I haven’t built any of the Elekit products for that reason. When the B+ is in the right range, a 80/ 280 is what I use in all of my builds. For that reason the 46 is an awesome amp powered by that rectifier. Here’s a SEP EL-84 I built powered by the amazing globe 280.
Thanks for being very thorough and doing a tube rectified project. I’ll bet its a great sounding amp!
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Here is the info for the 45 amplifer from Sunvalley - SV-S1645D - available in January 2024
The composition of the vacuum tubes:12AT7 x 1 or 12AX7 x 1
12AU7 X 2
45 X 2
274B/5U4G (tube rectifier only)
Output transformer Hashimoto H20-7U.
Choke and Power Transformer 115/230V custom made
Assembled by Sunvalley Japan with VCAP ODAM 0.1 X 2 + ODAM 0.22 X 2
Available in January 2024 - Only 25 units for the 1st productions
Pre-order price $2,475.00 (Between now - Nov 2023 )
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Thanks for all you do Victor. As with all your work, I’m sure this will be an outstanding and highly regarded amp. I love my 8600 with NFB and love my 8900 with or without the negative feedback—but I had my heart set on a zero negative feedback 45 amp for sometime. I have decided to follow my heart and build my own for the experience. That leaves one more available for a very lucky customer!
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NFB is a useful technology for improving the charactereistics of tube amps. It also has disadvantages.
Advantages:
Disadvantage
An increase in the amount of NFB not only makes the operation of the amp unstable, but can also degrade sound quality.
A litte bit of soya sauce will enhance the taste of food ... too much soya sauce will make the food too salty ...Enjoy..
Advantages:
- improvement of distortion factor
- improvement of frequecy characteristics
- improvement of damping factor
- reduction of residual noise
Disadvantage
- circuit complexity (phrase correction, compensationfor gain reduced by NFB)
- deteriotation of stability (oscillation risk)
- deteriotation of transient characteristics (decrease in clarity of sound)
An increase in the amount of NFB not only makes the operation of the amp unstable, but can also degrade sound quality.
A litte bit of soya sauce will enhance the taste of food ... too much soya sauce will make the food too salty ...Enjoy..
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I asked Decware about using NFB and here is the reply: Triodes do not require negative feedback because the tube has linear output. Pentodes and most solid state outputs are not linear in that the response is tipped up towards the highs. Negative feedback flattens the response and lowers the output impedance on those devices.
This is the reply from Mr Ohashi.. highly respected TUBE AMP designer in Japan
There have been opinions for a long time that NFB is not necessary for triode tubes. As he said, the fact that triodes have higher linearity than pentode is a relative point of view, and it does not mean that triodes are perfect.
To use a somewhat impolite analogy, suppose there was an opinion that a beautiful woman does not need makeup. Well, that may be true. There is no need to deny that they do not need anything because they are naturally beautiful. If she is a person who does not go out, there is no need to argue with her at all.
On the other hand, no one would deny that a beautiful woman dresses beautifully with the minimum of necessary and appropriate makeup. Of course, over-designed outfits are counterproductive, but as long as you are going out to meet someone, it is essential to have a minimum level of good manners in terms of appearance.
Therefore, there is absolutely nothing wrong with choosing no feedback in a homemade amplifier just for oneself. However, in the case of a general-purpose amp where you do not know how it will be used and by whom, it may be considered a form of good manners to use NFB to adjust the sound and characteristics before releasing it to the market.
Incidentally, the SV-S1645D has no problem in operation without feedback. However, there is a contradiction
Increase of residual noise
Narrowing of frequency response
Excessive gain
This may make it difficult to use the SV-S1645D with high-efficiency speakers or in combination with a preamplifier to set the proper volume.
There have been opinions for a long time that NFB is not necessary for triode tubes. As he said, the fact that triodes have higher linearity than pentode is a relative point of view, and it does not mean that triodes are perfect.
To use a somewhat impolite analogy, suppose there was an opinion that a beautiful woman does not need makeup. Well, that may be true. There is no need to deny that they do not need anything because they are naturally beautiful. If she is a person who does not go out, there is no need to argue with her at all.
On the other hand, no one would deny that a beautiful woman dresses beautifully with the minimum of necessary and appropriate makeup. Of course, over-designed outfits are counterproductive, but as long as you are going out to meet someone, it is essential to have a minimum level of good manners in terms of appearance.
Therefore, there is absolutely nothing wrong with choosing no feedback in a homemade amplifier just for oneself. However, in the case of a general-purpose amp where you do not know how it will be used and by whom, it may be considered a form of good manners to use NFB to adjust the sound and characteristics before releasing it to the market.
Incidentally, the SV-S1645D has no problem in operation without feedback. However, there is a contradiction
Increase of residual noise
Narrowing of frequency response
Excessive gain
This may make it difficult to use the SV-S1645D with high-efficiency speakers or in combination with a preamplifier to set the proper volume.
This will answer your concern about the misery of NFB
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