Uploaded July 2025 | Updated September 2026, 2 weeks ago
We are going to try to fix the low voltage tube amplifier from Part 1 by swapping out the transistors, etc.
I bought this kit for projects (laser communicator, crystal radio, etc.)
Elec-Tube Amplifier Kit (For Crystal Radio, Etc.) Part 1/2 youtu.be/4Tbr-q-F8Dc
NOTES:
It came without a power supply (it requires an oddball 12 AC supply! NOT DC.) This added $8.50 to the $12.50 of the original kit.
No warranty guarantee.
No instructions, just a small slip of paper with Chinese writing INSIDE the kit (not noted in the online sales info):
“1. Electronic assembly kits (parts) are designed for teaching purposes and are only used for scientific research and experiments. Their technical indicators and parameters may not meet the standards of finished products. If you want to improve the performance indicators of the assembled product, the buyer can study and improve it on his own.”
“2. Some kits are equipped with faulty or poorly performing components. The purpose is to examine the assembler's ability to troubleshoot and improve performance. Troubleshooting and measuring and improving the performance indicators of accessories will help improve knowledge and skills.”
3. etc.
One tube came cloudy with bent pins.
When you search for replacement 6J1 tubes, you get LOTS of hits. Seems the 6J1 are notoriously are unreliable / low quality.
Lots of people suggest replacing the 6J1 (Chinese) with 6J1P (Russian) or 6AK5 (?) or GE 5654W (Not sure country of mfg or if it’s a drop in replacement)
Replacement tubes range from $8 (Chinese) to $50.
New tubes can double the cost. Worth checking the origin / type of tube supplied before buying.
Even at the low end I spent $29. That’s the price of finished 6J5 tube amp products, with nice cases, Bluetooth, etc.
Lots of reasons NOT to buy this kit: price, quality, looks, limited function (volume only), ….
We are going to try to fix the low voltage tube amplifier from Part 1 by swapping out the transistors, etc.
I bought this kit for projects (laser communicator, crystal radio, etc.)
Elec-Tube Amplifier Kit (For Crystal Radio, Etc.) Part 1/2 youtu.be/4Tbr-q-F8Dc
NOTES:
It came without a power supply (it requires an oddball 12 AC supply! NOT DC.) This added $8.50 to the $12.50 of the original kit.
No warranty guarantee.
No instructions, just a small slip of paper with Chinese writing INSIDE the kit (not noted in the online sales info):
“1. Electronic assembly kits (parts) are designed for teaching purposes and are only used for scientific research and experiments. Their technical indicators and parameters may not meet the standards of finished products. If you want to improve the performance indicators of the assembled product, the buyer can study and improve it on his own.”
“2. Some kits are equipped with faulty or poorly performing components. The purpose is to examine the assembler's ability to troubleshoot and improve performance. Troubleshooting and measuring and improving the performance indicators of accessories will help improve knowledge and skills.”
3. etc.
One tube came cloudy with bent pins.
When you search for replacement 6J1 tubes, you get LOTS of hits. Seems the 6J1 are notoriously are unreliable / low quality.
Lots of people suggest replacing the 6J1 (Chinese) with 6J1P (Russian) or 6AK5 (?) or GE 5654W (Not sure country of mfg or if it’s a drop in replacement)
Replacement tubes range from $8 (Chinese) to $50.
New tubes can double the cost. Worth checking the origin / type of tube supplied before buying.
Even at the low end I spent $29. That’s the price of finished 6J5 tube amp products, with nice cases, Bluetooth, etc.
Lots of reasons NOT to buy this kit: price, quality, looks, limited function (volume only), ….
