I posted a new layout. I moved the screened names so they aren't under other parts, and I have changed the 20mA current sources for 2mA cascoded current sources that run within their SOA.
634KiB PDF download
634KiB PDF download
anatech said:
I'm not a miracle worker. It will take me a few weeks to order all the parts and put it together.
Hi jwb,
I can wait for that report. Things take me a while these days too.
As far as cleaning amps is concerned, Imaclean and I have a lot in common. I usually make comments like that at work (& I'm not proud of it either, they just come out.
)
I can wait for that report. Things take me a while these days too.
As far as cleaning amps is concerned, Imaclean and I have a lot in common. I usually make comments like that at work (& I'm not proud of it either, they just come out.
)
I am frustrated in finding replacements for 2sk163 and 2sj44. 2sk170 and 2sj74 look like good substitutes, but I need to find them from a reliable supplier, and both in the BL grade.
I have a similar problem. Since the repair trade has been killed, parts distributors have "died" as well. I had a great guy who closed his doors 2 yrs ago. Still looking for a new RELIABLE distributor. Notice I didn't say cheap.
-Chris
-Chris
In the past, I have fiddled with making my own semiconductor devices. With the current situation it starts to sound like a reasonable thing to do!
Sounds more like we may go to custom devices from players like Motorola. Complete with wonderful house numbers.
It's too bad that the general market has no clue what good sound is, they just want to hear "boom" all around them. That and replace the "rig" every few years when some new processing comes out - cheap.
-Chris
It's too bad that the general market has no clue what good sound is, they just want to hear "boom" all around them. That and replace the "rig" every few years when some new processing comes out - cheap.
-Chris
Resistor noise tradeoff?
By reducing the DC current in the dual differential from 20mA to 2mA, I will presumably get a reduction in 1/f noise from that stage's resistors. But to keep the quiescent operating point, I also have to increase the resistors by a factor of 10, meaning more thermal noise. Is this an even trade? Or will I have more resistor noise? Or less?
I'm using Dale RN-60D resistors.
By reducing the DC current in the dual differential from 20mA to 2mA, I will presumably get a reduction in 1/f noise from that stage's resistors. But to keep the quiescent operating point, I also have to increase the resistors by a factor of 10, meaning more thermal noise. Is this an even trade? Or will I have more resistor noise? Or less?
I'm using Dale RN-60D resistors.
Here's the bill of materials I assembled for this design. The order quantities and extended price are for 4 channels.
Bill of Materials
Bill of Materials
Jfets
I have a source for many Japanese parts. JFETs too.
Email me with your wish list and I can figure out what is available at what prices... let me know if you need matched devices - extra.
Some are not available, but there may or may not be suitable subs - some with different packages, some not.
The more interest, if available, the better I can do.
Some devices I have some stock on now. Not all ranges (gr,bl, v etc.) may be available at any given point in time...
I have a number of 2SJ74s here in front of me... mostly GR, iirc.
When tested they range up and down IDSS in the category.
_-_-bear
I have a source for many Japanese parts. JFETs too.
Email me with your wish list and I can figure out what is available at what prices... let me know if you need matched devices - extra.
Some are not available, but there may or may not be suitable subs - some with different packages, some not.
The more interest, if available, the better I can do.
Some devices I have some stock on now. Not all ranges (gr,bl, v etc.) may be available at any given point in time...
I have a number of 2SJ74s here in front of me... mostly GR, iirc.
When tested they range up and down IDSS in the category.
_-_-bear
I finally found the perfect FET to replace those Supertex FETs: Zetex ZVP3310 and ZVN3310. I don't know why I didn't think of it before, they're very common, but I think I had the TO-220 stuck in my mind. There's no reason for that, since these components dissipate < 200mW in this circuit.
Zero Cool said:
Honestly I wish you did too ;-), you are a fine conniseur of the 250. Personnally I put it on auction to make a few bucks... saw the market getting heated up... ;-)
As I said I will sell the KSA-250 but keep my KAV-250 which is more revealing, I use B&W 801's with each. ;-)