Product details
About shipping
1.Important: Import duties, taxes and other customs related charges all are not included into shipping cost . Buyers bear all responsibility for all extra charges incurred (if any).
2. We only ship to confirmed order addresses. Your order address MUST MATCH your Shipping address. We can ship to virtually any address in the world. Note that there are restrictions on some products, and some products cannot be shipped to international destinations.
3. When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.
4.Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound. The shipping rate can be showed at the Checkout page. There are two options for shippig as below.
A. Standard Shipping(≤2KG): The Post Registered Air Mail, USPS/ePacket, PostNL, Singapore Post, or DHL Global Mail
B. Express Shipping: EMS, DHL, UPS , or Fedex, Special Route.,etc. For faster shipping and smooth transaction, we will change the shipping company among them
C. Economy Shipping: China Air Post Mail / Parcel, Hongkong Air Post Mail / Parcel, or shipment by sea etc
RETURNS POLICY
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days). If you need to return an item, simply login to your account, view the order using the 'Complete Orders' link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
SELLER GUARANTEES
1. One year Manufacturer`s limited Warranty for defective items (excluding items damaged and/or misused after receipt). Accessories come with a 3-month warranty.
2. Defective items MUST BE reported and returned within the warranty period (with the original packaging, if possible). You must tell us what the defect is and give us your order number. WE DO NOT REPAIR OR REPLACE ITEMS WITH AN EXPIRED WARRANTY. You agree to all of the above-listed policies upon ordering on our store.
SHIPPING RATE
How to check the latest shipping cost, please follow steps below.
1. Click the ADD TO CART button;
2. Click the GO TO CART button;
3. Input your Country, State or Province, Postal/Zip Code;
4. Finally, click the CALCULATE SHIPPING
Standard Shipping(≤2KG) ---Through Post Registered Air Mail, ePacket or DHL Global Mail,.etc.
| Weight(KG) | Shipping Code | Shipping Cost(USD) |
| 0.1~0.2 |
Standard Shipping The Post 0.2
|
3 |
| 0.21~0.3 |
Standard Shipping The Post 0.3
|
4 |
| 0.31~0.4 | Standard Shipping The Post 0.4 | 5 |
| 0.41~0.5 | Standard Shipping The Post 0.5 | 7 |
| 0.51~0.6 | Standard Shipping The Post 0.6 | 8 |
| 0.61~0.7 | Standard Shipping The Post 0.7 | 11 |
| 0.71~0.8 | Standard Shipping The Post 0.8 | 13 |
| 0.81~0.9 | Standard Shipping The Post 0.9 | 15 |
| 0.91~1.0 | Standard Shipping The Post 1.0 | 17 |
| 1.01~1.0 | Standard Shipping The Post 1.1 | 19 |
| 1.11~1.2 | Standard Shipping The Post 1.2 | 20 |
| 1.21~1.3 | Standard Shipping The Post 1.3 | 21 |
| 1.31~1.4 | Standard Shipping The Post 1.4 | 22 |
| 1.41~1.5 | Standard Shipping The Post 1.5 | 23 |
| 1.51~1.6 | Standard Shipping The Post 1.6 | 24 |
| 1.61~1.7 | Standard Shipping The Post 1.7 | 25 |
| 1.71~1.8 | Standard Shipping The Post 1.8 | 26 |
| 1.81~1.9 | Standard Shipping The Post 1.9 | 27 |
| 1.91~2.0 | Standard Shipping The Post 0.8 | 28 |
Express Shipping ---Through Special Routes, EMS, DHL, UPS ,Fedex, or TNT. For faster shipping and smooth transaction, we will change the shipping company among them
| Weight(KG) | Shipping Code | Shipping Cost(USD) |
| 0~0.5 |
Express Shipping L0.5
|
17 |
| 0.51~1 |
Express Shipping L1.0
|
20 |
| 1.01~1.5 | Express Shipping L1.5 | 25 |
| 1.51~2 | Express Shipping L2.0 | 30 |
| 2.01~2.5 | Express Shipping L2.5 | 35 |
| 2.51~3 | Express Shipping L3.0 | 38 |
| 3.01~3.5 | Express Shipping L3.5 | 40 |
| 3.51~4 | Express Shipping L4.0 | 42 |
| 4.01~4.5 | ExpressShipping L4.5 | 44 |
| 4.51~5 | Express Shipping L5.0 | 47 |
| 5.01~5.5 | Express Shipping L5.5 | 59 |
| 5.51~6 | Express Shipping L6.0 | 62 |
| 6.01~6.5 | Express Shipping L6.5 | 65 |
| 6.51~7 | Express Shipping L7.0 | 68 |
| 7.01~7.5 | Express Shipping L7.5 | 71 |
| 7.51~8 | Express Shipping L8.0 | 74 |
| 8.01~8.5 | Express Shipping L8.5 | 77 |
| 8.51~9 | Express Shipping L9.0 | 80 |
| 9.01~9.5 | Express Shipping L9.5 | 82 |
| 9.51~10 | Express Shipping L10.0 | 86 |
| 10.01~10.5 | Express Shipping L10.5 | 103 |
| 10.51~11 | Express Shipping L11.0 | 107 |
| 11.01~11.5 | Express Shipping L11.5 | 110 |
| 11.51~12 | Express Shipping L12.0 | 114 |
| 12.01~12.5 | Express Shipping L12.5 | 118 |
| 12.51~13 | Express Shipping L13.0 | 122 |
| 13.01~13.5 | Express Shipping L13.5 | 126 |
| 13.51~14 | Express Shipping L14.0 | 130 |
| 14.01~14.5 | Express Shipping L14.5 | 134 |
| 14.51~15 | Express Shipping L15.0 | 137 |
| 15.01~15.5 | Express Shipping L15.5 | 140 |
| 15.51~16 | Express Shipping L16.0 | 143 |
| 16.01~16.5 | Express Shipping L16.5 | 146 |
| 16.51~17 | Express Shipping L17.0 | 149 |
| 17.01~17.50 | Express Shipping L17.5 | 152 |
| 17.51~18 | Express Shipping L18.0 | 155 |
| 18.01~18.50 | Express Shipping L18.5 | 158 |
| 18.51~19 | Express Shipping L19.0 | 161 |
| 19.01~19.5 | Express Shipping L19.5 | 164 |
| 19.51~20 | Express Shipping L20.0 | 167 |
| 20.01~20.5 | Express Shipping L20.5 | 170 |
| 20.51~21 | Express Shipping L21.0 | 173 |
| 21.01~21.5 | Express Shipping L21.5 | 176 |
| 21.51~22 | Express Shipping L22.0 | 179 |
| 22.01~22.5 | Express Shipping L22.5 | 182 |
| 22.51~23 | Express Shipping L23.0 | 185 |
| 23.01~23.5 | Express Shipping L23.5 | 189 |
| 23.51~24 | Express Shipping L24.0 | 192 |
| 24.01~24.50 | Express Shipping L24.5 | 195 |
| 24.51~25 | Express Shipping L25.0 | 198 |
Note:
1.This table of shipping rate will be added to the checkout. The shipping rate can be showed at the Checkout page. And, the table is for reference only. Final shipping rate is subject to actual checkout.
2.The shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.
3.If you have any questions about the shipping rate, pleas don't be hesitate to contact us through the ways as below.
Email: sales@iwistao.com
IWISTAO 50W 1 Piece Push-Pull Tube Amplifier Output Transformer Z11 EI Core 5.5KΩ / 6KΩ for 2A3 300B KT88 KT66 EL34 6L6
Model No: WHFTR-PPOPT5K50W
The IWISTAO 50W Push-Pull Output Transformer is designed for high-quality DIY vacuum tube power amplifiers using popular output tubes such as 2A3, 300B, KT88, KT66, EL34, 6CA7, 6L6, and 5881.
Built around a large 96 × 50 mm laminated EI core using Japanese Z11 0.35 mm silicon steel, the transformer is engineered for excellent low-frequency power handling, wide bandwidth, low insertion loss, and stable push-pull operation.

With a rated continuous output of 50W at 30Hz, it is particularly suitable for serious Hi-Fi tube amplifier projects where output transformer bandwidth and core capacity are critical to overall sound quality.
Four Options
|
Option |
Primary Impedance |
Insulation Material |
Frequency Response |
|
50-A Standard |
5.5KΩ |
Japanese Miki Insulation Paper |
3Hz–75kHz (-3dB) |
|
50-A DuPont |
5.5KΩ |
USA DuPont Insulation Paper |
3Hz–75kHz (-3dB) |
|
50-B Standard |
6KΩ |
Japanese Miki Insulation Paper |
3Hz–62kHz (-3dB) |
|
50-B DuPont |
6KΩ |
USA DuPont Insulation Paper |
3Hz–62kHz (-3dB) |
The 50-A version uses a 5.5KΩ primary, while the 50-B version uses a 6KΩ primary, allowing the transformer to accommodate different tube types, operating points, and push-pull amplifier designs.
The DuPont versions use upgraded USA DuPont insulation paper in place of the standard Japanese Miki insulation paper.
Key Features
- 50W continuous output power at 30Hz
- Designed for push-pull vacuum tube amplifiers
- Suitable for 2A3, 300B, KT88, KT66, EL34, 6CA7, 6L6, 5881, and similar tubes
- Primary impedance options: 5.5KΩ or 6KΩ
- Secondary output: 0–4Ω–8Ω
- Japanese Z11 0.35mm silicon steel EI laminations
- Large 96 × 50mm stacked core
- Imported British oxygen-free copper winding wire
- Japanese Miki insulation paper as standard (Optional upgraded USA DuPont insulation paper)
- Wide-bandwidth design
- Vertical mounting with side covers
- Approx. 3kg per piece
Specifications
1. Rated Output Power: 50W continuous at 30Hz
2. Primary Impedance: 50-A: 5.5KΩ or 50-B: 6KΩ
3. Secondary Impedance: 0–4Ω–8Ω
(Other impedance configurations may be available upon request).
4. Core Material: Japanese Z11 silicon steel, 0.35mm laminations
5. Core Size: 96 × 50mm EI laminated stack
6. Winding Wire: Imported British oxygen-free copper
7. Standard Insulation: Japanese Miki insulation paper
Optional Insulation: USA DuPont insulation paper
8. Frequency Response – 50-A:3Hz–75kHz, -3dB
Frequency Response – 50-B: 3Hz–62kHz, -3dB
(Frequency response measured with a 300B tube in-circuit, referenced to 0dB at 1kHz into an 8Ω load).
9. Mounting Style: Vertical mounting with side covers
10. Weight: Approx. 3kg / piece
11. Sizes:



Applications
This transformer is suitable for custom and DIY push-pull tube power amplifiers, including designs based on 300B, 2A3, KT88, KT66, EL34, 6CA7, 6L6, and 5881 output tubes.
The combination of a large Z11 EI core, oxygen-free copper windings, high primary-current capability, and wide frequency response makes it particularly suitable for Hi-Fi amplifier projects requiring strong low-frequency performance, good transient response, and extended high-frequency bandwidth.
Package / Ordering Note
The displayed price is for ONE output transformer.
For a stereo amplifier, please order 2 pieces.
An optional black resin-potted square cover is also available at additional cost.