New Preamp Day - ISP Theta

Discussion in 'Gear & Equipment' started by mnemonic, May 27, 2018.

  1. mnemonic

    mnemonic Custom User Title

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    This arrived earlier in the week, kind of an impulse purchase, since I do see it recommended pretty much any time someone wants a high gain solidstate amp or high gain preamp, but there are almost no decent clips out there of it.

    What swayed me was that it's an interesting concept. The EQ is flat when the controls are flat, and the midrange control is sweepable with a real wide range. It also has a built-in ISP Decimator noise gate and you can run the clean channel into the gain channel so that it works as a boost for the gain channel.

    The EQ has a really wide range, plenty of cut or boost available from all the bands.

    I found it pretty easy to get a good tone from, its pretty clear and punchy sounding, and it responds very well to a boost pedal like an overdrive. Using the clean channel as a boost for the gain channel is tricky though, the clean channel EQ is very sensative in this setup, and its easy to make it sound bad. For instance turning the bass down to make it tighter, it goes from woofy and loose to overly thin and quacky really quickly. Also, its really noisy when using the clean channel as a boost. The decimator works really well to get rid of the noise, but I tend not to like super gated tones, I tend to leave them set low, or off so I can work more with dynamics. When used like a normal preamp (without using the clean channel as a boost into the gain channel) its pretty silent though.

    Since the EQ is flat with the controls at noon, I found the best sounds are by turning all the EQ controls up a bit. I'm not sure why, but the EQ here doesn't seem to mess up the response. For instance with some amps, if you turn up the bass too high, it gets flubby and loose, however with the Theta, it doesn't seem to loose tightness as I turn up the bass, which is cool. Turned up all the way, it almost sounds like I'm running a subwoofer, so its nice to have more than I would ever need on tap.

    The clean channel is really good too, which was a surprise. Though I think I'm pretty easy-to-please when it comes to cleans, I also really like my 3 channel Dual Rectifier's clean channel, and when set up right, my Jet City JCA50 also has nice cleans. The clean channel on the Theta is super clean, even with the gain at 10, no breakup to be found. But again, it takes a boost well. Given how tweakable the EQ is, it takes distortion pedals well too, like my BE-OD pedal. Though the gain channel of the Theta sounds better than the BE-OD anyway.

    I've ran it into my 2/50/2, the fx return of my Dual Recto and into the old Matrix poweramp I use for my Axe FX, and I can get great sounds with all of them. I think it keeps up fine with the Dual Recto as far as heaviness and chugginess. I'm definitely really glad I didn't sleep on this pedal.

    Since there are so few clips out there, I recorded something, just me playing pretty much the same riff over and over while turning knobs, recorded with an Iphone camera, so nothing special. I still haven't found my SM57, but its been years since I mic'd a cab so theres a good chance it would sound worse than an iphone camera.

    Also, I think the iphone camera does a good job of getting across the aggression available from the preamp. The audio compresses a lot when there's a lot of bass (and I like bottom-heavy tones so that doesn't help), but at least iphone camera mic's don't seem to clip easy.



    There's also some clean near the end with a strat. I don't think the clean really came through as good as it sounds in the room though.
     
  2. Bearitone

    Bearitone SS.org Regular

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    So, if you wanted to, you could have two separate channels (clean and dirty) with two separate EQ’s right?
     
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  3. HeHasTheJazzHands

    HeHasTheJazzHands SS.org Regular

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    Yup, but it's kinda tricky because you have to engage the preamp and disengage the distortion. The pedal has inputs for external footswitch controls, and the preamp and distortion control are on the same jack, so I wonder if you can rig up a footswitch to do that?
     
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  4. Bearitone

    Bearitone SS.org Regular

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    Eh, i’d just hot glue a metal bar across both buttons and stomp on the bar :lol:
     
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  5. thetourist

    thetourist SS.org Regular

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    Tasty tones!

    I got one of these a few months ago, with the intention of running it straight into a Yamaha THR10. (I thought it was a good idea at the time. :ugh:)
     
    Last edited: May 28, 2018
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  6. mnemonic

    mnemonic Custom User Title

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    Yep, just have to hit two buttons to switch from drive channel to clean channel.

    I think a seperate footswitch could be rigged up to switch channels using just one click, using the remote jack on the back of the Theta like you say. I might look into that at some point.
     
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  7. Kyle Jordan

    Kyle Jordan Ace of Knaves

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    Good stuff man. Thanks for the video.
     
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  8. cGoEcYk

    cGoEcYk SS.org Regular

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    I own one and run it into the power section of my Mesa Bass 400 (6x6550) into an Emperor 2x12 with Legend V12's. You can definitely get some ripping tight dry high gain tones that are usually only available in much more expensive units. I pretty much just use on evil gain tone on it (cleans are bit too clinical for me).
     
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  9. devastone

    devastone SS.org Regular

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    More like 1-1/2 channels since you can switch gains on the dirty channel as well. I had one a few years ago and had a similar experience with using the clean as a boost for the dirty channels. The EQ settings that worked best to use the clean channel as the "clean" channel weren't the same as the ones that worked best as a booster, I just used an OD pedal to boost either and I made a custom footswitch that plugged into the footswitch jack of the Theta. It had 2 buttons, 1 for clean/dirty, the other for gain 1/gain 2 on the dirty channel.
     
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