Spirocore WEICH (Light) Red Mitchell 5ths Tuning Upright Bass Strings - Limited Quantity

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Multiple Sets & Single Strings Available
  • Spirocore Red Mitchell 5ths Tuning Upright Bass Strings, standard package
  • Spirocore Red Mitchell 5ths Tuning Upright Bass Strings, 4/4 specifications
  • Spirocore Red Mitchell 5ths Tuning Upright Bass Strings, 3/4 specifications
  • Spirocore Red Mitchell 5ths Tuning Upright Bass Strings, Thomastik comparison graph
Our Low Price: $274.95

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These strings have been discontinued by Thomastik-Infeld; once these are sold, they are no longer available. All strings are brand new and unused.


Spiros are an old favorite for jazz and other genres and has been a popular string for many years. They were one of the first decent metal strings to be adopted by strictly gut string players-- in fact, lots and lots of us played G & D guts and A & E Spirocores, since the larger gut strings of the mid-20th century still were too indefinite and flabby for good jazz articulation.

They have great sustain and a big sound good for many styles, but remain a jazz favorite. You'll also find them on lots of general use basses, for bluegrass, blues, and other styles where that big sound and sustain are prized. While they are certainly used by many fine arco players, they have a reputation for a scratchy sort of response under the bow -- and their stiffness requires an attention to proper technique. So if you bow a lot, and not strictly acoustically (scratchiness is particularly obvious when amplified), consider that reputation. I have used them sucessfully with magnetic pickups.

Includes our exclusive Gollihur Music tipsheet to get the most out of your purchaseThese strings are the "Red Mitchell" Signature set, which is a set for tuning in 5ths, which is favored by some players. They are tuned in a "cello" tuning - from low to high, the tuning is C-G-D-A.

Note about 3986 and 3985 sets:

The Spirocores are available in many different sizes and tensions. The most popular sets are the S42 variant; they are designed to be used on 3/4 and 4/4 size basses. If you have Spiros on your bass, chances are very good that they are the S42/S42W set. However, Thomastik also makes a 3/4 specific set, designated the 3885, which is very specifically sized and designed for optimal tension on a 3/4 size bass. For the Fifths Tuning sets, the (yes, confusing) numbering system is 3986=S42 (4/4 and 3/4) and 3985=3885 (3/4-specific).

Don't know which one to get? Get the 3986 variant -- they are, far and away, the most popular (and what you'll end up with if you buy from a store that doesn't specify). Only very particular players bother with the 3985, as the difference is quite minimal to most of us.

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1 Review

  • 5

    Posted by Ben Jaks on Mar 2nd 2023

    Tuning in fifths presents many challenges. The increased position changes is probably the most prominent issue but finding a set of strings that works for you and your bass is a big one too. I’ve tried the obligatos, they don't last long enough and they lack punch at the bottom end. I’ve tried mix and matching solo and orchestral strings with unfavorable results. I’ve tried the Red Mitchell reds and they were good but my bass seems to prefer a lighter string. The Red Mitchell weichs solved all these problems because they’re easy to play and the sound great. Simple as that. Being easy to play makes the position changes easier which makes intonation better thereby making the sound better. I play mostly arco and I have no problem getting a good bowed sound from them (just keep practicing)

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