I wonder how many of us are using valve amps?
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Nice Dave! Who wouldn't?
These pair of 300845 sound fantastic!
These pair of 300845 sound fantastic!
An externally hosted image should be here but it was not working when we last tested it.
A bit off topic but what the hell 
All directly heated triode tubes.
EML AD1 two channel amp outputs (Sakuma style), WE VT-25 driver, EML 20A input tube, packed with interstages and chokes.
Nixi shows volume setting.
This is not the bottle neck in my audio system.................................
@ James,
While you are reworking the dac might I suggest to take off the plastic foil from the caps. This will improve dynamic and detail (the foil interacts with the AC current in the cap and this creates a memory effect that slows down charging and uncharging of the cap)
All directly heated triode tubes.
EML AD1 two channel amp outputs (Sakuma style), WE VT-25 driver, EML 20A input tube, packed with interstages and chokes.
Nixi shows volume setting.
This is not the bottle neck in my audio system.................................
@ James,
While you are reworking the dac might I suggest to take off the plastic foil from the caps. This will improve dynamic and detail (the foil interacts with the AC current in the cap and this creates a memory effect that slows down charging and uncharging of the cap)
Attachments
Yes indeed!
No technical specifics from me this evening, but I've re-worked a few things prior to fitting into my new cases this evening and from a couple of hours test listen to make sure these bits are working OK I'm in love with it all over again
An externally hosted image should be here but it was not working when we last tested it.An externally hosted image should be here but it was not working when we last tested it.An externally hosted image should be here but it was not working when we last tested it.
I'll do a proper explanation of a few bits very soon, but for now just wanted to say how thankful I am to experience such delights
James or anyone else in the know.
My chokes are in the post from Big Bear Audio. and I'm just about to order the caps from Hificollective.
Couple of questions What rating is the Bridge rectifier that I need.
The capacitors on your DAC and motherboard, what are they and what rating?
Thanks
James
A bit off topic but what the hell
All directly heated triode tubes.
EML AD1 two channel amp outputs (Sakuma style), WE VT-25 driver, EML 20A input tube, packed with interstages and chokes.
Nixi shows volume setting.
This is not the bottle neck in my audio system.................................
So back on topic should I be noticing any alias effects because the treble with the later board, CCS mod, decent caps and seaprate psus for digital and analogue sounds very pure to me-and to those who've compared it to top vinyl rigs??
I'm prepared to believe there may be some filtering effect through my intertsage or output txs-my amps are feedbackless with a response of 20-30k hz +- 3db
@juancho,
Just trust your ears, if it sounds good, it is good.
This dac beats any vinyl player!
Although I do not worship specifications, just compare the dac specs with that of a prime MC or MM element. Just look at the dynamic range and channel separation. Who are the vinyl guys kidding to think this would yield to higher resolution than the best digital rigs..........
And then the rumble of the platter drive, or the way the data is getting more compressed when raching the center of the record, or the dust in the grooves, or bad RIAA correction............. I can go on and on and on........
@sovereign1,
Caps rated 2200uf 25v for unregulated raw supply, on dac board use 100uf and 47uf 25 or 16v, all elna silmic. You can use oscon for digital if you like.
Go for shottkey diodes 60v or so, 2A or higher.
Regards,
Just trust your ears, if it sounds good, it is good.
This dac beats any vinyl player!
Although I do not worship specifications, just compare the dac specs with that of a prime MC or MM element. Just look at the dynamic range and channel separation. Who are the vinyl guys kidding to think this would yield to higher resolution than the best digital rigs..........
And then the rumble of the platter drive, or the way the data is getting more compressed when raching the center of the record, or the dust in the grooves, or bad RIAA correction............. I can go on and on and on........
@sovereign1,
Caps rated 2200uf 25v for unregulated raw supply, on dac board use 100uf and 47uf 25 or 16v, all elna silmic. You can use oscon for digital if you like.
Go for shottkey diodes 60v or so, 2A or higher.
Regards,
Sorry for being a bit dim. Its the rectifier http://www.o-digital.com/uploads/2179/2191-2/Bridge_Rectifier_KBPC2510_679.jpg
That I'm trying to source, I'm after the rating.Thanks !!!
Its the rating of the rectifier at the begining of this circuit that I'm after.
Thanks!
http://i58.tinypic.com/apjvw3.jpg
Thanks!
http://i58.tinypic.com/apjvw3.jpg
Its the rating of the rectifier at the begining of this circuit that I'm after.
Thanks!
http://i58.tinypic.com/apjvw3.jpg
Thanks!
http://i58.tinypic.com/apjvw3.jpg
raw psu high voltage
Hello everyone, hello great community. This is my first post here. I was following this forum for quite a long time, and seeing so many happy people with their constructions my native envy didn't let me wait too long :-D. And so, thanks to great advises of stijn001 and especially enormous help from Supersurfer I could make my decisions on how to proceed with my built. I thank you guys.
This is my first built ever. I’m not an electronic or whatsoever. Totally green in this matter. I learn as I proceed, and this forum is a great school lecture. Sometimes difficult to comprehend your technical language, but I’m working on it.
As I started to understand this electronic topic a bit I decided to join the forum. And I join with my first problem.
I have just put together row power supply with Lundahls, and I’m getting 17,5Vdc (no load) and 16,5Vdc (load) after the bridge and the same on the exit from the psu. Trafo gives me 12,5Vac. I attached some photos of the setup hopefully clear enough. All seems to be connected right way. Rectifier bridge is made from four Shottky diodes 15A 60V. I don’t really understand where problem could be. I can see that everyone is getting nice 12Vdc from their psus. Are the diodes connected wrong way?
Please help!
Voltage AC from trafo
Voltage behind the bridge with no load
Voltage on exit from psu, no load
Voltage on exit from psu, loaded
Bridge, bottom view
Bridge, top view
Setup, close up
Hello everyone, hello great community. This is my first post here. I was following this forum for quite a long time, and seeing so many happy people with their constructions my native envy didn't let me wait too long :-D. And so, thanks to great advises of stijn001 and especially enormous help from Supersurfer I could make my decisions on how to proceed with my built. I thank you guys.
This is my first built ever. I’m not an electronic or whatsoever. Totally green in this matter. I learn as I proceed, and this forum is a great school lecture. Sometimes difficult to comprehend your technical language, but I’m working on it
. As I started to understand this electronic topic a bit I decided to join the forum. And I join with my first problem.
I have just put together row power supply with Lundahls, and I’m getting 17,5Vdc (no load) and 16,5Vdc (load) after the bridge and the same on the exit from the psu. Trafo gives me 12,5Vac. I attached some photos of the setup hopefully clear enough. All seems to be connected right way. Rectifier bridge is made from four Shottky diodes 15A 60V. I don’t really understand where problem could be. I can see that everyone is getting nice 12Vdc from their psus. Are the diodes connected wrong way?
Please help!
Voltage AC from trafo
An externally hosted image should be here but it was not working when we last tested it.
Voltage behind the bridge with no load
An externally hosted image should be here but it was not working when we last tested it.
Voltage on exit from psu, no load
An externally hosted image should be here but it was not working when we last tested it.
Voltage on exit from psu, loaded
An externally hosted image should be here but it was not working when we last tested it.
Bridge, bottom view
An externally hosted image should be here but it was not working when we last tested it.
Bridge, top view
An externally hosted image should be here but it was not working when we last tested it.
Setup, close up
An externally hosted image should be here but it was not working when we last tested it.
Hi D3nsityD3nt I assume you do not have any voltage regulator in your PSU.
When you rectify AC voltages you need to multiply by 1.414 to get the DC voltage (approximately).
so your 12.5V AC X 1.414 = 17.65V which is pretty much what you are seeing so your PS is working as expected.
Note if you want a stable 12V you will need to implement a voltage regulator. 5V higher on the input is actually a good place to be to get a very stable 12V on the output. A regulator circuit based on the LM317 would do the trick, but as this is a DAC thread something a bit more rigourous than that may be required...
Tony.
When you rectify AC voltages you need to multiply by 1.414 to get the DC voltage (approximately).
so your 12.5V AC X 1.414 = 17.65V which is pretty much what you are seeing so your PS is working as expected.
Note if you want a stable 12V you will need to implement a voltage regulator. 5V higher on the input is actually a good place to be to get a very stable 12V on the output. A regulator circuit based on the LM317 would do the trick, but as this is a DAC thread something a bit more rigourous than that may be required...
Tony.
Like Supersurfer suggested, 2A or higher, the powersupply only draws +/- 1A at most (when using a 4 board DDDAC), which is roughly were you want the chokes to operate.
Impressive start, you've jumped straight into the deep end.
1Volt drop with load sound about right, I see you have a bleeder power resistor in the picture. Try and use a low value somewhere between 10R-30ROhm. If you put the first choke in "common" mode, you'll drop some more voltage too.
One trick I like a lot, is to unwind the secondary on your tranformer to the right voltage.
Sorry fellow DIYers I have to remind you that the shoot out is the way. DWJ is cetainly right and it is now long overdue. Doedde did this some time ago with great revelation.Weve seen some fantastic bits of kit posted too. Older unresolved issues sometimes get cleared up on the backwash from other, later issues, that get resolved in the seemingly random manner, but inevitably ultimately improving the SQ.
The supporting reproducing system is really an overriding factor. DHT or SS so different before you even start into the detail. Who would intentionally start a marathon with different starting times and places for the same race. But the best runner will stand out and surprise us
looking for opinions
Hello,
During my long stay in Asia i did visit this thread a few times. Sometimes very hard because a big boat did damage a big data cable in the see again in Vietnam. So speed was and still is? a big problem in Vietnam.
I remember reading that someone did build a dac with a single board and using bigger inductance chokes. Which is possible because of the lower current drawn by a single board.
Having some stock of chokes both high and low current i wonder which direction to take.
I think in the end i wanna end up with a device with an output transformer. Maybe even the one used by Doede himself.
Some transformers benefit or need multiple boards.
Multiple boards can only be used with the high current chokes.
It is safe to state that when using a single board you can use a 150ma 10/15 Henry choke usually found in tube amps and they will be better than the high current lundahls everryone is using here?
When using multiple boards you have no choiche other than to stick to the high current lundahls.
Using multiple boards will give more quality improvement than higher indictance power supply especially when using Doede's output transformer?
Greetings, Edward
Hello,
During my long stay in Asia i did visit this thread a few times. Sometimes very hard because a big boat did damage a big data cable in the see again in Vietnam. So speed was and still is? a big problem in Vietnam.
I remember reading that someone did build a dac with a single board and using bigger inductance chokes. Which is possible because of the lower current drawn by a single board.
Having some stock of chokes both high and low current i wonder which direction to take.
I think in the end i wanna end up with a device with an output transformer. Maybe even the one used by Doede himself.
Some transformers benefit or need multiple boards.
Multiple boards can only be used with the high current chokes.
It is safe to state that when using a single board you can use a 150ma 10/15 Henry choke usually found in tube amps and they will be better than the high current lundahls everryone is using here?
When using multiple boards you have no choiche other than to stick to the high current lundahls.
Using multiple boards will give more quality improvement than higher indictance power supply especially when using Doede's output transformer?
Greetings, Edward
Isn't the whole point NOT to use any kind of regulator when using chokes like Supersurfer and other have done ? A so called unregulated supply, or have i missed something ?
If you are getting around 16v out, and each of the Lundahls drop 2v, then you should get around 12v. A bleeder resistor will also help with around 1v drop.