The A2500 is a tube type power amplifier kit that has been replaced with speaker terminals that are easy to use even for beginners. 6AQ8 for the first stage and 12AU7 for the phase reversal stage both use triodes. Since triodes are used across all stages, the sound is taut and bright, with excellent nude characteristics. The exterior has dullness over time, rust, and small scratches. Serial 560561 (Miura Kimiya)
Maintenance information: 2018.4.28 Maintained (printed circuit board resistor replaced. (Adjustment characteristics check OK) 2014.11.21 maintenance completed (input VR, vacuum tube socket, coupling capacitor, SP terminal, BIAS DC BAL, semi-VR, each deterioration exchange, adjustment, characteristic check OK)
Accessories: instruction manual
Main specifications: 6 RA8 push-pull 6 RA8 x 4/12 AU7 x 2/6AQ8 10W+10W W410 x H145 (with hood) x D190 mm 9.6 kg
Pair Tube Bi-triode Power Tube Made in USA JAN Measurement Value 60/60 (Rejection Value 40) With Original Box ※ The pair is judged based on GM value measured on the tv-7 test machine (Yosuke Kojima)
Accessories: original box
1 sold bi-triode power tube made in the USA JAN measurement value 58 (rejection value 40) with original box ※ Measured value is gm value measured by tv-7 tester (Yosuke Kojima)
Accessories: original box
Pair Tube Bi-triode Power Tube Made in USA JAN Measurement Value 60/60 (Rejection Value 40) With Original Box ※ The pair is judged based on GM value measured on the tv-7 test machine (Yosuke Kojima)
Accessories: original box
Pair Tube Bi-triode Power Tube Made in USA JAN Measurement Value 60/60 (Rejection Value 40) With Original Box ※ The pair is judged based on GM value measured on the tv-7 test machine (Yosuke Kojima)
Accessories: original box
Large triode sold per unit measured IP value: 50 mA (the best standard IP value for this amplifier is 50 mA) There is a getter burn with the original box ※ I checked the sound output and measured the plate current value with the test amplifier, and it was determined that the operation was good (Kojima Yosuke)
Accessories: original box
Pair tube 45Special compatible spherical triode fishing rod filament measurement value 94/86 (rejection value 55) *Pairs are judged based on GM values measured by test machine TV-7 (Kojima Yosuke)
Accessories: none
Pair tube 45Special compatible spherical triode fishing rod type filament measurement value 100/92 (rejection value 55) *Pairs are judged based on GM values measured by test machine TV-7 (Kojima Yosuke)
Accessories: none
Pair tube 45 Special/38142 compatible ball, direct heat triode, fishing rod type, filament measurement value 120/118 (rejection value 55) with original box ※ The pair was determined based on the GM value measured by the testing machine TV-7 (Kojima Yosuke)
Accessories: original box
Pair tube direct thermal triode made in England measured value 54/50 (rejection value 39) with replacement box The plate shape of the spring fixing part on the top of the head is slightly different on the left and right, and there is discoloration on the plate on one side ※ The pair was determined based on the GM value measured by the testing machine TV-7 (Kojima Yosuke)
Accessories: replacement box
Pair tube triode metal base, made in America, original with box ※ The pair was determined based on the EM value measured by the SENCORE TC-162 tester (Kojima Yosuke)
Accessories: original box
The large triode print sold in Japan has disappeared, but I think it was made by NEC from the structure. Measured IP value: 45 mA (the best standard IP value for this amplifier is 50 mA) with the original box ※ I checked the sound output with the test amplifier and measured the plate current value, and it has been determined that the operation is good (Kojima Yosuke)
Accessories: original box
Pair tube, PX4 equivalent tube, direct thermal triode, made in England, measured value 54/52 (rejection value 39) with white box (there is writing on the box) *The pair was judged based on the GM value measured by the testing machine TV-7 (Kojima Yosuke)
Accessories: white box
Sold 1 bottle, 300B equivalent tube, direct heat triode tube, English tea base, double ring getter, measured value 66 (rejected value 58) with original box ※The measured values indicate GM values measured with the testing machine TV-7 (Kojima Yosuke)
Accessories: original box
Pair tube, triode, metal base, made in America, with original box*Pairs are determined based on EM values measured by the SENCORE TC-162 testing machine (Kojima Yosuke)
Accessories: original box
※Operation not checked. This is a standalone remote control for the TRIODE TRV-A300XR. If you have been looking for it, please take this opportunity. There is an exterior, small wounds, and dullness (Kobayashi Hitoshi)
Maintenance information: operation unconfirmed
Accessories: none
Pair tube triode for Hi-Fi made in Japan*Pairs are determined based on EM values measured with the test machine EM-604 (Yosuke Kojima)
Accessories: none
Pair tube, triode, metal base, made in America, comes with a box, is inexpensive because there are fewer gutters and there are burns ※Pairs are determined based on EM values measured with the SENCORE TC-162 test machine (Kojima Yosuke)
Accessories: white box
Pair tube, triode, metal base, made in America, with original box, the size of the glass tube is different on the left and right, but the internal structure is the same ※The pair is determined based on EM values measured with the SENCORE TC-162 test machine (Kojima Yosuke)
Accessories: white box
The price has been drastically reduced. 2024/1/15 sales price 118,000 yen pair tube 45 special compatible ball straight heat triode fishing rod type filament made in America measurement value 90/86 (rejected value 55) with white box*Pairs are determined based on gM values measured by testing machine TV-7 (Kojima Yosuke)
Accessories: white box
Pair tube direct heat triode tube, white base, made in Russia, measured value 80/80 (rejected value 58) with original box ※ pair is determined based on gM values measured by testing machine TV-7 (Kojima Yosuke)
Accessories: original box
Pair tube large transmission tube direct heat triode tube made in China gold base gold foot measured IP value 47mA/47ma (the best standard IP value for this amplifier is 50mA) with original box (part of the box is damaged) *Sound is checked with a test amplifier, plate current values have been measured, and it has been determined that operation is good (Kojima Yosuke)
Accessories: original box
Single sale direct heat triode tube, made in Russia, white base, measured value 78 (rejected value 58) with original box ※The measured values indicate gM values measured with the test machine TV-7 (Kojima Yosuke)
Accessories: original box
Pair tube direct heat triode tube made in Russia measured value 72/70 (rejected value 38) with original box (inner cushioning material has deteriorated) *Pairs are determined based on gM values measured with the testing machine TV-7 (Kojima Yosuke)
Accessories: original box
Pair tube direct heat triode tube American-made smoke measurement value 72/70 (rejection value 38) with white box (lid claws are missing) *Pairs are determined based on gM values measured by the testing machine TV-7 (Kojima Yosuke)
Accessories: white box
Pair tube direct heat triode tube American-made smoke measurement value 68/68 (rejection value 38) with white box (lid claws are missing) *Pairs are determined based on gM values measured by the testing machine TV-7 (Kojima Yosuke)
Accessories: white box
Pair tube double triode tube, made in America, JAN measurement value 74/72 (rejected value 32) *Pairs are determined based on gM values measured with the test machine TV-7 (Kojima Yosuke)
Accessories: white box
Pair tube double triode tube, made in America, JAN measurement value 80/76 (rejected value 32) *Pairs are determined based on gM values measured with the test machine TV-7 (Kojima Yosuke)
Accessories: white box
※Only 1 bottle Sun Valley Sorting Ball Direct Heat Triode, Brown Base, Gold Foot, Made in China, Measured Value 66 (Rejected Value 58) with white box*Measured values are GM values measured with the TV-7 testing machine (Kojima Yosuke)
Accessories: white box
Pair tube direct heat triode tube, white base, made in Russia, measured value 84/76, rejected value 58) with replacement box ※Pairs are determined based on gM values measured by testing machine TV-7 (Kojima Yosuke)
Accessories: replacement box
The price has been reduced. 2024/6/2 sales price 59,800 yen Triode line vacuum tube premain developed with the novel concept of an amplifier for women. With its compact, exquisite size and high design, it can be used in a variety of situations. The exterior is good with only a small scratch and there is little feeling of use. (Kobayashi Hitoshi)
Maintenance information: 2024.6.1 operation confirmed
Accessories: power cable
Main specifications: output 3W+3W (8Ω) vacuum tubes 6BQ5 x 2, 12ax7 x 2, dimensions W190 x D180 x H135 mm weight 4.7 kg
※It is inexpensive because it leaves cracks in the VOL. A headphone amplifier that allows you to enjoy the sound of 2 systems: a vacuum tube and a transistor. It has a built-in USB DAC compatible with 24 bit 96 kHz, and it is a blissful item that allows you to immerse yourself in both digital and analog worlds to your heart's content. Scratches on the transformer area are slightly noticeable. Serial 12060066 (Fujisawa Yukishi)
Maintenance information: 2024.6.3 operation confirmed (sound output OK, gaps remain in VOL)
Accessories: instruction manual, power cord
Main specifications: Vacuum tube using a class single headphone amplifier 6BM8 x 2 vacuum tube output 20Ω to 600Ω (45mW to 135mW) transistor output 12Ω to 300Ω (40mW to 135mW) frequency characteristics 10Hz to 50,000 Hz SNR 89dB power consumption 30W size W190 x H150 x D250 mm mass 4.7 kg
Pair tube, large triode tube, made in America, measured Ip value: 71 mA/71 mA (the best standard IP value for this amplifier is 75 mA) with original box*Sound is checked and plate current values are measured with a test amplifier, and it has been determined that operation is good (Kojima Yosuke)
Accessories: original box
Pair tube large triode tube made in America Actual measured Ip value: 70mA/70mA (the best standard IP value for this amplifier is 75mA) The inside of the tube with the original box is slightly burnt, and there is dirt adhering to the outside of the tube*Sound is checked with a test amplifier, and the plate current value has been measured, and it has been determined that the operation is good (Kojima Yosuke)
Accessories: original box
Pair tube earthquake-resistant military standard product special tube getter large triode tube with white box, measured IP value: 47/47 mA (the best standard IP value for this amplifier is 50 mA) *Sound is checked with a test amplifier, plate current values have been measured, and it has been determined that operation is good (Kojima Yosuke)
Accessories: white box
Pair Tube 45Special Compatible Ball Direct Heat Triode Tube Fishing Rod Type Filament Engraved Made in America Measured Value 110/106 (Rejected Value 55) It seems to be an unused item due to the state of the tube with the original box! *Pairs are determined based on the gM value measured by the test machine TV-7 (Kojima Yosuke)
Accessories: original box
Pair Tube 45Special Compatible Ball Direct Heat Triode Tube Fishing Rod Type Filament Engraved Made in America Measured Value 110/110 (Rejected Value 55) It seems to be an unused item due to the state of the tube with the original box! *Pairs are determined based on the gM value measured by the test machine TV-7 (Kojima Yosuke)
Accessories: original box
Pair tube 45 Special compatible ball straight heat triode tube fishing rod type filament measurement value 84/84 (rejected value 55) with white box*Pairs are determined based on gM values measured with the test machine TV-7 (Kojima Yosuke)
Accessories: white box
Pair tube direct heat triode tube American double square getter measurement value 62/56 rejection value 38) It is inexpensive because there are few getters with white boxes ※Pairs are determined based on gM values measured with the test machine TV-7 (Kojima Yosuke)
Accessories: white box
Pair tube 45 Special compatible ball straight heat triode tube fishing rod type filament measurement value 86/84 (rejected value 55) with white box*Pairs are determined based on gM values measured with the test machine TV-7 (Kojima Yosuke)
Accessories: white box
Pair tube 45 Special compatible ball straight heat triode tube fishing rod type filament measurement value 90/90 (rejection value 55) with white box*Pairs are determined based on gM values measured with the test machine TV-7 (Kojima Yosuke)
Accessories: white box
Pair tube, 211 equivalent tube, large triode tube, made in America, actual measured IP value: 47/47 mA (the best standard IP value for this amplifier is 50 mA) with original box ※ sound is checked with a test amplifier, plate current values have been measured, and it has been determined that operation is good (Kojima Yosuke)
Accessories: original box