Fender Studio Bass Club!

[chriswell]

I recently refurbished this bass amplifier and am thoroughly impressed by its performance. Its sound remains remarkably transparent even at frequencies as low as 20 or 30 Hz. The inductance EQ stands out for its unique characteristics. The standard Treble, Bass, and Mid knobs (passive) respond quite differently due to the inductance EQ circuit. In my experience, this EQ behaves unlike any other I have used—producing a distinctly musical effect. I am curious to know if others have observed similar qualities. The inductance EQ technology was primarily used during a transitional period in the late 1970s, before active EQ became standard in amplifiers. From what I have read, the high cost prevented manufacturers from incorporating it into their regular product lines. I welcome any additional insights or experiences regarding this feature.

 

[Patrice B]

I recently refurbished this bass amplifier and am thoroughly impressed by its performance. Its sound remains remarkably transparent even at frequencies as low as 20 or 30 Hz. The inductance EQ stands out for its unique characteristics. The standard Treble, Bass, and Mid knobs (passive) respond quite differently due to the inductance EQ circuit. In my experience, this EQ behaves unlike any other I have used—producing a distinctly musical effect. I am curious to know if others have observed similar qualities. The inductance EQ technology was primarily used during a transitional period in the late 1970s, before active EQ became standard in amplifiers. From what I have read, the high cost prevented manufacturers from incorporating it into their regular product lines. I welcome any additional insights or experiences regarding this feature.

That EQ design is really a plus on Studio Bass/Supertwin! Add to this the boost/distortion and it covers a lot of tonal colours! I’ve made the mod to the distortion circuit found elsewhere on this site BTW.

A real pleasure with my Rick 2003SW and an homemade 2x10!

 

[murphy]

I recently refurbished this bass amplifier and am thoroughly impressed by its performance. Its sound remains remarkably transparent even at frequencies as low as 20 or 30 Hz. The inductance EQ stands out for its unique characteristics. The standard Treble, Bass, and Mid knobs (passive) respond quite differently due to the inductance EQ circuit. In my experience, this EQ behaves unlike any other I have used—producing a distinctly musical effect. I am curious to know if others have observed similar qualities. The inductance EQ technology was primarily used during a transitional period in the late 1970s, before active EQ became standard in amplifiers. From what I have read, the high cost prevented manufacturers from incorporating it into their regular product lines. I welcome any additional insights or experiences regarding this feature.

That EQ design is really a plus on Studio Bass/Supertwin! Add to this the boost/distortion and it covers a lot of tonal colours! I’ve made the mod to the distortion circuit found elsewhere on this site BTW.

A real pleasure with my Rick 2003SW and an homemade 2x10!

Love the cases you have...especially the natural wood.
Skills for sure

 

[rodl2005]

That EQ design is really a plus on Studio Bass/Supertwin! Add to this the boost/distortion and it covers a lot of tonal colours! I’ve made the mod to the distortion circuit found elsewhere on this site BTW.

A real pleasure with my Rick 2003SW and an homemade 2x10!

What does the mod do?

 

[Patrice B]

What does the mod do?

Makes the distortion tolerable…

Quote:

«

Distortion​

Apparently, Fender tried to fix the original crappy channel with another crappy one.
On the cathode of V3, after the 4.7K cathode resistor, they changed the circuit from just a 3.3K resistor to a 2.2K R paralleled by a diode into a coil (marked 01194 4 on the scheme). I changed the 2.2K resistor to a 1 meg ohm. It changed the whole channel for the better. It is not a heavy metal Fender Studio Bass Club Wiki Page, kind of a soft Distortion. [Source] »

Right from the wiki here: Fender Studio Bass Club Wiki Page

 

[Patrice B]

Love the cases you have...especially the natural wood.
Skills for sure

DIY case with spruce! Thanks!

 

[Patrice B]

DIY case with spruce! Thanks!

Oh well, pine… not spruce!

 

[Pontiac Thrasher]

Oh well, pine… not spruce!

Good enuff : )

Makes the distortion tolerable…

Quote:

«

Distortion​

Apparently, Fender tried to fix the original crappy channel with another crappy one.
On the cathode of V3, after the 4.7K cathode resistor, they changed the circuit from just a 3.3K resistor to a 2.2K R paralleled by a diode into a coil (marked 01194 4 on the scheme). I changed the 2.2K resistor to a 1 meg ohm. It changed the whole channel for the better. It is not a heavy metal Fender Studio Bass Club Wiki Page, kind of a soft Distortion. [Source] »

Right from the wiki here: Fender Studio Bass Club Wiki Page

I have thought for years (since about 1979) that someone could design a mod for that works well. Do you think the distortion could still be improved beyond the mod that you have done? If so what attributes would change?

Regards,

 

[Patrice B]

Good enuff : )

I have thought for years (since about 1979) that someone could design a mod for that works well. Do you think the distortion could still be improved beyond the mod that you have done? If so what attributes would change?

Regards,

Sorry, I am the kind of « paint by number » guy . To resume, I don’t understand the theory at all except basic concepts so I can’t help.

Someone like @Wasnex or @beans-on-toast maybe would be more knowledgeable?

***Looked at the « source », just in case but forum is dead… Wayback machine to the rescue… but only one post!

 

[Pontiac Thrasher]

Sorry, I am the kind of « paint by number » guy . To resume, I don’t understand the theory at all except basic concepts so I can’t help.

Someone like @Wasnex or @beans-on-toast maybe would be more knowledgeable?

***Looked at the « source », just in case but forum is dead… Wayback machine to the rescue… but only one post!

View attachment 7446907

Thank you!

It seems like it could be engineered into a effects in/out so we could stash whatever pedals we want hidded in the head cab and thereby use the factiry switching for our "distortion."

But not engineered by you and I : )

 

[beans-on-toast]

Sorry, I am the kind of « paint by number » guy . To resume, I don’t understand the theory at all except basic concepts so I can’t help.

Someone like @Wasnex or @beans-on-toast maybe would be more knowledgeable?

***Looked at the « source », just in case but forum is dead… Wayback machine to the rescue… but only one post!

View attachment 7446907

Fender CBS did some boneheaded things that didn’t sound so good. I would remove the distortion circuit and make it like a standard twin reverb. If distortion is needed, use a pedal.

 

[Patrice B]

Fender CBS did some boneheaded things that didn’t sound so good. I would remove the distortion circuit and make it like a standard twin reverb. If distortion is needed, use a pedal.

For me, and I am not at all a distortion guy, neither for bass or electric geetar, it doesn’t sound that bad once modded… but I wouldn’t trust me .

Mind you, I like fuzz but it’s not the same!

 

[Pontiac Thrasher]

Fender CBS did some boneheaded things that didn’t sound so good. I would remove the distortion circuit and make it like a standard twin reverb. If distortion is needed, use a pedal.

A factory pedal switch and switching circuit is a terrible thing to waste.

: )

 

[Patrice B]

At around the 4:10 mark, this chap put distortion at about 6. Unmodded circuit I guess.

Sound is bleh … but what do I know

 

[Patrice B]

Opinions on the distortion ckt as is!

Invalid Link Removed

 

[beans-on-toast]

A factory pedal switch and switching circuit is a terrible thing to waste.

: )

I’ve read that the distortion knob shifts a tube’s operating point into a non-linear region. This should add compression initially and eventually distortion by clipping the signal waveform. But it really depends on how hard the amp is being driven. There might be a balance where it sounds good when just cracked open a bit. If you leave the distortion off, the amp should operate cleanly.

Experiment to dial in a good setting.

 

[Patrice B]

I’ve read that the distortion knob shifts a tube’s operating point into a non-linear region. This should add compression initially and eventually distortion by clipping the signal waveform. But it really depends on how hard the amp is being driven. There might be a balance where it sounds good when just cracked open a bit. If you leave the distortion off, the amp should operate cleanly.

Experiment to dial in a good setting.

What I read is that they wanted « distortion » to compete with other brands. However, for the designer, distortion was… distortion. Maybe not the good one?

Thanks God, this amp is mostly despised by guitar player so more for us, cheaper! There was one at 600 CAD in the classifieds… but I don’t need two!

 

[Wasnex]

I am not generally a mod guy. Not totally opposed if a mod is necessary for a usable tone, but I don't have the chops necessary to devise my own mods.

The chances of a mod being worth the squeeze in this instance may be fairly low. Amps tend to have a characteristic way of distorting, which you either like and find ususable or don't. Same goes with pedals. But with pedals you might use one pedal for a certain sound and then use a different pedal for a different sounds. My pedal board has 5 or 6 drive pedals on it. Most people probably wouldn't switch amps to get different drive sounds.


I do have a handful of guitar amps. I purposefully bought the classics, so I get the characteristic drive they are known for.

 

[Wasnex]

I’ve read that the distortion knob shifts a tube’s operating point into a non-linear region.

Not sure if that is quite right. Here's my circuit analysis...but keep in mind my electronics knowledge is pretty basic, so I may be wrong. Let me know what you think.

See schematic of circuit below.

AFAIK, the tube section (V3A) has two operating points. The cathode circuit is fed -30V when distortion is off and -11V when distortion is on. AFAIK none of the pots have an impact on the tube operating point.

Looks like the signal is taken off a pot connected between the cathode and control grid of V3A. I assume this pot allows you to blend the clean signal present at the control grid with the distorted signal at the cathode.

The signal from the distortion (blend) pot is fed through a capacitor to another pot that sets the level.

 

[Pontiac Thrasher]

What I read is that they wanted « distortion » to compete with other brands. However, for the designer, distortion was… distortion. Maybe not the good one?

Thanks God, this amp is mostly despised by guitar player so more for us, cheaper! There was one at 600 CAD in the classifieds… but I don’t need two!

I think they were trying to offer a low volume distortion alternative to the amps natural distortion when ran, in those days, cranked, into, for example, my favorite, a pair of 15" JBL E130-8's in a 65 Dual Showman kick back cabinet, using a Stratocaster : )

Awe inspiring, if you have the ears for it, I love it!