FAQ

How do I know if a tube has gone bad?

The tube should light up when the amplifier is turned on. If the tube has a white substance coating on the inside at the top of the tube, then it has lost its vacuum and should be replaced

My combo amp vibrates on certain notes. Why? What is that sound?

Chassis screws can loosen over time. Check to make sure all screws are tight. Tubes can also develop rattle over time due to heat and mechanical wear and tear.

I am getting unwanted distortion when using the FX loop on my Blues King or Keeley amp.

The effects loop in the Blues King 12 and Keeley amplifiers is a passive design that does not pad or limit the amount of voltage present at the SEND jack. This approach retains 100% of the tube tone of the amp when the loop is not in use. Due to the large signal coming from the preamp, distortion can occur when the preamp volume is turned up to the point where it is outputting a signal larger than the effect is capable of handling.

What fuse do I need for my Amplifier?

Supro amps wired for 120V require a 3A fast blow fuse. Supro amps wired for 240V require a 1.5A fast blow fuse.

Where can I get my Supro amp serviced?

Contact your local electronics repair technician for tube amplifier service.

Where is the fuse in my amp located?

The fuse is located inside the IEC receptical.

How can I safely use an extension cabinet?

Supro combos come with an 8-ohm speaker installed. Use an 8-ohm extension cabinet to achieve a 4-ohm overall load. Certain Supro models switch impedance automatically, while others require the user to manually swap the internal speaker over to the 4-ohm output jack. Check your amp’s user manual for reference.

Where are Supro amps made?

Supro Blues King amplifiers are made in China. All other Supro tube amp models made between January of 2014 and July of 2020 were assembled in Port Jefferson, NY USA.

What is the difference between the original Saturn and Saturn Mk II?

The original Saturn had a 5U4 tube rectifier, DT12 speaker and 6973 power tubes. The Saturn Mk II has a solid state rectifier, a BD12 speaker and 6V6 power tubes.

What is the difference between the original Thunderbolt, Thunderbolt + and Thunderbolt Mk II?

The original Thunderbolt came with a 5U4 tube rectifier and was hardwired at 35W Class A. The Thunderbolt+ came with the addition of a 3-way switch to select 35W class a (tube rectifier), 45W Class A (solid-state rectifier), 60W Class AB (solid-state rectifier). The Thunderbolt Mk II has a 2-way switch to select 35W Class A or 60W Class AB, both with solid-state rectifier.

Can I put a tube recitifier in the open slot on my amp?

No. If your amp did not come with a tube rectifier, then that open socket is not wired up.

Why was an amp discontinued?

The Supro product line has continued to evolve since the brand was initially reissued in 2014.

Can I upgrade my amp to the Mk II version?

Yes. This work can be performed by an authorized Supro service technician.

About effects loop impedance

Supro amps use a high-impedance SEND and low-impedance RETURN.

Can I add an extension speaker jack?

We do not recommend any electrical modifications to Supro tube amps.

Can I add an effects loop?

We do not recommend any electrical modifications to Supro tube amps.

Can I substitute tubes? 6V6 for 6L6 KT66 etc?

We recommend using factory specified tube types only.

Can I swap preamp tubes?

We recommend using factory specified tube types only?

Variation on tubes 6L6WGC vs 5881 designation

Supro amplifiers are specifically designed to be used with factory specified tubes. We do not recommend using alternate tube types in Supro amps. Check your amp’s user manual for reference.

I have a Zinky made supro, can you fix it?

Contact Bruce Zinky at: zinkyamps.com

Is Bruce Zinky still involved with Supro?

Bruce Zinky is not officially involved with Supro at this time.

Can you repair my vintage Supro amp?

Contact your local electronics repair technician for tube amplifier service.

Are Supro guitars discontinued?

Supro guitars are not in production at this time. They will return. 

To view specs on discontinued models, please visit our Legacy Products section. Please email info@suprousa.com for any additional questions about Supro Guitars.

How do I stop my pedal from automatically turning on when powering up?

Hold the footswitch down when powering up to change the default status to OFF when powering up. You only need to do this one time. Perform the same action to switch the default status back to ON.

About expression pedal specs

Supro pedals accept industry-standard expression pedals with TRS wiring. An Impedance rating somewhere between 10K – 100K is ideal.

About power supply voltages and sonic implications

The Supro Delay can only run on 9VDC. Higher voltages will damage the pedal. All other Supro pedals can run on power supplies ranging from 9V – 18V. More voltage will increase both headroom and output level.

Do I need a buffer with Supro fuzz?

The Supro Fuzz does not require a buffer.

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