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ISP Technologies Theta Preamp Distortion Pedal with Decimator Noise Reduction

Electric Guitar Preamplifier Pedal, with 2 x Gain Stages, 2 x 3-band EQ, Over 160dB of Gain, and Decimator Noise Reduction
ISP Technologies Theta Preamp Distortion Pedal with Decimator Noise Reduction
$391.00
6 months
$65.17/month with 6 month financing
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While this isn't an item we normally stock, we can still get it to you as fast as possible due to our great relationship with ISP Technologies. Go ahead and place your order and we'll follow up shortly to let you know when to expect it. Estimated September 2025.

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ISP Technologies Theta Preamp Distortion Pedal with Decimator Noise Reduction
We Can Get It!
$391.00
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Much More Than a High-gain Powerhouse

ISP Technologies created the Theta Preamp Pedal to bring you the aggressive gain and sustain from their acclaimed Theta amplifier, in a pedalboard-friendly design. We're talking outrageous gain - over 160dB of gain, when you use both the Pre-distort Preamplifier and High Gain Distortion sections together. Or just the Pre-distort Preamplifier stage's 3-band EQ for sweet tone shaping independent of the high-gain stage, for extra versatility. And with its +/-15-volt power supply, you've got an amazing amount of headroom for more dynamic tones with the ISP Technologies Theta Preamp Pedal.

ISP Technologies Theta Preamp Pedal at a Glance:
  • Over 160dB of gain for undeniably aggressive tone and sustain
  • Decimator G-string II circuit means ultra-quiet operation
  • More headroom means more punch, impact, and tonal tenacity
Over 160dB of gain for undeniably aggressive tone and sustain

It may seem like a bit much, but between the two gain stages on the Theta Preamp Pedal you've got over 160dB of gain on tap. You can use the Pre-distort Preamp stage either for clean tone-shaping (with the 3-band EQ) or as a rich-sounding overdrive. The High Gain Distortion stage gives you 3-band tonal control too, so it's easy to really dial-in your ideal tones on the Theta Preamp Pedal.

Decimator G-string II circuit means ultra-quiet operation

The award-winning Decimator G-string II noise-reduction circuit on the Theta Preamp Pedal is what keeps this high-gain monster from sounding like a continuous static discharge. In fact, the Decimator technology provides more than 80dB of noise reduction. And the big deal with this generation of the Decimator technology is the incredibly smooth release response, which means that you don't hear the noise reduction working at all - you just notice how quiet your rig is when you're not playing.

More headroom means more punch, impact, and tonal tenacity

The Theta Preamp Pedal packs an internal +/-15-volt power supply, which gives it three times the headroom of a typical 9-volt pedal. More headroom means more dynamics, and that means more punch, impact, and nuance in your tone. So even if you have the gain on the Theta Preamp Pedal cranked, you'll still have a powerful, aggressive tone with a ton of character.

ISP Technologies Theta Preamp Pedal Features:
  • High-gain preamplifier pedal for electric guitar with two gain stages
  • Pre-distort Preamp stage can be used for clean tone shaping, or as an overdrive
  • High Gain Distortion stage provides incredible distortion and sustain
  • Use both stages together for up to 160dB+ of gain
  • Independent 3-band EQs with sweepable mids for each gain stage
  • Decimator G-string II circuit gives you over 80dB of noise reduction for quiet high-gain operation
  • +/-15-volt power supply gives you incredible headroom for more dynamic, punchy tones
The Theta Preamp Pedal packs more gain than you'll find in any other preamp pedal!

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Tech Specs

  • Type: Guitar Preamp and Distortion
  • Controls: Demicator
  • EQ: 2 x 3-band EQ, 2 x sweep
  • Inputs: 1 x 1/4"
  • Outputs: 1 x 1/4"
  • Other I/O: 2 x 1/4" TRS (G1/G1, Pre/Dist)
  • Power Source: 9V AC power supply (included)
  • Height: 1.9"
  • Width: 7"
  • Depth: 5"
  • Weight: 2.2 lbs.
  • Manufacturer Part Number: THETA PREAMP PEDAL

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Reviews

Rated 5/5
Excellent high gain tone
As far as I'm concerned, ISP is the champion of the high gain arena. The Theta, in all of it's variations, is a tone machine. Do not let the pedal format fool you - it's the same tone from the head and rackmount preamp. Fender cleans are available in the preamp section, searing Mesa Rectifier and mod'd JCM800 tones are easily dialed in when distort 1/2 are activated..and then of course you have the option of cascading the preamp into the distort channel acting as a built-in overdrive. I don't see myself ever getting rid of this pedal and as a result I won't ever need a tube amp again.
Rated 5/5
Wow!!! Amazing
Thought about trying The ISP Theta pedal for a while. I have used tube amps for years and did not think I would be that impressed,But I was. I can honestly say I have given up the tube amp thing for good.Love the fact the ISP products are made in the USA. I like to use an american made product when I can. I will be purchasing a ISP Theta Pro in the very near future. ISP products are worth every penny.I have an original Decimator pedal that I have used for over 10 years and a Vector 210 sub. Fantasic products. I'm a ISP fan for life.
Rated 5/5
Pro Guitar tone and boost
Gain 1 is smooth at 30% then special at 65%. Gain 2 is thicker more deep, also staggeringly good at 30% and 65%, different but good. Very professional piece for lead guitar fanatics. I also used the Preamp/ clean channel as a boost for the Sans Amp PSA-1 distortion and it is the best, very full and balance, the best sound and tone I had been looking for in a long time.
Face melter metal and Rock full balanced lead tone. Pedal has a mid scoop that nails it perfectly for snap crackle and pop. Make sure to get a good tube amp and good effects rack. You won't be sorry.
Rated 5/5
Perfect for 80s rock and metal
I bought this thing for days i give my seven stringed guitar and my modern metal style a break and play some good ol hair band style on my six string, and does it do 80s PERFECTLY. I was able to get awesone def leppard like rockman tones as well george lynch like tones....truthfully, it can do any style. And this handles solos better than any other pedal or many amps i tried. Hooked straight into my peavey 6505 mh power amp section via effects loop return through a 2x12 and it sounds amazing, even hooked it to my old junk crate practice amp and it really polished that turd. I was even impressed with the clean preamp channelnas it handled my high output sd nazgul pickup without any breakup (my tube amp clean channels cant handle high pups).

My only minor gripe is that u can't change distortion and clean preamp channels fast as when u disengage either it goes in bypass, or it combines both channels when engaged(not sure why u would want to do that) so its a bit of a tap dance if u want to switch in between them
Rated 5/5
Hot Judas Priest Marshall Sound, from Defenders of The Faith!
If You're Familiar with Judas Priest' Legendary Metal Marshall Amp Tone from their "Defenders Of The Faith" album, "Some Heads are Gonna Roll", "The Sentinel", "Jawbreaker" "Love Bites", etc, for Me, with My Guitars, Humbucking Pickups, and Ears, I usually always end up adjusting the Theta Pedals Distortion and Active E.Q. into somehow Sounding almost Exactly Like, or Very Familiar to the Sound of a Hot Raging English Marshall, Heavy Metal Tube Amp Tone! Pretty Much Exactly Like the Hot Marshall EL34 Tube Heads Glenn Tipton and KK Downing had Used During Judas Priest' "Defenders Of The Faith" Recording Sessions.But that's just Me and my Ear and Gear, Your Experience may differ, Don't get me Wrong, this Thing Is Capable of Massive SLAYER "Seasons InThe Abyss/South Of Heaven" Type, Crazy Man Thrash Metal and Death Metal Tones as well as other Hot Marshall EL34 Tube, Lower Gain, ZZ TOP Billy Gibbons Type Marshall Sounds and Coolness as well!