Short info. Due to Brexit, the special DDDAC Sowter transformers were not available since December. I received a batch now, sold most of them from backlog but have two pair left now. Any one with interest, just email me or PM. When sold I will ordered a new batch to have some stock. As always, 30 days return right if you do not like them
Hello,
I will make it with some leftovers from my former employer. 300 grams each. Can interconnect them with the 2 mm aluminium panel so without power supply it will be below 5 kilograms.
Not sure how i will use them in the end . Probably for vibration killing properties i could give each rectangular it own " cap" with something attached so i can " fix it " on one spot in a sandfilled box. Between rectangular 2 cm of sand .
Can be done very easily.
The power supply will be heavy but i will have to consult Doede about that. I have been thinking about using a 61,7 F 18 V supercap from Eaton. Total current consumption will be between 250 and 300 mA and it needs to be on all the time. I am sure Doede will come up with a nice solution.
Greetings,Eduard
I will make it with some leftovers from my former employer. 300 grams each. Can interconnect them with the 2 mm aluminium panel so without power supply it will be below 5 kilograms.
Not sure how i will use them in the end . Probably for vibration killing properties i could give each rectangular it own " cap" with something attached so i can " fix it " on one spot in a sandfilled box. Between rectangular 2 cm of sand .
Can be done very easily.
The power supply will be heavy but i will have to consult Doede about that. I have been thinking about using a 61,7 F 18 V supercap from Eaton. Total current consumption will be between 250 and 300 mA and it needs to be on all the time. I am sure Doede will come up with a nice solution.
Greetings,Eduard
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Thanks for the congrats 
!
The 4 Boards are a minimum. with 8 boards the low frequency cutoff will actually shift one octave lower....
4 boards: -3dB point @ ~ 14 Hz
8 boards: -3dB point @ ~ 7 Hz
Just to mention, this would mean that with:
1 boards: -3dB point @ ~ 56 Hz (not practical of course)
2 boards: -3dB point @ ~ 28 Hz (weak bass performance in general)
3 boards: -3dB point @ ~ 19 Hz (might be ok, depending of rest of equipment)
as you see, 4 boards is an excellent choice and 8 boards tops that again. not only in low frequency cutoff, but also in sound quality: added space, micro details and overall increased "analog" experience
!The 4 Boards are a minimum. with 8 boards the low frequency cutoff will actually shift one octave lower....
4 boards: -3dB point @ ~ 14 Hz
8 boards: -3dB point @ ~ 7 Hz
Just to mention, this would mean that with:
1 boards: -3dB point @ ~ 56 Hz (not practical of course)
2 boards: -3dB point @ ~ 28 Hz (weak bass performance in general)
3 boards: -3dB point @ ~ 19 Hz (might be ok, depending of rest of equipment)
as you see, 4 boards is an excellent choice and 8 boards tops that again. not only in low frequency cutoff, but also in sound quality: added space, micro details and overall increased "analog" experience
Thank you so much, this mean there is a green light for 8 boards and Sowter TVC. Thanks a million for answering my call. I was going to build the Vacuum State RTP3D preamplifier but with the voltage out, there is no need for an active amplification stage - the less the better. A followup, your 1825e TVC compared to the 9335, what is the main difference - silver windings
?
no problems! The difference is not like silver windings or so.
The special DDDAC Sowter was designed by Brian Sowter specially with the DDDAC topology in mind. Being able to consume some DC offset at the input . This resulted in a very low number of windings and low Inductance. Meaning you need a very low output impedance (hence the 4 or more decks).
Now the side effect of these very low windings was that the transformer has a large bandwidth and less stray capacitance. May be simple said, less was better here sound wise
The special DDDAC Sowter was designed by Brian Sowter specially with the DDDAC topology in mind. Being able to consume some DC offset at the input . This resulted in a very low number of windings and low Inductance. Meaning you need a very low output impedance (hence the 4 or more decks).
Now the side effect of these very low windings was that the transformer has a large bandwidth and less stray capacitance. May be simple said, less was better here sound wise
I do agree on the last part, less capacitance is important. Same thing for FETs and Tubes, less gate to anode capacitance the more signal integrity (Miller capacitance). Hence why tubes and Lateral MOSFETs sound better.
Off-topic, Goldmund and Kinky Studio which is inspired by Goldmund is using Lateral MOSFETs for anyone who is curious.
Anyways, thanks for the info. I'll send you an email when I want to order a pair
Off-topic, Goldmund and Kinky Studio which is inspired by Goldmund is using Lateral MOSFETs for anyone who is curious.
Anyways, thanks for the info. I'll send you an email when I want to order a pair
Hello,
I am always using a choke input. Will even use one for DC input voltage to the lifepo4 from Canada.
FROM UpTone audio website
John Swenson on the benefits of a choke-filtered linear power supply:
The traditional cap only filter (transformer, diode bridge, big cap) produces raw DC with a sawtooth riding on top. That sawtooth produces lots of high frequency components that the regulator has to deal with. Traditional regulators do very well at low frequencies, but have lousy characteristics at high frequencies which means a fair amount of those high frequency components from the cap-only filter get through to the regulator. Fancy discrete regulators do well at blocking the high frequency components, but add cost and complexity to a PS. Our approach is to use a properly designed choke-based supply whose ripple is a perfect sine wave, no high frequency components, thus a traditional regulator works very well. The discrete regulator is not needed to deal with the high frequency components, since there aren't any.
All diode types except Schottkys emit a burst of ultrasonic noise as they turn off. This noise can go forward into the load circuit AND it can go back into the AC line, and it can also excite the transformer resonance. The "slow" diodes still have this ultrasonic noise. Schottkys are the only type which do not have this noise. Schottkys also usually have about half the voltage drop of other diode types and are usually faster. Which type to use depends a lot on what your supply looks like and what you are trying to optimize for.
With a traditional low voltage design with a large cap right after a bridge you get large current spikes, these produce a large amount of high frequency noise which needs to be filtered by what comes after the cap. In this type of circuit the slow diodes can help cut down on the extent of the high frequencies generated by the sharp high current pulse. BUT they still generate the ultrasonic noise.
This is another reason why we like to use the choke-based design. With the choke there is no steep high current pulse, so no disadvantage to Schottky diodes. You get the advantage of no ultrasonic noise, lower voltage drop (so lower power consumption in the diode) and no big massive current pulses.
Greetings, eduard
I am always using a choke input. Will even use one for DC input voltage to the lifepo4 from Canada.
FROM UpTone audio website
John Swenson on the benefits of a choke-filtered linear power supply:
The traditional cap only filter (transformer, diode bridge, big cap) produces raw DC with a sawtooth riding on top. That sawtooth produces lots of high frequency components that the regulator has to deal with. Traditional regulators do very well at low frequencies, but have lousy characteristics at high frequencies which means a fair amount of those high frequency components from the cap-only filter get through to the regulator. Fancy discrete regulators do well at blocking the high frequency components, but add cost and complexity to a PS. Our approach is to use a properly designed choke-based supply whose ripple is a perfect sine wave, no high frequency components, thus a traditional regulator works very well. The discrete regulator is not needed to deal with the high frequency components, since there aren't any.
All diode types except Schottkys emit a burst of ultrasonic noise as they turn off. This noise can go forward into the load circuit AND it can go back into the AC line, and it can also excite the transformer resonance. The "slow" diodes still have this ultrasonic noise. Schottkys are the only type which do not have this noise. Schottkys also usually have about half the voltage drop of other diode types and are usually faster. Which type to use depends a lot on what your supply looks like and what you are trying to optimize for.
With a traditional low voltage design with a large cap right after a bridge you get large current spikes, these produce a large amount of high frequency noise which needs to be filtered by what comes after the cap. In this type of circuit the slow diodes can help cut down on the extent of the high frequencies generated by the sharp high current pulse. BUT they still generate the ultrasonic noise.
This is another reason why we like to use the choke-based design. With the choke there is no steep high current pulse, so no disadvantage to Schottky diodes. You get the advantage of no ultrasonic noise, lower voltage drop (so lower power consumption in the diode) and no big massive current pulses.
Greetings, eduard
Ahh, thank you for answering this Eduard. This now make it rather obvious that, especially sensitive circuit (low voltage) need extra attention. I downloaded PSUD2 and gona model with the LL2771 choke for a CLC or CLCRC filter. So thank you for
proposing this earlier in the thread. I am also fairly confident that I will use the LT4320 active rectifier with Vishay Hexfred diode. Only heard good things about this one.
proposing this earlier in the thread. I am also fairly confident that I will use the LT4320 active rectifier with Vishay Hexfred diode. Only heard good things about this one.
Hello,
I have a few ll2771 to but you will to put the two " coils " in series to get a 2A choke.
The copy and paste i about a choke input and if you wanna do it right the best thing is to go for a choke input. Take care to use a bleeder resistor all the time.
I am using the SBYV28 or 27, the 3,5A ones and they work perfect.
Greetings,Eduard
I have a few ll2771 to but you will to put the two " coils " in series to get a 2A choke.
The copy and paste i about a choke input and if you wanna do it right the best thing is to go for a choke input. Take care to use a bleeder resistor all the time.
I am using the SBYV28 or 27, the 3,5A ones and they work perfect.
Greetings,Eduard
