Hi. Nine members left only to either send me their contact info and/or make the payment. For those who paid I sent the complete doc.
Schematic. If you look at the B1 schematic you may see some parts extra from the original NP article. It seems there is already three versions of this circuit, the original FW article, the Christmas Gift version and an other one. I combined some element of the Christams version with the original.
We will have to decide what resistor values to use, the original ones or the Christmas version. It may not be such a big deal. Any way for example if you don't want to use the 100R resistors on the JFET drain, simply replace them with a short...
SB
Schematic. If you look at the B1 schematic you may see some parts extra from the original NP article. It seems there is already three versions of this circuit, the original FW article, the Christmas Gift version and an other one. I combined some element of the Christams version with the original.
We will have to decide what resistor values to use, the original ones or the Christmas version. It may not be such a big deal. Any way for example if you don't want to use the 100R resistors on the JFET drain, simply replace them with a short...
SB
Thanks for the BOM and Schematic.
With regard to the DC converter, I've personally chosen the IRM-20-24.
It comes in the same package style and pinout but it has a slightly higher output ripple max (200mA p-p vs 180mA p-p). Though because it is not 'Medical Patient Contact Device' rated, it costs a little less ($12 vs $20AUD). Not a huge deal, but every little helps when the BOM is approaching $200AUD!
YMMV etc.
With regard to the DC converter, I've personally chosen the IRM-20-24.
It comes in the same package style and pinout but it has a slightly higher output ripple max (200mA p-p vs 180mA p-p). Though because it is not 'Medical Patient Contact Device' rated, it costs a little less ($12 vs $20AUD). Not a huge deal, but every little helps when the BOM is approaching $200AUD!
YMMV etc.
Great choice indeed, there is so much filtering after the AC/DC converter that this small change in ripple won't mean much at the supply output. Thanks for the tip.
Still wating for the contact/payment from:
shattered_dream
stijn001
DontHertzMe
randytsuch
Atom666
valley711
Tubo
Please mention your Diyaudio nickname with the PayPal payment. It makes tracking order easier for me.
For those that made the payment, you should all have received payment confirmation and documentation. It was sent to the email address that you provided. If not received let me know, I'll resend the package.
Thanks
SB
Still wating for the contact/payment from:
shattered_dream
stijn001
DontHertzMe
randytsuch
Atom666
valley711
Tubo
Please mention your Diyaudio nickname with the PayPal payment. It makes tracking order easier for me.
For those that made the payment, you should all have received payment confirmation and documentation. It was sent to the email address that you provided. If not received let me know, I'll resend the package.
Thanks
SB
Question here:
Q100-Q104 JFET, 2SK370 or 170-GR, N-CH, Matched TO92 Toshiba Ebay 8
Are these to be matched in pairs, in quads, or all 8? It gets expensive quickly!!!
LSK170 can be had at very affordable prices, but what would be the right number to increase the chances of having good matches for a matched pair, a quad and 8, respectively. also when using LSK170, which grade is the best? I have a few D, but understand that B is better, at least for the ACA, I don't know if grade B is universally the best one for Pass' designs...
Q100-Q104 JFET, 2SK370 or 170-GR, N-CH, Matched TO92 Toshiba Ebay 8
Are these to be matched in pairs, in quads, or all 8? It gets expensive quickly!!!
LSK170 can be had at very affordable prices, but what would be the right number to increase the chances of having good matches for a matched pair, a quad and 8, respectively. also when using LSK170, which grade is the best? I have a few D, but understand that B is better, at least for the ACA, I don't know if grade B is universally the best one for Pass' designs...
According to a member that participated in the B1 XMAS Group, JFET included were K170-GR grade, matched at 4.7ma
I completed the Gerber, with extensive checks
and I'll place the order tomorrow.
Here the PCB mechanical check into the recommended Hammond enclosure, it works perfectly
Absolute capacitor height inside this enclosure is 40mm
I still miss contact and payment from four GB members, and I started to receive request for a standby list.
The names are:
DontHertzMe, Tubo: no reply
shattered_dream, valley711: Contact ok, but no payment after payment request...
Take note that once I receive the PCB, I'll wait a week, and then will give your requested pcb to the ones on the waiting list.
By the time I receive the PCB + 1 week, we are talking probably 3-4 weeks. So if after all this time you don't reply, I think I would had waited for long enough.
So please contact me. A GB like this is a lot of work, and there is no point for my to get stuck with a lot of unsold pcb.
Thanks for your understanding
SB
I completed the Gerber, with extensive checks
and I'll place the order tomorrow.Here the PCB mechanical check into the recommended Hammond enclosure, it works perfectly
Absolute capacitor height inside this enclosure is 40mm
I still miss contact and payment from four GB members, and I started to receive request for a standby list.
The names are:
DontHertzMe, Tubo: no reply
shattered_dream, valley711: Contact ok, but no payment after payment request...
Take note that once I receive the PCB, I'll wait a week, and then will give your requested pcb to the ones on the waiting list.
By the time I receive the PCB + 1 week, we are talking probably 3-4 weeks. So if after all this time you don't reply, I think I would had waited for long enough.
So please contact me. A GB like this is a lot of work, and there is no point for my to get stuck with a lot of unsold pcb.
Thanks for your understanding
SB
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Hmmm, diyaudio kits come with Fairchild j113 and two options on the board to solder 2sk170, LSK170, 2sk370 OR J113 which has a different pinout. IT would-be be nice in “our” boards have this option too. Do you think that would-be still be possible Algar-emi? Am I right that when using J113 a resistor value changes? (R1 in the original Pass scheme?)
For me J113 is a serious option because it is easily available over here.
For me J113 is a serious option because it is easily available over here.
Thanks! I'm afraad my tecknical knowledge is not enough to answer your question.
I found out NP uses j113 in this document:
http://www.firstwatt.com/pdf/art_diy_nutube_preamp.pdf
Quote from that document:
Q1 and Q2 transistors are selected for specific Idss values, and the R1 values are matched to the Q2 Jfets. For J113 parts, the Idss of Q1 is set to be equal to current through Q2, and with the 2SK parts it is matched and the value of R1 is zero. The kits are provided with selected J113's, and note that Q1/Q2 are not interchangeable. The use of the other parts involves matched Idss values ranging from about 4 to 8 mA.
I found out NP uses j113 in this document:
http://www.firstwatt.com/pdf/art_diy_nutube_preamp.pdf
Quote from that document:
Q1 and Q2 transistors are selected for specific Idss values, and the R1 values are matched to the Q2 Jfets. For J113 parts, the Idss of Q1 is set to be equal to current through Q2, and with the 2SK parts it is matched and the value of R1 is zero. The kits are provided with selected J113's, and note that Q1/Q2 are not interchangeable. The use of the other parts involves matched Idss values ranging from about 4 to 8 mA.
