This is the second of two restored Heathkit SP-2 preamps that I had. The first one was sold last month. 
Classic vintage Heathkit SP-2 stereo vacuum tube preamplifier in excellent working condition. From 1958-1959. Fully re-capped. All capacitors were replaced with brand new high quality capacitors in January of 2026. Please see the last picture of all the old parts. All work was meticulously performed by my professional audio technician, Bruce, with almost 60 years of experience. Notice that he takes out the old capacitors by removing all the old soldering from their legs; he never cuts them off. He puts heat-shrink tubing on every new capacitor leg for safety and for best performance. 

All six tubes tested low (weak). They will need to be replaced in the near future. We noticed the left channel is slightly louder than the right channel. We swapped tubes. The imbalance is because of the unmatched and weak tubes. This preamp will really benefit from a fresh new set of matched tubes. This preamp was originally mounted in a console or in a large cabinet. It did not come with a top. We put rubber tips on the four bottom mounting screws (that would screw the chassis to a wood console). They are not feet. All inputs and outputs are located on the bottom of the chassis. When I found this preamp, the tube shields were missing. New tube shields are readily available here on eBay. Please familiarize yourself with the owner's (assembly) manual (free online). The SP-2 is a very early stereo preamp. It has features that are different than most more modern preamps. 

Over $400 were invested in parts and labor on this preamplifier. 
Work performed in late January, 2026:

1. All the old original capacitors (about 40) were replaced, including all the electrolytic, Mylar and ceramic disc capacitors ($250).  
2. The selenium rectifiers were replaced with modern diodes. This SP-2 now has a faster, cleaner and more linear response,        especially during wide dynamic musical passages.
3. A brand new, 21st century, heavy gauge, steel 3-prong, grounded 6-foot power cord was installed.
4. A brand new fuse assembly and a new fuse were installed. Originally, this unit wasn't fused. 
5. All five obsolete, outdated AC power outlets were removed. The auxiliary AC switch on the front panel for those was bypassed. An aluminum plate was installed to cover up the openings where the outlets were screwed in. 
6. All switches and controls (potentiometers) were cleaned twice with plenty of contact cleaner. 
7. All metal surfaces were cleaned and all the knobs were removed and individually washed.
8. Brand new power on/off indicator lamp. 
9. A perforated sheet metal cover was fabricated ($50 value; material and labor). 
10. The perforated metal sheet cover was professionally cleaned (chemical strip, outgas, media blast) and powder coated clear to prevent any rust in the future ($40 value). 

The sound quality is simply amazing. It sounds awesome! crystal clear, loud and very detailed, even with weak, unmatched tubes. No distortion. No hum. No noise (in my house with my audio system). All functions and all inputs were tested. I personally cleaned all controls and switches with electronic contact cleaner twice on 03/01/26. Please notice that most of the original lettering and markings on the face plate have faded or got erased over time. They are still visible, although not very clearly.  

Please do not expect this preamp to work like it did when it was new. It's almost 70 years old. It's a part of audio history. These Heathkits are cultural artifacts prized by collectors and vintage audio enthusiasts. They have flaws and are far from perfect. The knobs may not be as tight as when they were new and may not align perfectly. This preamp has many signs of age. It's still a little dirty inside. Please be aware that a tube may go bad at any time (they are already weak). In which case, the buyer would be responsible for replacing it. 

The photos are part of the description. Please look at them carefully. 

This preamp will be shipped with its knobs and tubes in place. Tube shields will be enclosed in the package. Upon delivery, please remove the SP-2 cover to verify the tubes are set in their sockets and to check that everything is OK. 

Please no returns. No buyer's remorse. No change of mind. No partial refunds. I like salvaging and restoring these amplifiers for someone to use and to enjoy. Thank you for your understanding.