vdi_nenna said:Are the PEC pots dented? Dented...is that the word I'm looking for?Notched?
They aren't stepped. They are an old fashioned potentiometer with a strip of carbon and a wiper. Albeit Mil Spec. Whatever that means! I guess rugged with good quality components.
However, from what I've gathered here actually sound pretty good and the look like the pots used in First Watt B1. Maybe a good reference to start with.
Can you provide a link to those "coolest attenuators"
Since all my amps (not yet finished) are diy, I can use what ever I want to connect the pre and power amp together.
I know Nelson used RCA plugs, Naim like to use DIN plugs.
I was thinking of using something from Neutrik.
What is best type of connection and cable to connect the two together?
I know Nelson used RCA plugs, Naim like to use DIN plugs.
I was thinking of using something from Neutrik.
What is best type of connection and cable to connect the two together?
At work we use type N connectors and plugs.
http://en.wikipedia.org/wiki/N_connector
Would these be appropriate for audio use?
http://en.wikipedia.org/wiki/N_connector
Would these be appropriate for audio use?
b-1 attenuators
sorry about that oneday
this is the site-check it out some great stuff-very reasonably priced
http://glass-ware.stores.yahoo.net/newhardware.html
enjoy
rob
sorry about that oneday
this is the site-check it out some great stuff-very reasonably priced
http://glass-ware.stores.yahoo.net/newhardware.html
enjoy
rob
thanh1973 said:
Best connector = no connector (soldered)
Best length cable is usually the shortest cable possible. Type? ask 20 people and get 20 different answers.
Since it is DIY, you can entertain hard wired output with your favorite cable (on the linstage output), with plugs on the amp end.
Only reason not to use good quality RCA is if you run balanced, then use XLR.
You don't need uwave connectors here, but if you wanted to try some, I would entertain trying SMA, as there are lots of cheap premade teflon SMA cables available used. It would be my first preference for digital over bnc, provided you can handle converting the transmission line to 50 ohm. If DIY, no problem.
Bob
thanh1973 said:
Um, those N are kinda klunky and big. Sorta old fashioned actually. I would not *over think* this.
Kimber PBJ teflon from the linestage to a decent quality RCA is probably a good place to start. I'm dating myself, don't know if they even sell this anymore. Perhaps a hand woven braided silver cable in teflon insulation is another idea as an upgrade.
Yes, eliminate un-needed connectors whenever possible. Just like extra gain stages, and capacitors. I'm searching for an emotican here
Those massive old fashioned N connectors are sorta Will Rodgers, and not current thinking. Today smaller dia. = better for high frequency test instruments. For 20 GHz use APC 3.5, for 40 GHz use APC 2.4, etc. But frankly, we are not really needing 20GHz for this job, are we?
Bob
BFNY said:
Wow, I haven't heard Kimber PBJ's mentioned in years. I remember them from the Stereophile Recommended Component lists. Always wanted to give them a try but never did. If you can find some, or make some, they'd do a good job.
Belden makes some nice shielded microphone cable that you can use to roll your own interconnects.
For interconnect cable Steve @ Apex.jr has some shielded twisted pair that works great.
Silver plated Tef#$n insulated twisted pair in a braided shield wrapped in tef#$n.
Not expensive, VERY easy to solder and handy.
He also has co-ax. Silver plated Tef#$n insulated.
I used to use the PBJ and liked it but moved and had a military radio tower close by so I switched to the "shielded" version.. No reviewers liked it but I didn't mind it. Sonically it was almost identical to the PBJ.
Silver plated Tef#$n insulated twisted pair in a braided shield wrapped in tef#$n.
Not expensive, VERY easy to solder and handy.
He also has co-ax. Silver plated Tef#$n insulated.
I used to use the PBJ and liked it but moved and had a military radio tower close by so I switched to the "shielded" version.. No reviewers liked it but I didn't mind it. Sonically it was almost identical to the PBJ.
b-1 with a R-2R-distortion
I have just finished putting my R-2R in an old DH101 cabinet with a B-1-such fun
I have the ability to measure harmonic distortion(an old liberty audiosuite) and am having trouble with the R-2R- when it is in the signal path for input switching and volume control. It is introducing some serious 2nd harmonic distortion- re 10x @ 30hz, and 4-5x @90hz, 180hs, 240hz and a general rising trend of harmonic distortion as the frequency ascends. I am using a star ground scheme and spent alot of time last night lifting grounds, moving them to and from the chassis, and putting resistors in the various ground legs to try to lessen the distorion. My leads from the inputs are 24g silver over copper teflon coated alpha core wire with an external braid shield with a return wire from the braid back to the ground point . My lowest distortion came from a 25k ohm resistor between the input ground wire and the star ground. I also used 100k ohm between shield wire to chassis ground - saw some improvement but that 30hz spike( the B-1 was reading.04% distortion @ 30hz by itself but wtih the R-2R in line it rose to about .8%) really has me wondering. It would seem to be power supply related but I saw no difference when I first moved the switching power supply module away from the preamp and then changed the powersupply to a linear supply-makes me think its in the board not the supply- I even cut in some inductors and caps in the power line and saw no appreciable difference-can anyone recomend a cap between the 5v input and ground on the board- has anyone else seen, worked through this kind of issue?
all input(pardon the pun) would be appreciated
rob
I have just finished putting my R-2R in an old DH101 cabinet with a B-1-such fun
I have the ability to measure harmonic distortion(an old liberty audiosuite) and am having trouble with the R-2R- when it is in the signal path for input switching and volume control. It is introducing some serious 2nd harmonic distortion- re 10x @ 30hz, and 4-5x @90hz, 180hs, 240hz and a general rising trend of harmonic distortion as the frequency ascends. I am using a star ground scheme and spent alot of time last night lifting grounds, moving them to and from the chassis, and putting resistors in the various ground legs to try to lessen the distorion. My leads from the inputs are 24g silver over copper teflon coated alpha core wire with an external braid shield with a return wire from the braid back to the ground point . My lowest distortion came from a 25k ohm resistor between the input ground wire and the star ground. I also used 100k ohm between shield wire to chassis ground - saw some improvement but that 30hz spike( the B-1 was reading.04% distortion @ 30hz by itself but wtih the R-2R in line it rose to about .8%) really has me wondering. It would seem to be power supply related but I saw no difference when I first moved the switching power supply module away from the preamp and then changed the powersupply to a linear supply-makes me think its in the board not the supply- I even cut in some inductors and caps in the power line and saw no appreciable difference-can anyone recomend a cap between the 5v input and ground on the board- has anyone else seen, worked through this kind of issue?
all input(pardon the pun) would be appreciated
rob
marc brown said:
Guess they are still going strong.
http://www.kimber.com/Products/Interconnects/PBJ/PBJ.aspx
Many audio parts places sell the same cable without terminations, as unbraided Kimber TCSS and quad braided TCSS-GQ (Michael Percy, Handmade Electronics)
For less critical cables, I also use twisted or braided CAT5 tefl0n
DH Labs BL-1 is also a good fully shielded interconnect cable.