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800 Watt Amp into Audio Interface without Cab ?
Old 9th September 2019
  #1
Here for the gear
 

800 Watt Amp into Audio Interface without Cab ?

Hi there folks! long time lurker of the forums, first time poster. Hopefully this is in the right spot. I've done a lot of googling of this topic, searched the forums, spoken to a few pro audio folks locally and nobody seems to have the answer for me. Hoping some folks here can help.

I am looking to take my vintage solid state Peavey Super Festival Amp Head (800W / 4Ohms) and connect it directly into my audio interface without having to mic cabs. Here's the specs https://assets.peavey.com/literature/manuals/f800bg.pdf. The amp sound + distortion is beautiful, I'd love to capture it and use it with different instruments.

The Audio Interface is a UAD Apollo Twin MK 2 https://www.uaudio.com/audio-interfa...twin-mkii.html

Does anyone have any perspective on the best way to accomplish this without using cabs + mics ?

I've seen some folks using the Palmer PDI 03 Speaker Simulator https://www.palmer-germany.com/en/pr...es/5100/pdi-03 but it says its rated for 100 Watts so i'm worried my 800 Watt amp might not be a good match. Although maybe i'm not understanding that correctly.

I've also looked at the UA OX Box https://www.uaudio.com/hardware/ox.html but its made for tube amps so its not a good fit.

Any help here would be greatly appreciated, i'm a little lost. Apologies if any of the explanation didn't make sense, i'll be happy to clarify the best I can. thanks!
Old 9th September 2019
  #2
Lives for gear
I don't normally get involved in guitar amp issues, but lately the guitarists I'm working with are pulling me that way. In this case, this seems a more straightforward watts-ohms-amps issue, and there's something approaching good news for you:

The last two pages of the Peavey PDF document show that it can deliver 400W RMS into a 2-ohm load. The spec sheet goes on to show a chart of its output wattage at 4-ohms, and 8-ohms, offering 150-watts at 1% distortion at 8-ohms and 170-watts at 5% distortion. [Oh, would all manufacturers be so forthcoming with their details!]

The immediate implication is that the 16-ohm Palmer product would be well within its 100-watt specification, ~85 watts at 5% distortion with a 16-ohm load on the Peavey. The second implication is that if you're not producing sine waves with your guitar, the duty cycle won't put you anywhere near max RMS ceiling of the Palmer box, and the 8-ohm version would *probably* do fine.

Remember, this is a paper-calculation assessment, as I generally try to offer direct experience in my posts. I don't have a Peavey or a Palmer. The folks over in the "So Many Guitars" part of GS have a quite a lot of experience with this stuff. I'm sure they'll show up with some commentary soon.
Old 9th September 2019
  #3
Agreed, moved to So Many Guitars, So Little Time - I think OP will find better luck in here than on Music Computers.

Old 10th September 2019
  #4
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enorbet2's Avatar
Hello reggiwatts. Since it is highly doubtful that you are overdriving that power amp which would imply all the distortion is in the preamp, there may be a far easier solution. It is a SS power amp, right? If it is, then no load need be attached as long as the Master Volume is turned down to Zero - No Input == No Output. This is only helpful if it already has some sort of PreAmp Out jack or you know someone who could install one. I couldn't find a schematic so I can't be more specific than this but this is true of all SS power amps. ASo as long as it has a Master and an output before the Master, ur in business real cheap.
Old 12th September 2019
  #5
Quote:
Originally Posted by enorbet2 View Post
Hello reggiwatts. Since it is highly doubtful that you are overdriving that power amp which would imply all the distortion is in the preamp, there may be a far easier solution. It is a SS power amp, right? If it is, then no load need be attached as long as the Master Volume is turned down to Zero - No Input == No Output. This is only helpful if it already has some sort of PreAmp Out jack or you know someone who could install one. I couldn't find a schematic so I can't be more specific than this but this is true of all SS power amps. ASo as long as it has a Master and an output before the Master, ur in business real cheap.
EDITED: If it's the same Peavey Festival 800 I've been able to find online, it does not appear to have a preamp out. Since this is the case you cannot use it in the manner suggested unless you're willing to risk burning out the input stage of your interface and possibly blowing the amp when the interface input burns and shorts out.

You also can't use any commercially available power soak/load that I've ever heard of because there simply are no commercially available load boxes rated for an 800 watt amp.

You should also be aware that Peavey amps of that vintage are somewhat less than reliable and don't like having weird stuff connected to the output. If it's a newer version I didn't see online that does have a preamp out, use that and leave the speaker outputs disconnected.
Old 12th September 2019
  #6
Here for the gear
 

The bad news here is that 95% of that juicy OD goodness will likely be lost by going direct amp > interface. A guitar amp you love tends to be greater than the sum of it's parts. Remove one of it's parts and the magic is gone.

If it were me I would:
1. Isolate and mic the amp.
2. Just run direct and find an awesome amp sim that I like. It will probably sound different but sometimes you find pure gold in those files.
Old 12th September 2019
  #7
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enorbet2's Avatar
I've never tried it other than to put an ohmmeter on a slab to see if the results were even in the ballpark (they can be) but I've read that shops for very high power amps use benches where the bench tops are made from expanded metal... you know, the stretched "X"/Diamond pattern slabs, where they get 2, 4 and even 8 ohm loads of extreme power handling due to both the mass involved and the natural airflow through "the diamonds". They need to be fairly long benches but it does work for cheap, reliable high power loads.. The only reason I never made a bench from my slab was I have a rather large load box (substantially smaller than a bench though) I constructed with military resistors that handles up to 600 watts, but I do wish I'd read about expanded metal first. I'd have saved a buncha bux..
Old 15th September 2019
  #8
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grannis's Avatar
Speaking as someone who never mics up amps any more, I can tell you I’ve used one of those amps, and its mojo surprised the hell out me. Don’t risk losing that, mic it up!
Old 15th September 2019
  #9
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ponzi's Avatar
Is 800 watts gonna be enough?
Old 4 weeks ago
  #10
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Quote:
Originally Posted by ponzi View Post
Is 800 watts gonna be enough?
800, 801, whatever it takes …
Old 4 weeks ago
  #11
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kennybro's Avatar
Quote:
Originally Posted by ponzi View Post
Is 800 watts gonna be enough?
Topic:
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