still4given said:
Hi Terry,
The PCBs have been ordered should be to me in a couple weeks. We are now taking pre-orders for the attenuator now, and yes we will be making available a complete kit with resistors and all. We are even considering a small trafo for the attenuator.
I want it as bad as you do. 🙂 I want the smaller PCB than my self etched version.
Cheers!
russ
One note, for balanced use you would order the controller + relay PCB kit plus one additonal relay PCB kit. For SE use you just need the controller + relay kit.
Cheers!
Russ
Cheers!
Russ
Russ White said:
I definitely want the option for balanced in/out. That is one of the things that interested me in the first place.
I looked at your website and don't see where you are taking pre-orders. Care to share?
Thanks, Terry
You just click on the "order page" link in the product page.
Here is the direct URL:
http://twistedpearaudio.com/ordering.html
Here is the direct URL:
http://twistedpearaudio.com/ordering.html
I am about to change the ordering options (same prices) if you guys want to hold off a sec. shoudl be easier to figure out what you need.
[EDIT] Done. There are now options for SE Kit and Balanced Kit, as well as relay board kit if you want more than 2. Also added a trafo option, which will be a 7VA Amveco with dual 7V outputs. In parrl it will deliver 1A. You can use any source up to 12-14V, as long as it delivers enough current for your relay board setup.
[EDIT] Done. There are now options for SE Kit and Balanced Kit, as well as relay board kit if you want more than 2. Also added a trafo option, which will be a 7VA Amveco with dual 7V outputs. In parrl it will deliver 1A. You can use any source up to 12-14V, as long as it delivers enough current for your relay board setup.
AR2 said:
Hello,
I am a bit afraid to speak for Kari, as I don't know exactly what his final circuit or PCB turned out to be. But I do know this if the values for the resistors are then same as mine in all other respects, then it should be fine for a positive rail of 60V up to around 80V. For the negative rail 9V seems very low to me(actually I have tried it that low and did not like it), and with the trafo you have I would go for at least 18VDC on the negative rail. For that a value of R5 of 2K to 10K should work just great. I would probably try 4.7K if I were you.
Cheers!
Russ
BrianDonegan said:
The PE transformer has a third set of secondary wires that put out 14VAC. Is this too high? Is there a way to reduce it?
Thanks, Terry
still4given said:
No, thats not too high at all, in fact it would work just fine. 🙂 It will need to be able to handle at least 350ma for the controller and two relays PCBs.
Cheers!
Russ
Thank you Russ. So thats mean that I do not need to change any zeners, just resistor. Do you have any suggestion how to change positive rail voltage from 60 to 70V? My transformer gives 55V in output.
55VAC ~ 77VDC. I have 7 9.1V zeners at the positive side and that gives me around 64V without load and 60V with load. If you want 70V out just make sure that the zeners end up with 70V + 4V that you loose on the fet.
For the negative you also need to think about the resistor that sets the bias. I = U / R, 20V/27R = 740mA = 320mA trough each side which sounds a bit too much. On the other hand if you have enough heatsinking that would work.
/Kari
For the negative you also need to think about the resistor that sets the bias. I = U / R, 20V/27R = 740mA = 320mA trough each side which sounds a bit too much. On the other hand if you have enough heatsinking that would work.
/Kari
AR2 said:
I use a single 75V zener on my PS for the positive rail which gets me close to 75V out. Keep in mind the zeners have a tolerance factor (1% - 5% or whatever) so thats very close to what I would expect.
Thank you Kari and Russ. This was a good point, and I do not think that small heatsink that is attached (on Kari's boards) will provide enough cooling. They are already way too warm.Kari said:
I just realized that I maybe hijacking this tread that is not about Kari's XBosoz and I apologize if that is the case.
Kari said:
Hi Kari,
First thanks for joining the discussion it is very much appreciated.
You make a good point. On my preamp the HS barely get warm though, so I am leaving the bias where it is. Perhaps the high bias is one reaon why it sounds so good!! 🙂
If people find their HS getting too warm (not likely unless you use a small HS) you could adjust R8 up a bit. Maybe 47R.
The only things now that get warm for me are the four power resistors (R1,R2.R6, and R7).
Cheers!
Russ
From what i have read here, the higher the bias the better they sound 🙂 But don't up it too much, you might saturate the fet.Russ White said:
Better yet, put in a let's say a 50R pot and you'd have a variable bias adjuster. That way you could adjust it for the "perfect" sound 🙂
/Kari
Russ White said:
Hi Russ,
Do you have the BOM for these so I might see if I can save any money by sourcing the parts myself? I'm sure your price for the complete kit is reasonable but I'm not prepared to lay out that much more right now. I've got a lot of irons in the fire right now.
Blessings, Terry
Absoluetly Terry, Brian will be posting a BOM on the site soon. The kits aren't cheap, but that is mostly due to the high quality relays which are used, which unfortunately cannot be had very cheaply. They are around $3 each (actually a bit more in small qty), and you need 14 of them for balanced attenuation, plus resistors, conectors, IDC headers, cable, etc...
I am goinf to need 2 set of balanced volume controls.
I also need 2 sets of input selectors.
Should I wait and order everything later or should I preorder the attenuators first?
I also need 2 sets of input selectors.
Should I wait and order everything later or should I preorder the attenuators first?