TS7 Tube Screamer Modification Blindfold Tests

I decided to conduct a web-based blindfold test to study the changes in sound produced by some of the more popular modifications of the Ibanez Tube Screamer distortion pedal for guitar. I performed the mods on my TS7 Tube Screamer pedal and made recordings, being careful to keep everything in the test setup the same except the pedal circuit modifications.

The Test Sample

I recorded myself playing the guitar into a Boss RC-20 Loop Station pedal. The guitar was my 1977 Ibanez "Lawsuit" Les Paul, using the bridge pickup, which is a DiMarzio X2N. This recording was played out of the RC-20 into the Tube Screamer for the entire series of tests. I used exactly the same recording for every test in an effort to eliminate variations in guitar playing that might be perceived as differences in the sound of the Tube Screamer pedal between recordings.

The test sample was divided into 8 sections:

  1. Section 1: Blues Chords
  2. Section 2: Long Power Chord
  3. Section 3: Short Power Chord
  4. Section 4: Lead With Dynamics
  5. Section 5: Long Single Note
  6. Section 6: Short Single Note
  7. Section 7: Long Fourth
  8. Section 8: Short Fourth

Here is the dry sample of all 8 sections playing directly into the computer: (6.4MB WAV)

The Test Rigs

Test Rig 1 (direct)

Test Rig 2 (through H&K Tubeman)

The Tests

In each test, the 8 sections of the recording have been separated so that a unique test can be performed on each section. Each page has an email link at the bottom which the listener can use to send his/her answers to me for counting. At some point I will post the results on the page.

Click a link below to take a test!

I. Op-amp Type

A. JRC4558 vs. LM1458

B. JRC4558 vs. TA75558

II. Output Resistor Mod ("808 Mod")

A. With Test Rig 1 (direct)

B. With Test Rig 2 (through H&K Tubeman)

III. Carbon Composition Resistor Mod