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Audio Tube

Saturday, August 6th, 2011
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NOS GOLD PIN INPUT DRIVER OUTPUT TRANSFORMER FOR AUDIO PRE TUBE AMPLIFIER NOS GOLD PIN  INPUT DRIVER OUTPUT TRANSFORMER FOR AUDIO PRE TUBE AMPLIFIER

VINTAGE DUMONT 6EA7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO VINTAGE DUMONT 6EA7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO

VINTAGE DUMONT 6GF7A NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO VINTAGE DUMONT 6GF7A NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO

VINTAGE CONRAC 6BX7GT NOS VACUUM TUBE TESTED STRONG AUDIO RADIO AMPLIFIER VINTAGE CONRAC 6BX7GT NOS VACUUM TUBE TESTED STRONG AUDIO RADIO AMPLIFIER

1 VINTAGE GE 25Z6GT NOS VACUUM TUBE TESTED STRONG AUDIO RADIO AMP 1 VINTAGE GE 25Z6GT NOS VACUUM TUBE TESTED STRONG AUDIO RADIO AMP

1 VINTAGE SYLVANIA 6SL7GT NOS VACUUM TUBE TESTED STRONG AUDIO RADIO AMP 1 VINTAGE SYLVANIA 6SL7GT NOS VACUUM TUBE TESTED STRONG AUDIO RADIO AMP

1 VINTAGE SYLVANIA 6Q7 NOS VACUUM TUBES TESTED STRONG AUDIO RADIO AMPLIFIER 1 VINTAGE SYLVANIA 6Q7 NOS VACUUM TUBES TESTED STRONG AUDIO RADIO AMPLIFIER

1 VINTAGE RCA 6AX5GT VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMPLIFIER 1 VINTAGE RCA 6AX5GT VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMPLIFIER

1 VINTAGE PHILCO 6AX4GT NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMPLIFIER 1 VINTAGE PHILCO 6AX4GT NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMPLIFIER

1 VINTAGE PREMIUM QUALITY 6S4 VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP 1 VINTAGE PREMIUM QUALITY 6S4 VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP

VINTAGE RCA 5963 12AU7 NOS VACUUM TUBE TESTED AUDIO RADIO AMPLIFIER VINTAGE RCA 5963 12AU7 NOS VACUUM TUBE TESTED AUDIO RADIO AMPLIFIER

1 VINTAGE RCA 6S4A NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP 1 VINTAGE RCA 6S4A NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP

1 VINTAGE RCA 12AU7A ECC83 NOS VACUUM TUBE TESTED STRONG AUDIO RADIO 1 VINTAGE RCA 12AU7A ECC83 NOS VACUUM TUBE TESTED STRONG AUDIO RADIO

1 VINTAGE RAYTHEON 12AU7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP 1 VINTAGE RAYTHEON 12AU7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP

SYLVANIA 12AU7 NOS Vacuum Tube Tested Strong AUDIO HAM RADIO AMPLIFIER SYLVANIA 12AU7 NOS Vacuum Tube Tested Strong AUDIO HAM RADIO AMPLIFIER

1 VINTAGE SYLVANIA 12AV7 VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP 1 VINTAGE SYLVANIA 12AV7 VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP

VINTAGE RCA 12BV7 NOS VACUUM TUBE TESTED STRONG AUDIO RADIO VINTAGE RCA 12BV7 NOS VACUUM TUBE TESTED STRONG AUDIO RADIO

1 VINTAGE RCA 12BY7A NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP 1 VINTAGE RCA 12BY7A NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP

1 VINTAGE RCA 6X4 EZ90 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMPLIFIER 1 VINTAGE RCA 6X4 EZ90 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMPLIFIER

VINTAGE RCA 12BR7 NOS VACUUM TUBE TESTED STRONG AUDIO RADIO VINTAGE RCA 12BR7 NOS VACUUM TUBE TESTED STRONG AUDIO RADIO

1 VINTAGE SYLVANIA 6JU8 VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP 1 VINTAGE SYLVANIA 6JU8 VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP

1 VINTAGE SYLVANIA 12AV7 VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP 1 VINTAGE SYLVANIA 12AV7 VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP

1 VINTAGE PHILCO 12BH7A NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP 1 VINTAGE PHILCO 12BH7A NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP

1 VINTAGE SYLVANIA 12AV7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP 1 VINTAGE SYLVANIA 12AV7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP

1 VINTAGE RAYTHEON 12AV7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP 1 VINTAGE RAYTHEON 12AV7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP

1 VINTAGE RCA 6S4A VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP 1 VINTAGE RCA 6S4A VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP

1 VINTAGE RAYTHEON 12AV7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP 1 VINTAGE RAYTHEON 12AV7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP

1 VINTAGE SYLVANIA 12AV7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP 1 VINTAGE SYLVANIA 12AV7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP

VINTAGE RCA 12AU7A NOS VACUUM TUBE TESTED AUDIO RADIO AMPLIFIER VINTAGE RCA 12AU7A NOS VACUUM TUBE TESTED AUDIO RADIO AMPLIFIER

1 VINTAGE TUNG SOL 6S4 VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMPLIFIER 1 VINTAGE TUNG SOL 6S4 VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMPLIFIER

1 VINTAGE SYLVANIA 6S4A NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMPLIFIER 1 VINTAGE SYLVANIA 6S4A NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMPLIFIER

1 VINTAGE RAYTHEON 12AV7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP 1 VINTAGE RAYTHEON 12AV7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP

VINTAGE SYLVANIA 6CG7 VACUUM TUBE TESTED STRONG AUDIO RADIO AMPLIFIER VINTAGE SYLVANIA 6CG7 VACUUM TUBE TESTED STRONG AUDIO RADIO AMPLIFIER

1 VINTAGE RCA 6X4 EZ90 NOS MIL SPEC VACUUM TUBE TESTED STRONG AUDIO RADIO AMP 1 VINTAGE RCA 6X4 EZ90 NOS MIL SPEC VACUUM TUBE TESTED STRONG AUDIO RADIO AMP

1 VINTAGE RCA 12AV7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP 1 VINTAGE RCA 12AV7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO AMP

1 Matched PAIR FULL MUSIC 300B/n Meshed Plate Audio Tubes Gold Pin Brass Base 1 Matched PAIR FULL MUSIC 300B/n Meshed Plate  Audio Tubes Gold Pin Brass Base

1 VINTAGE RCA 1G3GTA 1B3GT NOS VACUUM TUBES TESTED STRONG AUDIO RADIO AMPLIFIER 1 VINTAGE RCA 1G3GTA 1B3GT NOS VACUUM TUBES TESTED STRONG AUDIO RADIO AMPLIFIER

1 VINTAGE RCA 6AG7 NOS VACUUM TUBES TESTED STRONG AUDIO RADIO AMPLIFIER 1 VINTAGE RCA 6AG7 NOS VACUUM TUBES TESTED STRONG AUDIO RADIO AMPLIFIER

VINTAGE SRI 6AC7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO VINTAGE SRI 6AC7 NOS VACUUM TUBE TESTED STRONG AUDIO HAM RADIO

1 VINTAGE RCA 6AU4GTA VACUUM TUBES TESTED STRONG AUDIO RADIO AMPLIFIER 1 VINTAGE RCA 6AU4GTA VACUUM TUBES TESTED STRONG AUDIO RADIO AMPLIFIER

1 VINTAGE RCA 6SK7 NOS VACUUM TUBE TESTED STRONG AUDIO RADIO AMPLIFIER 1 VINTAGE RCA 6SK7 NOS VACUUM TUBE TESTED STRONG AUDIO RADIO AMPLIFIER

1 VINTAGE RCA 6AX4GT VACUUM TUBES TESTED STRONG AUDIO RADIO AMPLIFIER 1 VINTAGE RCA 6AX4GT VACUUM TUBES TESTED STRONG AUDIO RADIO AMPLIFIER

ECC82 12AU7 VALVO Inclined Getter Tube Audio AmplifiER Tests excellent ECC82 12AU7 VALVO Inclined Getter Tube Audio AmplifiER Tests excellent

Pre AMP Kit For DIY Tube 6N3 Buffer Audio Preamplifier–new Pre AMP Kit For DIY Tube 6N3 Buffer Audio Preamplifier--new

1 x Raytheon’1960 CK-5886 (DF703) subminiature audio/electrometer tube, NIB 1 x Raytheon’1960 CK-5886 (DF703) subminiature audio/electrometer tube, NIB

HIGH FIDELITY SYLVANIA JAN 6922 (6DJ8 ECC88) Vintage Microphone Amp Audio Tube HIGH FIDELITY SYLVANIA JAN 6922 (6DJ8 ECC88) Vintage Microphone Amp Audio Tube

VINTAGE SYLVANIA 6W4GT NOS VACUUM TUBE TESTED STRONG AUDIO RADIO AMPLIFIER VINTAGE SYLVANIA 6W4GT NOS VACUUM TUBE TESTED STRONG AUDIO RADIO AMPLIFIER

VINTAGE SYLVANIA 1G3GT 1B3GT NOS VACUUM TUBE TESTED STRONG AUDIO RADIO AMPLIFIER VINTAGE SYLVANIA 1G3GT 1B3GT NOS VACUUM TUBE TESTED STRONG AUDIO RADIO AMPLIFIER

2 pcs (One Pair) NOS NEOTRON 6J5G Audio Tubes ST Shape black Glass FRANCE 2 pcs (One Pair) NOS NEOTRON 6J5G Audio Tubes ST Shape black Glass FRANCE

8pc 9pin Bakelite vacuum tube socket valve base 12AX7 12AU7 ECC83 6N11 audio amp 8pc 9pin Bakelite vacuum tube socket valve base 12AX7 12AU7 ECC83 6N11 audio amp

NATIONAL ELECTRONIC TUBE NL-760P AUDIO TUBES,ONE PAIR-VINTAGE NATIONAL ELECTRONIC TUBE  NL-760P AUDIO TUBES,ONE PAIR-VINTAGE

4PCS VACCUM TUBE SOCKET SAVER SHIELD FOR SHUGUANG KT88 AUDIO tube amp DIY parts 4PCS VACCUM TUBE SOCKET SAVER SHIELD FOR SHUGUANG KT88 AUDIO tube amp DIY parts

Pair of Siemens E88CC audio double triode tube / NOS / NIB / FREE SHIPPING Pair of Siemens E88CC audio double triode tube / NOS / NIB / FREE SHIPPING

ECC40 TUNGSRAM Double Triode Audio TUBE / AA61 ECC40 TUNGSRAM Double Triode  Audio TUBE / AA61

Audio Research Classic Ad,SP-3 Preamp,Article,Tube,Nice Audio Research Classic Ad,SP-3 Preamp,Article,Tube,Nice

6i1P-k Special Audio Vibration Proof Soviet SRATOV TUBE ECH81 6AJ8 NOS 6I1P 6i1P-k Special Audio Vibration Proof Soviet SRATOV TUBE  ECH81 6AJ8  NOS 6I1P

2x AC2 PHILIPS Miniwatt audio tubes AC 2 – driver for AD1 2x AC2  PHILIPS Miniwatt  audio tubes  AC 2  -  driver for AD1

AC2 PHILIPS Miniwatt audio tube AC 2 – driver for AD1 AC2  PHILIPS Miniwatt  audio tube  AC 2  -  driver for AD1

AC2 PHILIPS Miniwatt audio tube AC 2 – driver for AD1 AC2  PHILIPS Miniwatt  audio tube  AC 2  -  driver for AD1

AC2 VALVO audio tube AC 2 – driver for AD1 AC2  VALVO  audio tube  AC 2  -  driver for AD1

6J5GT/G 6J5 KEN-RAD NIB WWII AUDIO TUBE 1945 6J5GT/G 6J5 KEN-RAD NIB WWII AUDIO TUBE 1945

Philips Holland ECC82 12AU7 audio tubes / amplifier valves NOS 6 pcs . Philips Holland ECC82 12AU7  audio tubes / amplifier valves NOS 6 pcs .

3LF4 VINTAGE CONSUMER ELECTRONICS NOS RADIO AUDIO TUBES Silver Plt. Foil Mica 3LF4 VINTAGE CONSUMER ELECTRONICS NOS RADIO AUDIO TUBES Silver Plt. Foil Mica

4 NOS RCA 6AN8A Radio Vacuum Tubes – 1970′s Vintage for Audio PreAmp 4 NOS RCA 6AN8A Radio Vacuum Tubes - 1970's Vintage for Audio PreAmp

4 X MATCHED 5963 12AU7 ECC82 RCA FOR HP AUDIO TUBES MADE IN USA WHITE PRINT 4 X MATCHED 5963 12AU7 ECC82  RCA FOR HP  AUDIO TUBES MADE IN USA WHITE PRINT

NEW FULLY SRPP TUBE PREAMPLIFIER Fully PCB ECC88 6922 6H30 AUDIO TUBE DIY C=1UF NEW FULLY SRPP TUBE PREAMPLIFIER Fully PCB ECC88 6922 6H30 AUDIO TUBE DIY C=1UF

5963 12AU7 ECC82 SYLVANIA LOW VOLTAGE AUDIO TUBE MADE IN USA GOLD PRINT 5963 12AU7 ECC82  SYLVANIA LOW VOLTAGE AUDIO TUBE MADE IN USA GOLD PRINT

HIGH FIDELITY RCA 6CG7 3 PLATE TESTASNEW MATCHED SET PAIR Vintage Amp Audio Tube HIGH FIDELITY RCA 6CG7 3 PLATE TESTASNEW MATCHED SET PAIR Vintage Amp Audio Tube

NOS GE / General Electric 6F8G Audio Tube NOS GE / General Electric 6F8G Audio Tube

12AU7 ECC82 MATCHED PAIR SYLVANIA AUDIO TUBES MADE IN USA NOS 12AU7 ECC82 MATCHED PAIR SYLVANIA AUDIO TUBES MADE IN USA NOS

12AV7 MATCHED PAIR SYLVANIA AUDIO TUBES MADE IN USA YELLOW PRINT 12AV7  MATCHED PAIR SYLVANIA AUDIO TUBES MADE IN USA YELLOW PRINT

3 X MATCHED 12AU7 ECC82 SYLVANIA BAD BOYS NOS AUDIO TUBES MADE IN USA YELLOW 3 X MATCHED 12AU7  ECC82  SYLVANIA BAD BOYS NOS AUDIO TUBES MADE IN USA YELLOW

RARE TESTSNEARNEW 1956 []SQR GTR RCA 5Y3GT 5Y3 BLACK PLATE Amp Audio Vacuum Tube RARE TESTSNEARNEW 1956 []SQR GTR RCA 5Y3GT 5Y3 BLACK PLATE Amp Audio Vacuum Tube

ECC82 12AU7 TELEFUNKEN MATCHED PAIR DIAMOND ON THE BOTTOM AUDIO TUBES GERMANY ECC82 12AU7 TELEFUNKEN  MATCHED PAIR  DIAMOND ON THE BOTTOM AUDIO TUBES GERMANY

6189 12AU7 USAF MATCHED PAIR GENERAL ELECTRIC AUDIO TUBES TRIPLE MICA 6189 12AU7  USAF  MATCHED PAIR GENERAL ELECTRIC  AUDIO TUBES TRIPLE MICA

5H 100mA Audio Power Choke for DIY Tube Amplifier 5H 100mA Audio Power Choke for DIY Tube Amplifier

1 x RCA JAN-5879 audio tube, 3-mica, silver plate, NIB, excellent condition 1963 1 x RCA JAN-5879 audio tube, 3-mica, silver plate, NIB, excellent condition 1963

5814A G. E CV4016 ECC82 12AU7 AUDIO TUBE NOS NIB US MADE TRIPLE MICA 5814A G. E CV4016 ECC82 12AU7  AUDIO TUBE NOS NIB US MADE TRIPLE MICA

3 X MATCHED 12AX7 ECC83 SYLVANIA AUDIO TUBES MADE IN USA 3 X MATCHED 12AX7  ECC83 SYLVANIA AUDIO TUBES MADE IN USA

5687WB MATCHED PAIR GENERAL ELECTRIC AUDIO TUBES MADE IN USA NOS 5687WB MATCHED PAIR GENERAL ELECTRIC  AUDIO TUBES MADE IN USA NOS

ECC85 RWN NEUHAUS RECORDING VERSION MATCHED PAIR YELLOW PRINT AUDIO TUBES ECC85  RWN NEUHAUS RECORDING VERSION MATCHED PAIR YELLOW PRINT  AUDIO TUBES

6DJ8 ECC88 6972 7308 MATCHED PAIR AMPEREX BY HP AUDIO TUBES MADE IN HOLLAND 6DJ8 ECC88 6972 7308 MATCHED PAIR AMPEREX BY HP  AUDIO TUBES MADE IN HOLLAND

5814A 12AU7 ECC82 MATCHED PAIR GENERAL ELECTRIC AUDIO TUBES MADE IN USA NOS 5814A 12AU7 ECC82 MATCHED PAIR GENERAL ELECTRIC  AUDIO TUBES MADE IN USA NOS

20pcs PHILIPS 344 HQ MKT 0.12UF 250V TUBE AMP CAPS FOR AUDIO!100nf 250v replace! 20pcs PHILIPS 344 HQ MKT 0.12UF 250V TUBE AMP CAPS FOR AUDIO!100nf 250v replace!

50pcs PHILIPS 344 HQ MKT 0.12UF 250V TUBE AMP CAPS FOR AUDIO!100nf 250v replace! 50pcs PHILIPS 344 HQ MKT 0.12UF 250V TUBE AMP CAPS FOR AUDIO!100nf 250v replace!

5879 PHILIPS ECG PREAMPLIFIER AUDIO TUBES NIB NOS 5879 PHILIPS ECG PREAMPLIFIER AUDIO TUBES NIB NOS

5814A ECC82 12AU7 ECC82 MATCHED PAIR SYLVANIA AUDIO TUBES TRIPLE MICA US MADE 5814A ECC82 12AU7 ECC82 MATCHED PAIR SYLVANIA  AUDIO TUBES TRIPLE MICA  US MADE

6189 12AU7 ECC82 MATCHED PAIR SYLVANIA AUDIO TUBES MADE IN USA NOS 6189 12AU7 ECC82 MATCHED PAIR SYLVANIA  AUDIO TUBES MADE IN USA NOS

2 RCA RADIOTRON UX 112A 12A GLOBE RADIO AUDIO HAM TUBES  2 RCA RADIOTRON UX 112A 12A GLOBE RADIO AUDIO HAM TUBES

12AT7 6201 GENERAL ELECTRIC AUDIO TUBE MADE IN USA 12AT7 6201 GENERAL ELECTRIC  AUDIO TUBE MADE IN USA

2 USED RCA RADIOTRON UX 171-A 71A GLOBE RADIO AUDIO HAM TUBES 2 USED RCA RADIOTRON UX 171-A 71A GLOBE RADIO AUDIO HAM TUBES

5814 12AU7 ECC82 MATCHED PAIR GENERAL ELECTRIC AUDIO TUBES MADE IN USA NOS 5814 12AU7 ECC82 MATCHED PAIR GENERAL ELECTRIC  AUDIO TUBES MADE IN USA NOS

2 CUNNINGHAM CX 380 80 280 GLOBE RADIO AUDIO TUBES 2 CUNNINGHAM CX 380 80 280 GLOBE RADIO AUDIO TUBES

Lots of 6pcs 12AT7WA ECC81 SYLVANIA AUDIO TUBES BLACK PLATES Lots of 6pcs 12AT7WA ECC81 SYLVANIA AUDIO TUBES BLACK PLATES

5814A 12AU7 ECC82 MATCHED PAIR RCA AUDIO TUBES MADE IN USA 5814A 12AU7 ECC82 MATCHED PAIR RCA AUDIO TUBES MADE IN USA

6189W 12AU7 ECC82 MATCHED PAIR SYLVANIA AUDIO TUBES MADE IN USA NOS 6189W 12AU7 ECC82 MATCHED PAIR SYLVANIA AUDIO TUBES MADE IN USA NOS

RCA CUNNINGHAM 71A RADIO AUDIO TUBES RCA CUNNINGHAM 71A RADIO AUDIO TUBES

33mm Tube Dampers Silicone O-Ring ft 6L6G 6L6GC 6CA7 6L6GCR tube Audio amps 20pc 33mm Tube Dampers Silicone O-Ring ft 6L6G 6L6GC 6CA7 6L6GCR tube Audio amps 20pc

CV4060 STC MATCHED PAIR AUDIO TUBES MADE IN ENGLAND NOS KT88 PIN COMPATIBLE CV4060 STC MATCHED PAIR AUDIO TUBES MADE IN ENGLAND NOS KT88 PIN COMPATIBLE

20pcs NOS ERO MKT1813 15nF 0.015UF 1000V 1kV CAPS HI-END TUBE AMP FOR AUDIO! 20pcs NOS ERO MKT1813 15nF 0.015UF 1000V 1kV CAPS HI-END TUBE AMP FOR AUDIO!

Audio Tube

How Small Can They Get? – A Look At Super-Miniature Audio Power Amplifiers

New generation super-miniature amplifiers are a result of the same miniaturization that has caused computers and cell phones to shrink. Products are shrinking at a rapid tempo. At the same time, vendors are packing in more and more features. The majority of audio amplifiers would be tube amps in the past. Even though a large number of fanatics still is fond of tube amplifiers, they have been replace by solid state amps for the most part.

Today’s amps combine traditional pre-amps and power amps and arrange everything neatly in a single box no larger than a VCR. New developments in audio technology in regard to power efficiency of have permitted the development of a new generation of super-miniature audio amplifiers, such as Amphony’s microFidelity Model 100. Even though these amps are as small as a deck of cards, they are capable to deliver up to 50 Watts power and easily drive a speaker to full volume.

“Class-A” and “Class-AB” amplifier topologies were the two primary amplifier architectures of previous audio amplifiers. These technologies have rather low power efficiency. Analog audio amplifiers will only convert between 20% to 30% of the consumed energy into audio while the remaining portion is radiated as heat. Analog amplifiers hence require substantial cooling which is done by heat sinks that are often bulky and prevent the amplifier from being made very small.

Digital “Class-D” amplifiers offer higher power efficiency than analog amplifiers – usually around 80% to 95% – and thus can be miniaturized. One major difficulty which has slowed the growth of “Class-D” amplifiers is audio distortion which is caused by nonlinearities of the switching output stage.

Some new amplifier technologies have emerged. Among those are “Class-T” and newer generation “Class-D” architectures. These types of new architectures, such as the technology used in Amphony’s Model 100 use a feedback mechanism. The output signal is fed back to the amplifier input. By using this feedback, the amplifier can compensate for nonlinearities of the output stage. This enables the distortion to be reduced to levels similar to analog audio amplifiers. At the same time the amplifier offers the high power efficiency of digital amplifiers.

These new generation miniature audio amplifiers open up applications where traditional amplifiers would fail, such as speaker installations where space is premium, including in-ceiling speakers and applications that connect speakers to a cable box or DVD/MP3 player.