scares the heck out of me
every time I hear someone talk about not grounding a case. Particularly around tubes. I read somewhere about all the people who died because they tried to fix 'double insulated' radios at home by plugging in some kind of power cord while the device was open. the cord was called a widow maker
every time I hear someone talk about not grounding a case. Particularly around tubes. I read somewhere about all the people who died because they tried to fix 'double insulated' radios at home by plugging in some kind of power cord while the device was open. the cord was called a widow maker
Walter - what have I done ?
We've got some real heavyweights contributing to the Alpha thread that has shifted it's way to valves, earth arrangements and now insurance claims ( made by our wives just before our funerals )
Actually I need to respond to something AndrewT mentioned last week and this has reminded me to get on with it.
I need to plan and word my question very carefully however - Andrew... are you reading this ?
Bad news re the Bursons - thought they were drop in units and required just a small mod ? see atached pic
I'm fairly sure they are good for up to 250ma
I'll contact Lucas direct re buffer - his lampizator drawings and comment can be a bit short of fine detail ( well, for me anyway )
He'll not be too impressed I've stuck with 6N6P's either....
Friend of Peter Daniels ? - what a cool friend to have - any freebies ?
Good luck with the ' re work '
Andrew
We've got some real heavyweights contributing to the Alpha thread that has shifted it's way to valves, earth arrangements and now insurance claims ( made by our wives just before our funerals )
Actually I need to respond to something AndrewT mentioned last week and this has reminded me to get on with it.
I need to plan and word my question very carefully however - Andrew... are you reading this ?
Bad news re the Bursons - thought they were drop in units and required just a small mod ? see atached pic
I'm fairly sure they are good for up to 250ma
I'll contact Lucas direct re buffer - his lampizator drawings and comment can be a bit short of fine detail ( well, for me anyway )
He'll not be too impressed I've stuck with 6N6P's either....
Friend of Peter Daniels ? - what a cool friend to have - any freebies ?
Good luck with the ' re work '
Andrew
Attachments
I got the first generation Bursons on a clearance sale. They are only 80ma. could be it is just too much for the -15v one to drive its consumer and the other -5v reg and it's consumers. I am going to take my time and rewire without the cascade. Each reg will be fed off the 24v rail independently. I am also going to mount them right at the tda1541 consummer with point to point twisted pair back to the rail. They are a bit bulky for this application. They do add quite a lump to the Arcam.
We do have a some notworthy members helping us sort this all out.
I meant to ask you what cap values you are using on your buffer? Feel free to PM if preferred. I have worked my way through Lukas stuff and may be able to help figure it out.
We do have a some notworthy members helping us sort this all out.
I meant to ask you what cap values you are using on your buffer? Feel free to PM if preferred. I have worked my way through Lukas stuff and may be able to help figure it out.
In case it helps, here is a picture of the lampizator output stage on my backup machine. It is playing while the Arcam goes back to the drawing board. It is running 6np6 tubes right off the I output of ad1860N dac chips btw and it sounds quite sublime.
I build the tube stage across the back panel. RCA output right beside the tubes which are close as possible to dac. The mains comes in on the left side. B+ power is the first pair of caps on the left. after the bridge, 2x100u 250v with 1k resistor linking the positive. Filtered power goes across the back with red/black twisted pair feeding via another 1k resistor another 100u cap for each tube. (so separate power supply to each & double filtered as Lukas recommends. The ground is as follows. Larger white wires take ground from rca neg to negative side of the first filter caps. Then another heavy wire takes it right back to the earth lead on the mains socket. There is very close to the mains a wire to a bolt in the chassis to ground the box
. At each tube I use the neg RCA tab as my first star point for collecting ground. Pin 9, the dac neg lead, and the neg side of the last crc filter all go there and then from there back as described. So there are multiple star points but they all allow current to flow away from the signal source to the mains. Similarly with the filter supply, the power comes from the mains to that second CRC filter. Here it is 2x10k u 25v caps separated by a 1r 5w resistor. In fact to get enough current for the hungry 6n6p I even bypass the 1 ohm resistor so its actually just a bridge followed by 20ku caps. I take the filtered DC on twisted pair to pins 4,5 of each tube. The neg side of the filter is grounded back (nuther white 18gauge wire) to the earth ground at left.So it is not neat. I am using dirt cheap caps from a surplus store and penny resistors. It is dead silent and sounds quite good. The arcam has all cool caps and more of them, chokes, and Kiwame resistors and sounds quite nice. I add this as a concrete example. This one did sound bad at first and I swaped out a pair of suspect caps.
Hope this helps.
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Burson shunts in!
Whew! In a mad soldering marathon I rewired and have Burson regs on -15v and -5v. As I suspected, there just was not enough power capacity in the -15 reg to power the rest. As soon as I removed the -5v LM337, the voltage shot up to 14.85 on pin 15. I then went point to point picking power right off the rail. Turns out I have 26.5v on the rail which is a bit scary as the BGN caps are only 25V rated. Seems they have a little buffer. Wired the -5v reg close to pin 26.
Board now looking even more like a mad scientist creation.
Checked voltage output on the reg. It was -5.00 spot on. I proceeded to wire it to the Oscon at pin 26. Voltage saged a bit under load. One thing that is cool about the regs is they are adjustable. With a little jeweler's screw driver I adjusted the voltages to be exactly -15.00v and -5.00. Plugged it into the system and music happened.
It's late, my wife calling me to come to bed, so only a couple of samples. I must say it is worth the effort. Not as dramatic as the DEM but same league. First impressions confirm the Burson marketing pitch. Yet more realistic sound stage. More 3d and very relaxed. Seems like some more detail. Need to do some serious listening on the weekend.
Thanks Simon for encouraging this step.
Walter
Whew! In a mad soldering marathon I rewired and have Burson regs on -15v and -5v. As I suspected, there just was not enough power capacity in the -15 reg to power the rest. As soon as I removed the -5v LM337, the voltage shot up to 14.85 on pin 15. I then went point to point picking power right off the rail. Turns out I have 26.5v on the rail which is a bit scary as the BGN caps are only 25V rated. Seems they have a little buffer. Wired the -5v reg close to pin 26.
Board now looking even more like a mad scientist creation.
Checked voltage output on the reg. It was -5.00 spot on. I proceeded to wire it to the Oscon at pin 26. Voltage saged a bit under load. One thing that is cool about the regs is they are adjustable. With a little jeweler's screw driver I adjusted the voltages to be exactly -15.00v and -5.00. Plugged it into the system and music happened.
It's late, my wife calling me to come to bed, so only a couple of samples. I must say it is worth the effort. Not as dramatic as the DEM but same league. First impressions confirm the Burson marketing pitch. Yet more realistic sound stage. More 3d and very relaxed. Seems like some more detail. Need to do some serious listening on the weekend.
Thanks Simon for encouraging this step.
Walter
Worth it then - way to go ?
I don't doubt Simon for a moment but he did his s' regs early on in his development - he swapped them from another tweaked machine right at the start.
I may be in a position to buy come September but I'd like to think it's a real step in relation to the investment needed - it won't be cheap compared to some of the things we've done lately -
I took a feed off the i/v op amps straight to the buffer tonight using my spare alpha dac board - result !!
No odd sounds and even less hum ....
Don't care why - it's just sublime considering the original state of the dac board. ( well, apart from the dem mod I tried on it )
So tomorrow I'll be ' at it again ' and will mod the good dac board and do the changes more neatly - I can then hear the buffer properly in the main system - minus all the other unwanted dac board components.
Still considering dc regulated heater supplies before I bolt it down properly though - it may completely silence it ( the hum now becomes audible well outside sensible listening volume settings ) wow !!
Let us know what happens when you've had a good listen to the Bursons - very interested in your progress with this.
Oh, one more thing....we've got to do something with i2S to get the max benefit from DEM - looking into this now and will flag it all up as soon as I understand it.
erm...that'll be December then
Best Wishes
Andrew
I don't doubt Simon for a moment but he did his s' regs early on in his development - he swapped them from another tweaked machine right at the start.
I may be in a position to buy come September but I'd like to think it's a real step in relation to the investment needed - it won't be cheap compared to some of the things we've done lately -
I took a feed off the i/v op amps straight to the buffer tonight using my spare alpha dac board - result !!
No odd sounds and even less hum ....
Don't care why - it's just sublime considering the original state of the dac board. ( well, apart from the dem mod I tried on it )
So tomorrow I'll be ' at it again ' and will mod the good dac board and do the changes more neatly - I can then hear the buffer properly in the main system - minus all the other unwanted dac board components.
Still considering dc regulated heater supplies before I bolt it down properly though - it may completely silence it ( the hum now becomes audible well outside sensible listening volume settings ) wow !!
Let us know what happens when you've had a good listen to the Bursons - very interested in your progress with this.
Oh, one more thing....we've got to do something with i2S to get the max benefit from DEM - looking into this now and will flag it all up as soon as I understand it.
erm...that'll be December then
Best Wishes
Andrew
The work on this Sony looks very neat and tidy - lampization expert !!
Once I finish some stuff ( loads ) I'll do a proper lampz job and see what happens.
Staying focused on one task is the hard part.
My wife just did what yours did last night...wonder what she wants
No....it's not my birthday - I can assure you
Andrew
Once I finish some stuff ( loads ) I'll do a proper lampz job and see what happens.
Staying focused on one task is the hard part.
My wife just did what yours did last night...wonder what she wants
No....it's not my birthday - I can assure you
Andrew
Thanks Andrew. I will keep you posted on sreg impressions. I think they are at some point a must have, however I think they are very overpriced. In my relatively simple box I need 3 for the TDA1541a, one for the clock and minimum one for the pcm2706 chip. If I recall it has multiple power consumers, so the ultimate would be one per consumer. If these things are $50+ ea, then it would add up fast. I got lucky. A local parts supplier Parts ConneXion - The authority on hi-fi DIY parts and components
is having a summer sale. The old Bursons were on 50% and on that they had 20% off. So at $15 ea and only picking up 2 it was great value on the sound. No where near the pay back of your $1 DEM deal however.
My quest then will be to find ways to do DIY regs on the cheap. Peter D has come up with mods to his 1543 DAC that use shunt regs. He also points out that some series regs they played with were just about as good. They look like they are a pretty simple parts list. http://www.diyaudio.com/forums/audio-sector/187748-pushing-limits-tda1543-nos-dac.html He uses some exotic parts, but when there are only a few we might be able to build something very good on the cheap.
I also think that as we get into building regs, DEM attenuators and tube output stages that the quality of resistors will turn out to be equally important as caps, and could get as pricey. I am also interested in EcDesigns work on home built helical resistors. I can only imagine if we start listening to Mr Daniel's tastings next thing we'll be needing nude vishay's in our xmas stocking.
So as you branch out into optimizing the I2S, I will see if I can come up with a cost effective home brew sreg.
Glad to hear the tube buffer is coming to life. They are quite wonderful. I was thinking that the other thing that could mess you up would be the value or integrety of the R2 resistor from grid to ground. In your long list of projects, you will have to evolve to no Opp amp even if it means you move to the 6n2p. I think you need to pick up the parts for DC on the filament power.
Cheers
is having a summer sale. The old Bursons were on 50% and on that they had 20% off. So at $15 ea and only picking up 2 it was great value on the sound. No where near the pay back of your $1 DEM deal however.
My quest then will be to find ways to do DIY regs on the cheap. Peter D has come up with mods to his 1543 DAC that use shunt regs. He also points out that some series regs they played with were just about as good. They look like they are a pretty simple parts list. http://www.diyaudio.com/forums/audio-sector/187748-pushing-limits-tda1543-nos-dac.html He uses some exotic parts, but when there are only a few we might be able to build something very good on the cheap.
I also think that as we get into building regs, DEM attenuators and tube output stages that the quality of resistors will turn out to be equally important as caps, and could get as pricey. I am also interested in EcDesigns work on home built helical resistors. I can only imagine if we start listening to Mr Daniel's tastings next thing we'll be needing nude vishay's in our xmas stocking.
So as you branch out into optimizing the I2S, I will see if I can come up with a cost effective home brew sreg.
Glad to hear the tube buffer is coming to life. They are quite wonderful. I was thinking that the other thing that could mess you up would be the value or integrety of the R2 resistor from grid to ground. In your long list of projects, you will have to evolve to no Opp amp even if it means you move to the 6n2p. I think you need to pick up the parts for DC on the filament power.
Cheers
The plot thickens....did the ' i'v op amp out ' thing to my good dac and the odd sound mentioned above is right there again - gone is the hum but I have what I now would describe as digital hash with the cd player on but not playing - what on earth is this ?
Maybe I should apply some ferrite beads on my DEM bits around the dac.
Doesn't happen with the un - modded DAC board...damn
I have music though and it's excellent.
I'll let you know if I fix it......all this work and then I create some other bloody issue
This is where my ignorance ruins the hobby for me.
I'll find it...make no mistake
Andrew
One thing I've been reminded of recently is the resistors that are in-line from the data and clock signals feeding the DAC. Someone was talking about optimal resistors for such things so I wondered if there was scope for adjusting values (perhaps even using a scope lol) or at least upgrading to "low noise" types e.g. Holco H4. The latter option is cheap and easy. At the very least it'd look cool to have black resistors on that audio board!
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