Thought I'd do another report. So I had sibilance... I tidied up my input and output wiring a lot and changed the 220K for 540K to better match the ebay stepped 50k pot thats in there right now (lightspeed to come shortly).
Doing those things got rid of at least 80% of the sibilance
. So the other thing I've done since is swap out the 220R in the B1 part for some CMF55 dale 221R I had to had. Well, that has further reduced the sibilance. Now its just noticeable on a very few tracks, to the point where I can't really say if its just ermmm, explicit treble or a touch of sibilance. My test track for sibilance, the one I use all the time, is the speakers corner reissue of Ella and Louis, "April in Paris". Both voices have some sibilance (its on the CD too, not just vinyl) but I have used it so much that I can guage pretty accurately (I think!) whats too much or not. So right now, the DCB1 is pretty OK on this test.
Also good on massed violins (Buddy Holly, true love ways) and female vocals (Anna Netrebko, souvenirs CD).
Now, as I said earlier, I think my system is very sensitive to sibilance - those fostex drivers are pretty ruthless in showing up any harshness, and need top quality stuff to sound really good I think. Probably, 99.9% of people would never hear what I'm rattling on about. Unless you have a system that leans towards harshness, you won;t ever encounter any of this. None of the beta builders, nor anyone who has completed a DCB1 has reported this either.
The last few things to go have a look at is the AC input - mine is a bit low (using 12v secondaries) but I have a 15V Tx on its way (in Koln right now) which should remedy that. Also, I'm curious about increasing the current through the shunt by using 10R instead of 68R//68R. Seems to me, the more heat a thing gives off, the better it sounds!The other thing is that I may just keep an eye out for some nicer resistors for the B1 part. If I do an order soon for partsconnexion or similar I will include some in the order.
Someone asked me how did it compare to the regular B1. All I can say is that this DCB1, with basic parts/ebay stepped pot now sounds better than the regular B1 with tread power supply and extra RC filtering and lightspeed (with its own separate supply). Getting rid of the big 10uF cap and improving the PS obviously makes a big difference.
So as I have more things to report, I'll update here. I hope I haven't bored you, and have tried to explain what I'm hearing as accurately and truthfully as I can. Its one of the things that really helps when you're trying to decide what to build.
For completeness the gear I'm using:
Teres 340 clone, but with Teres bearing & platter, and battery PS & motor
Pass pearl preamp with lundhal step ups
shigaclone with buffalo DAC (counterpoint boards for output)
Squeezebox duet with Peter Daniels premium NOS DAC
DCB1 (and comparing this to regular B1 and Aikido pre)
Pass F5 (dual mono, Peter Daniels boards, all protection uninstalled)
Sachiko horns with FE206 drivers
Fran
Doing those things got rid of at least 80% of the sibilance
. So the other thing I've done since is swap out the 220R in the B1 part for some CMF55 dale 221R I had to had. Well, that has further reduced the sibilance. Now its just noticeable on a very few tracks, to the point where I can't really say if its just ermmm, explicit treble or a touch of sibilance. My test track for sibilance, the one I use all the time, is the speakers corner reissue of Ella and Louis, "April in Paris". Both voices have some sibilance (its on the CD too, not just vinyl) but I have used it so much that I can guage pretty accurately (I think!) whats too much or not. So right now, the DCB1 is pretty OK on this test. Also good on massed violins (Buddy Holly, true love ways) and female vocals (Anna Netrebko, souvenirs CD).Now, as I said earlier, I think my system is very sensitive to sibilance - those fostex drivers are pretty ruthless in showing up any harshness, and need top quality stuff to sound really good I think. Probably, 99.9% of people would never hear what I'm rattling on about. Unless you have a system that leans towards harshness, you won;t ever encounter any of this. None of the beta builders, nor anyone who has completed a DCB1 has reported this either.
The last few things to go have a look at is the AC input - mine is a bit low (using 12v secondaries) but I have a 15V Tx on its way (in Koln right now) which should remedy that. Also, I'm curious about increasing the current through the shunt by using 10R instead of 68R//68R. Seems to me, the more heat a thing gives off, the better it sounds!
The other thing is that I may just keep an eye out for some nicer resistors for the B1 part. If I do an order soon for partsconnexion or similar I will include some in the order.Someone asked me how did it compare to the regular B1. All I can say is that this DCB1, with basic parts/ebay stepped pot now sounds better than the regular B1 with tread power supply and extra RC filtering and lightspeed (with its own separate supply). Getting rid of the big 10uF cap and improving the PS obviously makes a big difference.
So as I have more things to report, I'll update here. I hope I haven't bored you, and have tried to explain what I'm hearing as accurately and truthfully as I can. Its one of the things that really helps when you're trying to decide what to build.
For completeness the gear I'm using:
Teres 340 clone, but with Teres bearing & platter, and battery PS & motor
Pass pearl preamp with lundhal step ups
shigaclone with buffalo DAC (counterpoint boards for output)
Squeezebox duet with Peter Daniels premium NOS DAC
DCB1 (and comparing this to regular B1 and Aikido pre)
Pass F5 (dual mono, Peter Daniels boards, all protection uninstalled
)Sachiko horns with FE206 drivers
Fran
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Cool progress. Just substitute one input cable with some non thick, plain quality shielded coax and make a comparison between that and the open cabling you use for checking out the HF transients specifically. See if there is more potential in that approach. Maybe it will not be best overall, but can there be some noise picked up by cabling to be shielded off, that roughens it a bit? Maybe you leave that for last after you got LSPD and final trafo, if there is some coolness in HF still.
Banned
Joined 2002
Thanks for the link Malka07,
Shunt Pot Volume Control - World-Designs-Forum
Very good read, i run a passive pot at the moment it doesn't have any fancy pot in it right now, but i will be switching it for a nice ALPS one soon.
Shunt Pot Volume Control - World-Designs-Forum
Very good read, i run a passive pot at the moment it doesn't have any fancy pot in it right now, but i will be switching it for a nice ALPS one soon.
34r to 10r is a mighty big jump.
Try adding a third 68r to get ~23r, then a fourth 68r to get ~17r, before trying 10r and before jumping to an extra 240% of current/dissipation.
Can the transformer cope with that amount of continuous current demand?
i found shunt pots much better in sound compared to conventional use. in my preamp i shunt for balance and volume with a series resistor of exactly 4,2kOhm, zerro temperature
sensitivity over a wide range and better then 0.01% tolerance specially made for me i israel. i tried all kind of things and got a great sound with a bourns conductive plastic but that had poor tracking and i could not put the mechanical angle of the pot in any convinient position, there was always too much gain al low settings. to give the controls a conventional feel cost me 3 weeks of hard mathematics and experimenting and i found a satisfying solution. i seem to prefer conductive plastic over cermet. the cermet sounded too hot for my tase. maybe it simply has more precission and i was not able to tame it. the blue alps did very well and to my surprise two coincidentely choosen samples had better tracking then 0.3 over a 40dB range. i find that sufficient because i do not listen extremly soft often on my primary system. i do that sometimes in car on a boring autobahn. by the way i found the TKD superiour but quite expensive and they did not have the correct values i need.
sensitivity over a wide range and better then 0.01% tolerance specially made for me i israel. i tried all kind of things and got a great sound with a bourns conductive plastic but that had poor tracking and i could not put the mechanical angle of the pot in any convinient position, there was always too much gain al low settings. to give the controls a conventional feel cost me 3 weeks of hard mathematics and experimenting and i found a satisfying solution. i seem to prefer conductive plastic over cermet. the cermet sounded too hot for my tase. maybe it simply has more precission and i was not able to tame it. the blue alps did very well and to my surprise two coincidentely choosen samples had better tracking then 0.3 over a 40dB range. i find that sufficient because i do not listen extremly soft often on my primary system. i do that sometimes in car on a boring autobahn. by the way i found the TKD superiour but quite expensive and they did not have the correct values i need.
AndrewT: transformer will be 120VA per winding (15V secondaries)
But as you suggest, this gradual reduction is a good way to go I think. Helps the learning process too.
Salas: I think I have some small section coax, so I will certainly try that. So, just use the centre conductor for signal and the shield for ground, or use 3 runs (for signal L, R and GND) and then tie all 3 shields to GND?
Fran
But as you suggest, this gradual reduction is a good way to go I think. Helps the learning process too.
Salas: I think I have some small section coax, so I will certainly try that. So, just use the centre conductor for signal and the shield for ground, or use 3 runs (for signal L, R and GND) and then tie all 3 shields to GND?
Fran
Your welcome Jleaman.
Joachim i too find shunt pots sound better then conventional pots...and im also using my alps blue with 0.01% z-foils from Israel...but i think what Salas is saying, is that the trade off for a good quality resistor means higher impedance and in the b1 buffer this is not suited. But as i have not tried just a normal 20k pot in the b1 buffer i really cant say. Im thinking of compromising between the two and putting in a 20k alps shunted with 18k resistors.
Joachim i too find shunt pots sound better then conventional pots...and im also using my alps blue with 0.01% z-foils from Israel...but i think what Salas is saying, is that the trade off for a good quality resistor means higher impedance and in the b1 buffer this is not suited. But as i have not tried just a normal 20k pot in the b1 buffer i really cant say. Im thinking of compromising between the two and putting in a 20k alps shunted with 18k resistors.
Fran,
I have some slick looking PTFE 29-30ga coax wire if you want to try that, can send you some.
Ooooh, nice. Well tell you what, let me have a look in my cables box first. I have this huge box, it looks like a bag of snakes with all sorts of wire in there!! I know theres an oddball cable in there with 7 coax leads terminated with BNC connectors. If they are coax, I'll at least try those first - hopefully I get to try that tonight.
My transformers are stuck in customs, even though they come from within the
EU ho-hum.
Fran
My transformers are stuck in customs, even though they come from within the
EU ho-hum.Fran
Centre for signal L, shield to ground, then another one for R, shield to ground again. Its a simple experiment for just one input. You can do fast A/B with another input.
Cant get my copy of this project finished...
Bought 100 yellow leds from THE LEDSHOPPE (China) waited 2.5 weeks for their arrival. The description claimed 1.8 volts FV typical...Turns out ALL 100 leds were within 2% or better of 1.95volts. Will send to Mouser for new batch. DIY is not always easy!!!
Bought 100 yellow leds from THE LEDSHOPPE (China) waited 2.5 weeks for their arrival. The description claimed 1.8 volts FV typical...Turns out ALL 100 leds were within 2% or better of 1.95volts. Will send to Mouser for new batch. DIY is not always easy!!!Banned
Joined 2002
Cant get my copy of this project finished...
Mistake was buying them from china
Its a good rig the one you used so to check Vf at enough mA, as they will work on the real boards.
Just use 4 of them 1.95V and in a Led position put 2 little diodes (1N4004) in series instead then. 1.95X4=7.8+DiodeDropX2+Vbe=about 10V. Those diodes are checked once by a member and measured very low noise.
Just tie the 2 diodes on air and insert them as a single component in one of the led positions. There are solutions so not to wait and wait.
See the picture, and don't forget, in the negative reg cathodes are facing the other way around.
Just use 4 of them 1.95V and in a Led position put 2 little diodes (1N4004) in series instead then. 1.95X4=7.8+DiodeDropX2+Vbe=about 10V. Those diodes are checked once by a member and measured very low noise.
Just tie the 2 diodes on air and insert them as a single component in one of the led positions. There are solutions so not to wait and wait.
See the picture, and don't forget, in the negative reg cathodes are facing the other way around.
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