Super Twin 800


Model No. ST-800
Series: Super Guitar Head 

MSRP: $1325.00     

Sale Price - $995.00   


The FRENZEL STP 50/100 "Super Twin 800"  was designed as the ultimate amp for the serious player.  It  has a lot of soul that is generated by two separately voiced preamps each with its own separate Gain control, 3 band tone stack,  and Master level control. One preamp is voiced like the classic Fender 5F8A Twin…the other the Marshall JCM800. This amp is a unique one of a kind designed totally for the creative player in mind. It will give you just about any sound you ever dreamed of.  

The heart of any amp is the preamp…it generates the signature tones. The preamp in this amp is a killer tone machine like none you have ever heard. It has separate input jacks for each channel. This allows you to use an AB-Y switch select either channel or both to create your own unique tones! Each channel has separate F and M preamps each with its own Gain Control,  3 Band Tone Stack, and Master Level Control.   Both preamps share the same Presence control which is part of the output circuitry. Also, we have put an Edge pull-switch on the Presence control that sets the negative feedback level to produce a boost in volume and a soaring uncompressed sound for dynamic leads. The combination of all these options generates a wide ranges of tones from Clapton warm to Van Halen hot!  

We left the output stage design of the amp pretty much undisturbed from the vintage design except  we replaced  the 5881’s  used in the Twin with the new higher plate voltage JJ 6L6GC'S to give more headroom and warmth. For the output trannie we chose a vintage Marshall for the original classic vintage sound. This trannie provides you with extended low-end warmth and those  incredible enhanced Marshall overtones. All the while, maintaining a perfect balance between the highs, mids, and lows. The trannie  has  4, 8, and 16 ohm output taps which are selectable by a switch on the back of the amp. Two speaker jacks are provided for multiple speaker cabs.  

For the power supply section we used an oversized custom power transformer. which provides great voltage regulation so that you don’t sag too much when you get on it hard. The high-voltage is filtered for very low hum by an equally large choke and 8 filter capacitors.  We stayed with the Marshall choice of solid state rectifiers, but chose the newest type FRED ultra fast recovery rectifiers for tight dynamic bass response. 

The amp is built on a compact 17” x  10”  x 3” aluminum chassis and come with a retro steel mesh cage. All the parts in the amp are top-of-the line  including polypropylene coupling caps, precision mica tone stack caps, metal film resistors, Alpha pots, Neutrik jacks, high voltage sockets, etc…  This is a rock solid point-to-point hand wired amp….a real one of kind collectors item...designed to last for generations! 


Standard Features:

  • Dual Channel - Each channel has High/Low input jacks, separate Gains, Tone Stacks & Masters.

  • Channel 1  - Fender Twin smooth  warm clean tones.  Channel 2 - Marshall JCM800 high overdrive  tones....or you can use an AB-Y switch and create your own distinct tones.

  • Classic Bassman 5F6A style 3-BAND TONE STACK for extended flexibility in shaping your tone.

  • Master level control so you can crank the GAIN's up and overdrive the preamp without overdriving the output tubes.

  • Presence control  - used to adjust the high-frequency response and damping factor of the power amp section.

  • Boost - Unique NNFB "Edge" boost switch on the PRESENCE control that transforms the power amp section into a No-Negative-FeedBack style amp for soaring dynamic leads. 

  • Effects Loop - pure tube buffered serial effects loop designed to perfectly match the low impedance solid-state pedal levels with high impedance tube levels.

  • Line Out - post output transformer LINE OUT with LINE OUT LEVEL control for recording or driving a power amp, Auto switched internal load to simulate speaker if speaker is  not plugged in. Inject great tone directly into the PA system with the Speaker Simulated Direct Interface.

  • Custom heavy duty output transformer for extended low frequency performance with 4 - 8 - 16 ohm outputs selectable by a rotary switch.

  • EL34/6L6 Bias Selector Switch - Allows you to use either 6L6 or EL34 power output tubes.

  • Solid-State FRED ultra fast recovery rectifiers for tight dynamic bass response.

  • Standby Switch - Protects tubes from cathode stripping during warm-up

  • Tube Complement: comes standard with 3 - 12AX7, 1 -12AU7, 2 - 6L6, 1 - 5AR4, but you can substitute 12AT7's or 12AU7's in the preamp and driver for different tones and overdrive sounds. You can also substitute 5881's, KT66's, KT88's, 6550's, or EL34's and KT77's when using the EL34/6L6 Bias Selector Switch  in the output stage for different sounds. 


Electrical Specifications: 

  • Input Power  120 VAC 50-60Hz - 225 Watts Standard IEC plug-in three prong grounded power cord. (100VAC & 240VAC available. See Upgrade Options) 

  • Output Power - 50 watts RMS (100 Watt Quad of 6L6's upgrade also available. See Upgrade Options) 

  • Output Power Selector Switch - provides three power levels. 1/4 - 1/2 - FULL power. 

  • Speaker Output Impedance - selectable by switch 4-8-16 ohms.

  • Line Out Impedance - 10K ohms

  • Effects Loop Send Impedance - 10K ohms

  • Effects Loop Return Impedance -  470K ohms

  • Instrument Input Impedance - 1 Megohm

  • DC on filaments to eliminate 60 hz hum.

  • Star ground system to eliminate induced current chassis noise.

Physical Data: 

  • Chassis Dimensions - 17" Wide x 10" Deep x 2" High. ( Allow 6" Above chasis for tube clearance)

  • Weight - 23 lbs. 

  • Chassis - Heavy gauge aluminum with welded corners.

  • Retro Vintage Cage Head  - heavy duty lightweight steel mesh cage provides protection and excellent ventilation for tubes. Comes with easy carry Fender style strap handle. Overall  Dimensions - 17" Wide x 12" Deep x 10" High (Includes feet, handle and knobs)

  • Rock solid point-to-point hand wiring with military style tie-wrapped wiring harnesses for long life and reliability.

  • Input and Output Jacks isolated from chassis for low noise, eddy currents, and hum.

  • Components:  Only the highest quality parts are used including heavy duty transformers, low noise tubular polypropylenes capacitors, metal film resistors, Micalex sockets, Neutrik jacks. All parts are rated for commercial high use conditions. Wherever possible we use parts made in the USA.

  • Front Panel:  F Input Jack, M Input Jack, F Gain, M Gain, Bass, Middle, Treble, Presence/Edge Boost Switch, Standby Power Switch, Pilot Lamp, On/Off Power Switch

  • Rear Panel:   Power Cord Connector, Fuse,  Effects Loop Return Jack, Effects Loop Send Jack, Output Power Level Switch, Line Out Level, Line Out Jack, Speaker Output Jack, Speaker 4-8-16 Impedance Selector Switch.

Upgrade Options:

These options allow you to  customize your amp to meet your special individual requirements.

100 WATT QUAD 6L6'S -   Increases power output to 100 watts.   Add $200.00.

240 VOLT POWER TRANSFORMER - for operation outside the USA  where 240VAC line voltage is used. Add $55.00

100 VOLT POWER TRANSFORMER - for operation outside the USA  where 100 VAC line voltage is used. Add $55.00 


Hi Jim, - As many of your other customers' reviews on your site, I would like to let you know how great I think your amp is, now that I've had it for a while... I'm using the amp for just about any situation from folk, country,  jazz, to harder driving stuff, and it takes crazy effects well too...I run both dry(only) and wet(only) signals out of my delay into both channels, and the tone is VERY rich... running through a 2x12 w/ a JBL D-120, and a EVM12L produces amazing clarity and precision to my ear - while either of the speakers in a 1x12 show off what the amp can do... I am very happy that I went through with the purchase after a few years of hesitation... everything written about the amp in the description on your website is what I received, and it sounds better than I imagined...Thank you very much, for the amp, and your fabulous service... I must have another soon...Charlie H. (CANADA)
Jim  - Hello, I just bought a used Frenzel Super Twin amp head. It is a fantastic amp!  Brian R. (Oregon) 

Hi, It's been a year since I purchase my custom Frenzel Super Twin 800 and  I have to say that I'm in love with your Marshall channel. I like it a lot for playing break-up strat sounds.  Gerardo Regalini (Brazil) 

For more reviews please check our  REVIEWS page.