Ya I was just wanting to get up to speed. Usually post #1 would be the go to place to get an overview of the project. I saw people talking about hyno, hypno and mesmerize on the last couple of pages... just wondering what the differences between them were? I take it they will all be replaced with this hot-rodded hynotize version?
I didn't realize it needed a 50VA transformer. I am confused because I thought it could run without heatsinks. So is that true or is current/power draw really quite high?
Tea-Bag didn't point me to a thread but I guess you mean this one. It's 145 pages so... I guess I should start now
I didn't realize it needed a 50VA transformer. I am confused because I thought it could run without heatsinks. So is that true or is current/power draw really quite high?
Tea-Bag didn't point me to a thread but I guess you mean this one. It's 145 pages so... I guess I should start now
As much as I enjoy this forum I really freakin' wish you could modify posts and easily create stickies with all the pertinent information for a project in one place. Having to slog through *multiple* threads with >100 pages just to get up to speed on a project is a nightmare...
Ya I was just wanting to get up to speed. Usually post #1 would be the go to place to get an overview of the project. I saw people talking about hyno, hypno and mesmerize on the last couple of pages... just wondering what the differences between them were? I take it they will all be replaced with this hot-rodded hynotize version?
I didn't realize it needed a 50VA transformer. I am confused because I thought it could run without heatsinks. So is that true or is current/power draw really quite high?
Tea-Bag didn't point me to a thread but I guess you mean this one. It's 145 pages so... I guess I should start now
The difference between the two is the Mezmerize version has relays to select up to six different inputs. The Hypnotize has a single source input on the PCB. It's questionable that there will be anymore of the Mezmerize boards ordered. Not enough people asking for them with the group buy. But the schematic is in the thread if you want to build that option.
You do not have to use a 50VA transformer for this pre-amp. I think that the reason for it is more a question of over-building the power supply. But I could be mistaken. The Hypnotize that I have built runs quite cool at idle.
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mr.duck - that's basically it. Hypnotize was single input, Mesmerize was 6 input, relay switched, with space for a potentiometer. Now both replaced by this "hot rod" Hypnotize in the works. Original idea ran small CCS current, without need for 'sinks. Cool guys these days running heavy shunt current with a resistor change, appropriate heat sinks or bolted to floor. Must be the mother of all buffers, Nelson's original concept raised through the roof with killer supplies, and no caps in the path. Build it.
The hot-rodded hynotize version runs at over 200mA per leg, thus a "safe" Xfrmr is aprox. 50 VA.
I have the classical version of the DCB1 (not the hot-rodded). Having raised the CCS, so more current is being sucked from the main filter capacitors, would it be clever to add some more capacitor? Because of the more current constant consumption, maybe 2x4700uF is too low...
Regards,
Regi
Regards,
Regi
Hi,
try measuring the ripple at the smoothing capacitors.
Or calculate the theoretical ripple using Capacitance and Current.
try measuring the ripple at the smoothing capacitors.
Or calculate the theoretical ripple using Capacitance and Current.
Regi:
On the projected ''blue'' there are four positions for 10mm lead pitch snap-in caps plus 7.5mm option, and space around, so to fit favorite little monsters.
The 4700uF proved to still hold around 200mA but if you can fit any higher value 7.5mm lead pitch that the classic pcb supports, is rather welcome when hot rod.
On the projected ''blue'' there are four positions for 10mm lead pitch snap-in caps plus 7.5mm option, and space around, so to fit favorite little monsters.
The 4700uF proved to still hold around 200mA but if you can fit any higher value 7.5mm lead pitch that the classic pcb supports, is rather welcome when hot rod.
I have a 15v AC-AC adapter. It's rated for 500mA so that should be enough then? It's only 7.5VA though.
Using the 68//68R or 100R//100R//100R low consumption Rset, it will ask 60mA per rail, constant. I.e. 3.6VA from a 15-0-15VAC.
we have been here before, discussing VA requirement.
A 3.6VA 15-0-15Vac transformer has a maximum continuous AC current of 120mAac.
When fed into a capacitor input filter the maximum continuous DC current rating becomes 60mAdc after applying the voltage and de-rating factor.
Taking 60mAdc from the 3.6VA transformer will make it run as hot as taking 120mAac from it.
If the relay draws some extra current and the LED draws some extra current and the CCS control draws some extra current then the 60mAdc of the shunt regulator will overload a 3.6VA transformer.
Many builders suggest and I support that body of opinion that the transformer should be rated so that continuous DC load is ~50% of the maximum rated DC current.
This would require a 9VA 15-0-15 transformer for a 60mA CCS Shunt regulator.
This is quite different from most transformer duty.
In amplifiers and such equipment the transformer runs much of the time at <10% of it's rating and copes admirably with short term peak currents that are upto and even in excess of it's maximum rating. That does not apply with a CCS+Shunt regulator.
A 3.6VA 15-0-15Vac transformer has a maximum continuous AC current of 120mAac.
When fed into a capacitor input filter the maximum continuous DC current rating becomes 60mAdc after applying the voltage and de-rating factor.
Taking 60mAdc from the 3.6VA transformer will make it run as hot as taking 120mAac from it.
If the relay draws some extra current and the LED draws some extra current and the CCS control draws some extra current then the 60mAdc of the shunt regulator will overload a 3.6VA transformer.
Many builders suggest and I support that body of opinion that the transformer should be rated so that continuous DC load is ~50% of the maximum rated DC current.
This would require a 9VA 15-0-15 transformer for a 60mA CCS Shunt regulator.
This is quite different from most transformer duty.
In amplifiers and such equipment the transformer runs much of the time at <10% of it's rating and copes admirably with short term peak currents that are upto and even in excess of it's maximum rating. That does not apply with a CCS+Shunt regulator.
Andrew,
Basic question for you. Partially related.
If I am running only one tap on a transformer, and I want to run the full 50% load of the transformer, is this possible, or with one tap, are we reserved to 25% in class A?
Regards,
Basic question for you. Partially related.
If I am running only one tap on a transformer, and I want to run the full 50% load of the transformer, is this possible, or with one tap, are we reserved to 25% in class A?
Regards,
The taps in a transformer are current limited.
If you only use half the windings you can only draw half the maximum power.
If you only use half the windings you can only draw half the maximum power.
Something like in class A amplifiers? I mean in the sense that all the time there is almost the same constant consumption.
OK sounds good then. Just wondering Is there any particular reason 50VA was chosen for the transformer earlier?
The reason is we made it shooting for very good subjective quality. A 50VA isn't that expensive, its a typically much available rating and gave it space to play with higher CCS also. This is constant draw bias and cores sweat much easier. So we chose big. I would run it from 2 300VA R-Core even with 2A per side CCS, and nude Z foil signal path resistors if it was my fixation. Tight point to point air dielectric construction with solid silver hook up wire, monoblock 1.2 remote sensed regs, LSPD pot. But I am not that fixed.😀
lol that sounds wonderful 😀. I am still working through the other thread, Building a symmetrical psu B1 buffer, so I must be more annoying and ask, is there any subjective improvement in sound quality reported or any technical reason why using such over sized transformers would be beneficial? Also, does a high bias current have much affect on sound quality ?
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