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Yahoo Bid Home Appliances, Audio & Video, Camera Audio Equipment Amplifiers General Other
300Bシングル自作ステレオメインアンプ トランスドライブ・SRPPドライブ選択可能 リード・ボンネット付きシャーシ 300B付属
        

  • Product Quantity
    : 1
  • Starting Bid
    :30,000円
  • Highest Bidder
    : gui******** / Rating:15191
  • Listing Date
    :May 14, 2026 18:07
  • Bidding closes on
    :May 22, 2026 03:07
  • Auction Number
    :q1229911379
  • Condition
    :State it in the description
  • Automatic Extension
    :Yes
  • Authentication
    :No
  • Early Closing
    :Yes
  • Can I return the product?
    :no
  • Description
  • Q&A ()
  • Cost Estimator
  • Problem Item Response Procedur
Notes
  1. Plug-in electrical appliances are only shipped by air (shipping by sea requires commodity inspection)
    If the seller's evaluation is less than 10, there is a high risk of fraud. If you need to bid, please confirm that it is a trustworthy seller and leave a message telling the product ID to join the bidding for you.
  2. Please note: Sellers with a rating lower than 50 or an overall rating lower than 98% cannot provide compensation for non-arrival of goods. Please choose a reputable seller.
300Bの良さを聴き比べるために、NFBをかけずに、トランスドライブと、SRPPドライブを切り替えられるように設計しました。出力トランスはTANGOのオリエントコアFW-20-7S、ドライブトランスは橋本電気(山水トランス製造元)のH-1848A(7k:28k-CT)、電源系のトランスも余裕を持たせ、5AR4で整流しています。初段は12AU7Aパラの抵抗負荷にドライブトランスを繋げ、12BH7AのSRPPドライブのいずれかを選択できます。切り替えは、センターオフの電源SWで行い、上方(PL赤)でトランスドライブ、下方(PL緑)でSRPPドライブになります。
付属の300Bは中国系のノーブランドでテスト用ですが、十分に使用できます。PSVANE等、他の300Bと差し替える場合は、画像6にあるRCAプラグで300Bのカソード電圧を点検できるようになっており、キャップを外して、テスターで60~70Vであることが確認できれば正常に動作しています。その右側のSWは、このカソードとB電源を、大型のフィルムコンデンサでオンオフするもので、音質改善に効果のある側で使用します。なお、300Bのヒーターは、小型のSW電源基盤2枚で直流点火しています。
本機のゲインは、8Ω端子で、SRPPドライブ時は20dB(約10倍)、トランスドライブ時は10dBほど低くなります。出力は4.5W程度ですが、通常の視聴環境では不足はありません。帯域は高域が」SRPPドライブ時で35kHz(-1dB)、トランスドライブ時で18kHz(-1dB)、低域はいずれも20Hzまで伸びています。残留ノイズは、SW電源による高周波がわずかに乗りますが、可聴域はハムなどは聞こえません。
5年ほど前に製作し、サイドアンプとして時々聴いてきましたが、これまでにトラブルはありません。本機のトランスドライブの音は、スピーカーによりますが、女性ジャズボーカルに向いています。コンボやビッグバンドの場合は、SRPPドライブの方が切れのよい音で鳴ります。
トランス類をはじめ、抵抗・コンデンサも、Dale やOrange Drop 等、相応のものを使用しています。これらのパーツを生かして、回路変更をする場合は、自己責任で行ってください。不明点はご質問ください。
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Product Price JPY
Japanese Consumption Tax(10%) JPY

A 10% consumption tax is applied to goods and services in Japan. The price may include the tax or it may be added separately. Please check the price details when ordering.

Note: This is a domestic sales tax applied within Japan.

Japan Local Shipping Fee JPY Japan Local Shipping Fee Reference
Product Weight KG The maximum weight limit is 30 kg
International Shipping Methods
Proxy bidding and purchasing services are becoming increasingly convenient. However, overseas shopping carries certain risks and issues. To reduce these risks and enhance shopping safety, please be sure to read the following information:

1. International Shipping

   Air Freight: If the item status is not confirmed within two days after the arrival notice, any customer complaints cannot be addressed with the seller.

2. After Receiving the Product

Please confirm and inspect the product as soon as possible to ensure that the product specifications, quantity, accessories, and description are correct

If, unfortunately, there are any issues, you can refer to the following examples on how to report related product problems:
1. Example of missing product information
2. Example of product not matching provided information
3. Example of damaged product information

Important Notes: 1. If the seller is unwilling to ship overseas or is unaware that the product will be shipped overseas, the international shipping cost for returns or exchanges will need to be borne by the member. You may refer to the EMS e-Express fee inquiry from the post office. If it involves alcoholic beverages or items that affect flight safety, the post office cannot be used for shipment, and only DHL can be used to ship back to Japan.
2. During the product complaint handling period, please retain the complete outer packaging of the product (including the shipping label information), and refrain from attempting any repairs or altering the original condition. Any modifications may result in the inability to process the case.

3. After Inspecting the Product

After receiving and inspecting the item, if you have any questions, it is recommended to contact Letao within 2 hours. Here are some reminders:

1. Please do not unpack, use or repair the received item yourself, and be sure to keep the original packaging to facilitate subsequent handling of related matters, so as to avoid changes to the item that may cause the seller to be unwilling to process.

2. You can call customer service, and the customer service will leave a message for you as below. Please provide the following information:
"Hello, we will first help you establish a complaint case for Product ID: _______ .But we need you to 2-3 clear photos of the product issue, including photos of the product problem, product packaging, shipping details slip, and outer box. Send them to service@letao.my and inform us of your desired resolution (failing to provide this may result in an inability to process subsequent matters). After sending the email, notify us in the customer service message. We will confirm with the seller as soon as possible. and if there are any related questions, we will contact you through the customer service message. Thank you for your cooperation."

Please provide:
1. "Product ID"
2. Photo of the "Delivery Note" (if any)
3. Photos of the outer box (including inner and outer packaging)
4. Photos of the product (Please include relevant descriptions to help us confirm with the seller)

Important Notes:
1. Do not include foreign text or other products in the background of the image.
2. Please keep the complete product packaging (including the shipping label information), and refrain from repairing or altering the original condition on your own, as any changes may result in the case being unable to be processed.
3. Please provide the relevant information within 48 hours to avoid missing the golden hour for reflection and causing situations that cannot be handled.
4. Due to 99% of Japanese sellers being unwilling or unaware of shipping goods overseas, if a seller is willing to handle the issue, the goods must be sent back to Japan, and the international shipping costs incurred must be borne by the member. Letao will use postal EMS international express to send the goods back to Japan.
5. As the goods are purchased from overseas, it may take approximately one to two weeks to complete the relevant processing procedures when issues arise with the goods. Please be reminded that you can inquire about the approximate cost through the EMS service at the post office.

4. FAQ

1. Issue of Authenticity: If antique or branded goods are found to be counterfeit upon receipt, clear photos showing the differences between the genuine product and the imitation must be provided as evidence. If unable to provide relevant proof, assistance can be sought to find a third-party reputable organization for a premium authentication service .
2. Leaking Iron Teapot: If an antique iron teapot is leaking, please take clear photos of the leaking area and provide them.
3. Transport Damage: If the goods are damaged during international shipping (to the pickup point), you need to provide photos of the outer packaging of the parcel and clear photos of the damaged goods' outer packaging.

※ Note: Photos provided to sellers should not contain any foreign-related information.
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    Product name: 300Bシングル自作ステレオメインアンプ トランスドライブ・SRPPドライブ選択可能 リード・ボンネット付きシャーシ 300B付属
    Notes:
    Customer service hours:
    • Monday to Friday 10:00-18:00
    Customer service hotline:
    Customer Service Email: service@letao.my