Classic Jerry Garcia "Grateful Dead" Hi-Fi tones!


 Super Twin Stereo 88


  • Model No. STS88

  • Ultra Linear Stereo Tube Amp

  • 30 Watts Per Channel

  • Dynamic KT88 Power Output Tubes

  • 4-8-16 Speaker Impedance

  • Dual Channel Twin & Plexi Preamps

  • Separate Channel Volume & Tone Controls

  • Separate Channel 3 Band Tone Stacks

  • Separate Presence Controls With Edge Boost

  • Separate Effects Loops

  • Solid-State FRED Rectifiers

  • Post OT Line Out With Level Control

  • Tubes: 6 -12AX7, 4 - KT88

  • Custom Upgrade Options


MSRP: $1595.00

Sale Price:  $1196.25


The FRENZEL STS 88 "Super Twin Stereo 88"  is the stereo version of our classic Super Twin series of amps.  It was inspired by the Jerry Garcia's use of  Hi-Fi tube amps for the classic Grateful Dead sound. It is very unique and comes standard with  one channel voiced for the Fender Twin tones and one channel voiced for the Marshall Plexi tones plus many unique features including a separate volume, tone stack, and presence controls for each channel which allows you to fine tune the sound just the way you like it.   

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 High-Low separate input jacks for each channel. This allows you to match your pickup output impedance and to use an AB-Y switch select either channel or both to create your own unique tones! Each channel has separate voices, one F and one M and each with its own Gain Control with a Bright pull switch,  a 3 Band Tone Stack, Master Level Control and Presence control with Edge boost pull-switch that reduces 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!  

No matter how good any preamp is, it can always be fine tuned an Effects Loop to create your own unique tones with pedals. So we added  a passive buffer pure tube effects loop which matches low or high impedance pedals with the high impedance tube circuitry of the amp to eliminate tone suck and volume loss. 

Each output stage uses a pair of  KT88'S "the king of audio tubes" to give more headroom and warmth. For the output trannies we chose a ultra linear pro audio grade that provides you with extended low-end Fender 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. 

For the power supply section we used an over-sized 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  separate Gains, Tone Stacks, Masters & Presence controls.

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

  • Bright Pull Switch On Gain controls.

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

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

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

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

  • Line Outs - 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.

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

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

  • KT88  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 6 - 12AX7,  4 - KT88,  but you can substitute 12AT7's or 12AU7's in the preamp  for different tones and overdrive 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 Tubes - Class AB Push-Pull KT88's - Fixed Bias

  • Output Power - 30 watts RMS per channel

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

  • Line Out Impedance - 10K 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 chassis 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 High/Low Input Jacks, M High/Low Input Jack, F Gain with Bright Pull Switch, M Gain with Bright Pull Switch, Bass with Deep Pull Switch, Middle, Treble, Presence/Edge Boost Pull Switch, Standby Power Switch, Pilot Lamp, On/Off Power Switch

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

Upgrade Options:

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

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 



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