| TS7 Blindfold Tests /\ | ||
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Check out my YouTube channel. |
The prevailing wisdom is that using carbon composition resistors in the audio path instead of the more common carbon film type will produce a "warmer" sound. I replaced three of the stock 1K resistors in the audio path of the TS7 with carbon composition resistors of similar value:
Here are the resistor locations shown on the TS7 schematic:
| R1 | R30 | R49 |
|---|---|---|
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And here they are as shown on the general Tube Screamer Schematic from the Tube Screamer Technology Page:
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Here is what the board looked like before and after the modification:
| Before | After |
|---|---|
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TS7 with the JRC4558 op-amp and the output resistor mod. |
TS7 with the JRC4558 op-amp, the output resistor mod, AND R1, R30, and R49 changed to carbon composition resistors. |
Here are the measured values of the resistors before and after the modification:
| Designator | Stock value |
Carbon Composition Replacement Value |
|---|---|---|
| R1 | 988 ohms | 991 ohms |
| R30 | 992 ohms | 992 ohms |
| R49 | 987 ohms | 986 ohms |
In each section below, one of the recordings was done with the output resistor mod only, and the other was done with the both the output resistor mod and the carbon composition resistor mod. They have been mixed randomly. Select the recording you think has the carbon composition resistors.
| Section 1: Blues Riff | Recording A (2765K wav) | Recording B (2754K wav) |
| Section 2: Long Power Chord | Recording A (1797K wav) | Recording B (1904K wav) |
| Section 3: Short Power Chord | Recording A (208K wav) | Recording B (231K wav) |
| Section 4: Lead with Dynamics | Recording A (2903K wav) | Recording B (2882K wav) |
| Section 5: Long Single Note | Recording A (1064K wav) | Recording B (954K wav) |
| Section 6: Short Single Note | Recording A (179K wav) | Recording B (172K wav) |
| Section 7: Long Fourth | Recording A (1015K wav) | Recording B (1325K wav) |
| Section 8: Short Fourth | Recording A (182K wav) | Recording B (134K wav) |
The average score so far is 3/8 correct. I certainly can't hear any difference in the recordings, so I'm inclined to think that these resistor changes are having no effect. But someone could prove me wrong...
