, I think you're both essentially correct:

 

"In electrical and electronic systems, reactance is the opposition of a circuit element to a change in current or voltage, due to that element's inductance or capacitance. A built-up electric field resists the change of voltage on the element, while a magnetic field resists the change of current."

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I'm pretty sure the term I mean is inductance. Reactance is the opposition to changes in current (or voltage) caused by inductance (or capacitance).

 

A standard (high power) resistor can work as a dummy load as it offers resistance, but not inductive reactance. A coil, like in a speaker, is also inductive. Since tube amps are current sourcing, anything you connect which is inductive has a noticable impact on the signal, an impact that a simple resistor does not. The result of connecting something in.uctive is reactance, which is expected by the designer of the amp. So without inductance the dummy load causes tonal changes. This why the expensive attenuators are built on coils and motors, since they have inductance (tone preserving) as well as resistance (volume lowering).

 

So when I said "A resistive load won't sound good, though. It needs to be inductive too" I could have added "to create the required reactance".

But a coil, or the webber or whatever does not have reactance. It only creates a reactance when you pass current through it, because it is inductive.

 

I love splitting hairs ;)

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A Weber MASS is a speaker you ninny muggins :P ....pretty sure speakers have always been reactive loads...But if you don't think so, that's fine...enjoy!

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More stuff I need to read up on!

 

http://www.tedweber.com/atten.htm

 

"Some Weber Attenuators use power resistors to effect a purely resistive load on the amp. These attenuators are much like the other attenuators on the market, and provide a less natural sounding tone when heavily attenuated. Our resistive models are the Low Power Load Dump, Mega Dump, and Headphone Tap.

 

Other Weber Attenuators utilize an actual speaker motor to apply a reactive load on the amp. The attenuators are unlike any other on the market, and provide a much more interactive, natural sound when in use. They affect the tone less than the resistor-based models. The speaker motor units are the MASS, MiniMass, MicroMass, Stereo MASS, MASS 150, MASS Lite, and Power Tap."

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Anyone tried using the Mesa-Boogie "Cab Clone" for this kind of application?
 

http://www.sweetwater.com/store/detail/CabClone8

 

"The Mesa/Boogie Cabclone is a speaker cabinet simulator and load box that gives you entirely new ways to use your guitar amplifier on stage or in your studio. Plug your amplifier's speaker output to the Cabclone, and you can connect your amp's tone directly to a mixing console, mic preamp, or even direct to your recording device. Three different cabinet simulation voicings let you emulate the sound of open-back, closed-back, and "vintage" speaker cabinets. You won't need to lug a speaker cabinet with you to get outstanding tone from your amplifier, with the Mesa/Boogie Cabclone."

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