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I know we want full-wave tube rectifier circuit instead of Hybrid or solid state rectifier circuit with FET.
After a week of negotiation with Mr Fujita, he finally agrees to have full wave rectifier circuit with two chokes for this 45 project.
There are a lot of compromise to make this 45 tube project, including the designer and the parts suppliers.
Hashimoto will not modify their design to fit our design.
As a result, we cannot use Hashimoto PT for 230V setting.
Thank you Mr. Per Lundahl. He will design the PT for this project (115/230V)
For the OPT, I will offer two versions so you can pick your output transfomer.
Lundahl : the combination of LL3720/1663 (5K/8OHM). The combination of LL3720/1663 has a very good frequency response.
(From Lundahl : we are using a new winding structure to minimize destructive capacitive coupling between primary and secondary windings.
This results in an improved high-frequency response.)
Hashimoto : H-20-7U
more to come.....
I know we want full-wave tube rectifier circuit instead of Hybrid or solid state rectifier circuit with FET.
After a week of negotiation with Mr Fujita, he finally agrees to have full wave rectifier circuit with two chokes for this 45 project.
There are a lot of compromise to make this 45 tube project, including the designer and the parts suppliers.
Hashimoto will not modify their design to fit our design.
As a result, we cannot use Hashimoto PT for 230V setting.
Thank you Mr. Per Lundahl. He will design the PT for this project (115/230V)
For the OPT, I will offer two versions so you can pick your output transfomer.
Lundahl : the combination of LL3720/1663 (5K/8OHM). The combination of LL3720/1663 has a very good frequency response.
(From Lundahl : we are using a new winding structure to minimize destructive capacitive coupling between primary and secondary windings.
This results in an improved high-frequency response.)
Hashimoto : H-20-7U
more to come.....
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Thank you so much Victor for all your work to make this happen!
I don’t want to add more to your plate, but any thoughts on having an amorphous option for the Lundahl OT? Maybe Amorphous is not necessary or possibly even would be too much with the new Lundahl winding structure??
vkung said:We received the sample HASHIMOTO trafos
We found that the creeping distance for 230V spec is not wide enough.
It has only 3-4mm. The standard requires 6mm
Therefore, this PT cannot be used in 220-240V environment.
To make it usable in 220-240V environment, the PT needs modification - HASHIMOTO needs to redesign the PT.
But they are not willing to make any change in their products.
In this case the 45 tube amp project will only offer 120V version..
If customers in 220-240V environment are willing to purchase, they must use step down transformer
This is the phototype to test all major components.. The production version is very attractive ...
Mr Fujita is working hard to design this 45 tube amp project
LL3720 is 6K
The low exchange rate allows us to use Hashimoto H20-7U
Victor, how did we go from H-20-7U to H-507S
sure but for those of us who plan to use the amp to drive a speaker top to bottom, would it not be better to have bandwidth headroom of the H-20-7U rated 25Hz - 70KHz +/- 2dB over the H-507S 45Hz - 90KHz +/- 3dB spec.?
If correct and H-507S were as much a price point decision as layout size is it unreasonable to suggest the chassis layout allow enough room to offer the option to use H-20-7U ?
