FAQ: Frequently Asked Questions

SV-series (Power Amplifier & Integrated Amplifier)
Q1 Is it possible to connect a CD player directly with SV-amplifiers?
Q2 Is it necessary to adjust anything for SV-2A3 amplifier when I substitute 2A3 tubes?
Q3 Do the SV-2A3 and SV-300BE amplifiers have fixed bias level controls or do they need resetting manually?
Q4 The power output of SV-2A3 amplifier is only 3.5W per channel, can it drive a 88dB speaker?
Q5 Is it possible to use a different kind of output tube which does not appear in SV-amplifiers?
ex.) like using 45 tubes in "Single ended: SV-2A3, -VT25Limited, etc." or "Push-Pull ended: SV-2A3PE, -300BMKII, etc."
Q6 Which models of Tamura transformers are used in SV-amplifiers?
Q7 Do you have any upgrade transformer for SV-amplifiers?
Q8 Is it possible to purchase your special transformers and/or chassis which are used in SV-amplifiers separately?

SVC-series (Preamplifier & Line Control Amplifier)

Assembly series

Other question
Q1 Can you build a custom made amplifier?
ex.) like using 2A3 tube as the output and coupled with a Interstage transformer.

SV-series (Power Amplifier & Integrated Amplifier)
Q1 Is it possible to connect a CD player directly with SV-amplifiers?
A Yes, all of our SV-amplifiers can be used directly connecting with a CD player.
 
NOTE:  All of them have a volume control (knob) on the left of front panel which is available to adjust signal level from the input.
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Q2 Is it necessary to adjust anything for SV-2A3 amplifier when I substitute 2A3 tubes?
(NOTE:  this subject is regarding "adjustment for hum balancer".)
A It requires to minimize the hum noise with volume controls in the inside of the chassis for every substitution of 2A3 the Output tubes. (As for both 6SN7 the Driver tubes and 5U4G the Rectifier tube, there is no adjustment for every substitution.)
 
NOTE:  In case of the models which are used a Direct Heated Triode as the Output tube like SV-2A3PE, -300BMKII, -300BTE, -300BSM, -300BE and also -VT25Limited, it requires quite same adjustment as above for every substitution of the output tubes.
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Q3 Do the SV-2A3 and SV-300BE amplifiers have fixed bias level controls or do they need resetting manually?
(NOTE:  this subject is regarding "adjustment for bias".)
A A self(automatic) bias is used for all of our SV-amplifiers. So you don't have to adjust it at all when you operate the amplifier, even though you substitute the tubes.
 
NOTE:  There is no relations between the adjustments (Q2: "for hum balancer"  and  Q3: "for bias" ) because of referring to a different section in the circuit each other.
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Q4 The power output of SV-2A3 amplifier is only 3.5W per channel, can it drive a 88dB speaker?
A Normally, we recommend a speaker system which sensitivity is over 90dB/W/m at least with our SV-amplifiers. However, as your reference, we would like to inform you that we have ever used SV-2A3 mainly with B&W CDM1SE speaker which has 88dB/W/m in our shop, though we have the other speaker systems, too. (Reference: our listening point is about 2 meters away from the speakers) And it has no problem unless the volume is turned in order to get an extremely loud sound.
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Q5 Is it possible to use a different kind of output tube which does not appear in SV-amplifiers?
ex.) like using 45 tubes in "Single ended: SV-2A3, -VT25Limited, etc." or "Push-Pull ended: SV-2A3PE, -300BMKII, etc."
A It is necessary for us to design a new circuit with the amplifiers, even if it can be accepted with some modifications (which means a limited operation under the transformer's capacitance). In addition, it shall be considered as a kind of custom made. So we very much regret to say that it's impossible for us not only to show the details but also to build it as our products.
 
NOTE:  We cannot accept a custom made amplifier because of our circumstances.
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Q6 Which models of Tamura transformers are used in SV-amplifiers?
A All of the transformers (OPT, IT, Choke and Power) on our SV-amplifiers are specially manufactured by Tamura on our request. That is to say, they are not the standard models (ex. F-5002, F-7002, etc.) in Tamura's catalog. In addition, all of them (except for the power transformer of SV-300BSM) are made of silicon steel with "EI" type core. SV-300BSM's power transformer is made of silicon steel but with "C" type core.
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Q7 Do you have any upgrade transformer for SV-amplifiers?
A We very much regret to say that we don't have any optional transformers (this means a "Ready to Mount" type) now.
 
NOTE:  All of the transformers (OPT, Choke and Power) but except IT on our SV-amplifiers come with lead wires that specially manufactured by Tamura on our request. On the other hand, all of the standard models in Tamura's catalog come with taps only. (there is a big difference for the bottom appearance of the case.) That is to say, it's too hard to mount them on the chassis because there is a hitting part which should be cut off with it, though there are models (ex. F-5002, F-7002, etc.) having quite same size and measurement for fitting screw holes as already mounted ones on our SV-amplifiers.
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Q8 Is it possible to purchase your special transformers and/or chassis which are used in SV-amplifiers separately?
A We very much regret to say that they are not available separately because of our circumstances.
 
NOTE:  All of the transformers and chassis used in SV-amplifiers are available only with the kit and assembled unit as its complete product.
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Other question
Q1 Can you build a custom made amplifier?
ex.) like using 2A3 tube as the output and coupled with a Interstage transformer.
A We very much regret to say that we cannot accept a custom made amplifier because of our circumstances.
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