| Dared Electronic ShenZhen | Tube Amplifiers |
| Official website M.V.S.Z AO Svetlana | Vacuum Tubes Manufacturers, Vacuum Tubes Retailers New Tubes |
| S.S. Stewart Tube Amp Users Group | Information |
| S-5 Electronics | Tube Amplifier Kits |
| SAC Thailand | Tube Amplifiers , Speakers, Tubes, Parts |
| Sage Audio | Retailer |
| Sajti | DIY Tube Amplifiers |
| Sakura Systems | DIY Tube Amplifiers |
| Salwender International | Tube Guitar Amplifiers |
| SAMS Technical Publishing | Books |
| SandMarc Audio | Tube Amplifiers |
| Sandokai | Audio Club |
| SAP | Tube Amplifiers, Speakers |
| Sascom Marketing Group | Studio Equipment |
| SatCure Audio | Tubes, Vintage Tube Audio Equipment |
| Savant Audio | Retailer for Tube Amplifiers |
| Schaltungsdienst Lange o.H.G. | Schaltpläne, schematics |
| schematicheaven.com | Schematics |
| Schuricht | Tubes, Parts |
| Schuro - Elektronik | Parts |
| Sci.Electronics.Repair FAQ | Tube Amplifier Services |
| ScientificDesign Ltd Pty | Lowther Club Australia |
| Scott-Nixon | Tube Kit DAC |
| Scruff & Audio Research | Museum |
| SD Sound | Tube Amplifiers |
| Seacor | Capacitors |
| Seamless Interface Electro Acoustiques | Tube Amplifiers |
| SECA-Consulting | Tube Amplifiers |
| Secondbeat | Online Hifi Magazine |
| Secrets of Home Cinema and HiFi | Audio Magazine |
| Seiden Products | Attenuators |
| Seigo Ito | Principles of Vacumm Tubes |
| Sekido Ryoichi's Audio Page | DIY Tube Amplifiers |
| Selco Products | Thermal Sensors, Panel Instruments, Knobs |
| Self Bias DIY Ultra-Fi Audio | DIY Tube Amplifiers |
| Semfielec | DIY Tube Amplifiers, Capacitors |
| Sempermusica | DIY Tube Amplifiers |
| Sennheiser | Headphone Tube Amplifier |
| Separo Audio | Tube Amplifiers |
| Sequerra | Tube Amplifiers |
| Serdi | Transformers |
| Serlui | Retailer |
| Servicesound | Tube Amplifier Service |
| ServoDrive, Inc | Speakers |
| Sescom | Parts, Transformers, Enclosures |
| SET Links | Links |
| Shallco | Attenuators & Potentiometers, Switches |
| Shenda Sound | Tube Amplifiers, Jolida |
| Shengya Audio | Tube Preamplifiers |
| Shenzen Shanling Electronic Co.,Ltd. | Tube CD-Player |
| Shenzhen Audcom Electronic Co. | Tube Amplifiers |
| Shimano-amp-212amp-e | DIY Tube Amplifier |
| Shindo Laboratory | Tube Amplifiers |
| Shino-Doraku | DIY Tube Amplifiers |
| Shinrock | Transformators, Capacitors, Tube Sockest |
| Shins Audio | Forums |
| Shorelineamps | Tube Amplifiers |
| Shortwave Transmitter Tubes | Tubes, Links, Tube Database |
| Shuffle Guitars | Tubes |
| Shuguang Electron Group Co.,Ltd. | Vacuum Tubes Manufacturer |
| Shun Mook Audio, Inc. | Tube Resonators |
| Sibatech | Distributor of Kondo and MCS Tube Amplifiers |
| Sicut Sol Editrice | Magazine, Audio Club |
| Siegmund's Guitars and Amplifiers | Tube Guitar Amplifiers |
| SIEL Sistemi Elettronici | FM Single Tube Amplifiers |
| Siemel | Tube Amplifiers |
| Sierra-Brooks Classic Horns | Horn Speakers |
| Sifakis 838 Amplifier | DIY Tube Amplifiers |
| Sigma Electroacoustics | Tube Amplifiers, Tube Headphone Amplifiers |
| Signal Transformer -- Industry-standard power transformers | Mains Transformers |
| Signature Sound | Retailer |
| Signature Technologies | Tube Amplifiers |
| Silbatone by Loth-X USA | Tube Amplifiers |
| Silsonic | Tube Amplifers |
| SilvaWeld | German distributor Tube Amplifiers |
| Silvaweld Audio Lab. | Tube Amplifers |
| Silverline Audio Technology Inc. | Speakers |
| Simpletube | Forums |
| Single Driver Website | Single Full Range Speaker Portal |
| Singlepower Audio | Tube Preamplifiers, Tube Headphone Amplifiers |
| SIS Audio | Tube Amplifiers |
| site Jeen | Private Tube Audio Sites |
| SiverTone Audio | Tube Amplifiers, Output Transformers SE |
| SixPacs | Tube Amplifiers |
| SJS Electroacoustics | Tube Amplifiers, Parts, Speakers |
| Skiff Home labs | Tube Guitar Amplifiers |
| Skip Simmons Amplifier Repair | Tube Amplifier Service |
| Skip's corner | 12AX7 Tubedata information |
| Skorpion - Tube Amps | Tube Amplifiers, Tube Headphone Amplifiers |
| SND Tube Sales | Tubes |
| Societe Quebecoise des Collectionneurs de Radios Anciens | Tube Radios & Related Vintage Items |
| Société Radio Tubes | Tubes |
| SoFlo Tubeamps | Vintage Tube Guitar Amplifiers |
| Soldano Custom Amplification | Tube Guitar Amplifiers |
| Solen | Capacitors, Speakers, Inductors |
| Soliloquy Bringing Life to Sound | Speakers |
| Son du Lac collection of DIY audiophile machines | DIY Tube Amplifiers |
| Songaudio | Tube Amplifiers |
| Sonic Craft | Speaker Kits |
| Sonic Soul | Parts, Transformers, Tubes |
| Sonique Audio | Tube Amplifiers, Speakers |
| Sonofield | Tube Amplifiers, Tube Amplifier Kits |
| Sonoran Publishing | Books |
| Sophia Electric | Tubes |
| Soriaudio | Forums, Links, Enclosures, Transformers |
| Sotis Audio | Tube Amplifiers |
| Sound As Clear As Light | Speakers |
| Sound Fusion | Speakers |
| Sound Performance Lab | Tube Vitalizer |
| Sound Practices | Tube Audio Magazine |
| Sound Technology plc | Retailer, Tubes |
| Sound.k.1 | Vintage Audio, Records |
| Soundberry | Retailer |
| Soundbox | Retailer |
| Soundelux Entertainment Group | Tube Microphones |
| Soundhaus Online-Shop -- Music-World | Links |
| Soundlabs Group | Retailer |
| Soundscape | Audio + Video + Art, HIFI, Stereo, Audio |
| Soundsgreatmusic | Club |
| Soundsmith, Inc. | Tube Amplifier, Repair and Modifications |
| SoundStage! | Audio Magazine |
| SoundStage! John Upton - Tu-be or Not Tu-be | Articles |
| Southern Electric Audio | Retailer, Articles, Altec Ecperimenter Info |
| Sovtek | Tubes, Parts, Tube Guitar Amplifiers |
| Sowter Audio Transformers | Transformers, Attenuators |
| Soynia Electronics | Parts |
| SP Technology Loudspeakers | Speakers |
| Space-Tech Hi-End tube audio Laboratory | Tube Amplifiers |
| Spark | Tube Amplifiers |
| Sparkgap | DIY Tube Amplifier |
| Speaker | Speakers |
| Speaker Hifi | Speaker |
| Speakers Delight | Speakers, Retailer |
| Speakers for fun | DIY Tube Amplifiers |
| Speakerworld | DIY Speaker site, information, links, forum |
| SPECIAL PURPOSE TO JAN TUBE TYPE CROSS REFERENCE | Tube Database |
| Specimen | Custom Tube Guitar Amplifiers |
| SpectrumAudio | Full Range Speakers and more |
| Speedster Amplifiers | Tube Guitar Amplifiers |
| Speedster Amplifiers | Tube Guitar Amplifiers |
| Spendor Audio Systems | Speakers |
| Sphere Research Corporation | Tubes |
| Spieker Audio Engineering | DIY Tube Amplifiers |
| Staffall | Standoffs |
| Stan Nelson's Antique Radios | Tube Radios & Related Vintage Items |
| Stan White Audio | Speakers |
| Star Sound Technologies | Cones |
| Stark Electronic | Tubes |
| Stax Earspeakers | Tube Amplified Electrostatic Headphones |
| Steinmusic | Parts, Tubes |
| Stereo Exchange | Tube Amplifier Service |
| Stereo Online | German Audio Magazine |
| Stereo Repair | Tube Amplifier Service |
| Stereo Servic | Tube Amplifier Service |
| StereoManuals.com | Manuals |
| Stereophile | Audio Magazine |
| Stereophone | Classifieds, Tube Amplifier Service |
| Stereophonic Audio--A History | A little Audio History |
| Stereoplay | German Audio Magazine |
| Steve Hoffman | Forum, Music |
| Stevens & Billington Ltd Audio Transformers | Interstage Transformers |
| Steve's Tube Pages | DIY Tube Audio, Schematics |
| STF-Electronics | Tubes, Transformers, Tube Amplifier Kit |
| Stoneaudio UK | Sonic Link 211SE Tube Amplifier |
| Strassacker Lautsprecher - Boxen - Selbstbau | Speakers |
| Straub | Links |
| Strona domowa Macka Parvi | Links, Information |
| Stubbyfex Electro-Mechanical Repair | Tube Amplifier Service |
| Studio K | Private Tube Audio Sites |
| Studio M | Retailer, Capacitors, Transformers, Resistors, Speakers, Articles |
| Subas Audio Marketing | Retailer |
| Sugimoto | DIY Tube Amplifiers |
| Sultone Amp Cabinets | Cabinets & Hardware |
| Summit Audio | Professional Tube Electronics |
| Sun Audio | Tube Amplifiers |
| Sun Valley | Tube Amplifiers, Speakers |
| Sunfire Corporation | Tube Preamplifiers |
| Suntan Capacitors Company | Capacitors |
| Suomen Radiohistoriallinen seura | Tube Radios & Related Vintage Items, Associations |
| Suono | Magazine |
| Super Triode Connection | DIY Tube Amplifiers |
| SuperAmps | Tube Amplifiers |
| Super-OTL-Audio | DIY Tube Amplifier |
| Supersonic Comm. | Tube Microphones, Repair, Service |
| SuperTNT.com-Get Chinese Vacuum Tubes Directly | Tubes |
| Supratek Triode | Tube Amplifiers |
| Supravox | Distributor of Supravox |
| Supravox | Fullrange Speakers |
| Surplus Electronic | Tubes, Tube Radios |
| Surplus Electronic Test Equipment Eltech | Tubes |
| Surplus Sales of Nebraska | Vintage Tube Audio Equipment, Tubes |
| Surplus Sales of Nebraska Index | Parts, Tubes |
| Svetlana Tubes | Vacuum Tubes Manufacturers |
| Svetlana Tubes @ www.ezboard.com | Svetlana Tubes Message Board |
| Svetlana USA! | Tubes |
| Swan & Vintage Radio Tubes | Information |
| Swart Amplifier Co | Tube Guitar Amplifiers |
| Swedish Radiotube Shop | Tube Radios & Related Vintage Items |
| SWR Sound Corporation | Professional Tube Electronics |
| Synthesis | Tube Amplifiers |