Transistors out of stock?
Hi X
Just lurked around in your store and saw that the matched bd560 are out of stock...
Will you restock them?
I am finishing a dcb1, and will need a fine pre for the f4 wich is next in the line... (so it will take quite some time before I get to a preamp, but—I‘m „scouting“(?)
Thank you
David
Hi X
Just lurked around in your store and saw that the matched bd560 are out of stock...
Will you restock them?
I am finishing a dcb1, and will need a fine pre for the f4 wich is next in the line... (so it will take quite some time before I get to a preamp, but—I‘m „scouting“(?)
Thank you
David
I have matched BC557's - they will work fine instead of BC560's (same family). Send me PM if you want them.
If anyone in Oz needs an Aksa Lender PCB, let me know as there is a spare board set being held by a member already there with and extra set. It will save on shipping costs and time.
So to clarify, if anyone in Australia is interested in getting an Aksa Lender boardset with TH daughter boards, a set is already in Australia and I can arrange for purchase at same cost $45 plus cost of shipping domestically within Australia. That would probably save some time and cost vs shipping a set the US. I don’t know what domestic postage for a 5oz package is in Australia, but probably less than the typical $24 cost to ship from US.
Background on this: a member here on DIYA ordered a board set and it never arrived after 60days of waiting. I sent a replacement board set free of charge and that arrived like in 2 weeks or so. After about 3 months in mail limbo, the lost package arrives. The member could have just kept it but he graciously offered to send it domestically to someone else in Australia who would like one.
Background on this: a member here on DIYA ordered a board set and it never arrived after 60days of waiting. I sent a replacement board set free of charge and that arrived like in 2 weeks or so. After about 3 months in mail limbo, the lost package arrives. The member could have just kept it but he graciously offered to send it domestically to someone else in Australia who would like one.
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Hi X, local Australian from my city has PM'ed you regarding the A-L boardset in your last post.
Cheers
Julian
Cheers
Julian
I'm no expert about these things, so I hope this question is not too stupid.
The BOM cites the TKD 2CP601-10K as the pot of choice.
I'd like to use the Allo ladder style of pot with switched resistors.
Can someone confirm that would be the 10K version?
If a DACT CT-2 ( serial resistance ) were used, that would be a 20K version?
The BOM cites the TKD 2CP601-10K as the pot of choice.
I'd like to use the Allo ladder style of pot with switched resistors.
Can someone confirm that would be the 10K version?
If a DACT CT-2 ( serial resistance ) were used, that would be a 20K version?
Any pot from 10k to 50k can work here. The 10k pot just picks up less noise but higher value ones should be fine.
Hi X,
Can you check, the schematic on post No 1 may not work as shown. IMHO, the base of the MOSFET needs to be biased from the positive rail, OR a p-type mosfet has to be used to make the circuit work. That's what Eagle simulation throws up.
I guess you must have made the appropriate change on your PCB. Can you please update the schematic also.
Thanks.
Can you check, the schematic on post No 1 may not work as shown. IMHO, the base of the MOSFET needs to be biased from the positive rail, OR a p-type mosfet has to be used to make the circuit work. That's what Eagle simulation throws up.
I guess you must have made the appropriate change on your PCB. Can you please update the schematic also.
Thanks.
Hi Sanjeev,
This circuit is fully tested and has been built by dozens (maybe more, I have lost track) of people and it works as designed.
On the main board the first MOSFET cap multiplier is based on the design I got from Juma’s cap multiplier. There is only a positive rail as this is a single rail SE Class A design.
Schematic in Post 1 at top shows the BSP129 depletion mode MOSFET:
The production schematic in Post 1 is a depletion mode DN2540 MOSFET. It works opposite of an enhancement mode N-channel. Did you use a depletion mode like DN2540?
Here is production schematic for TH daughterboards:
This circuit is fully tested and has been built by dozens (maybe more, I have lost track) of people and it works as designed.
On the main board the first MOSFET cap multiplier is based on the design I got from Juma’s cap multiplier. There is only a positive rail as this is a single rail SE Class A design.
Schematic in Post 1 at top shows the BSP129 depletion mode MOSFET:
The production schematic in Post 1 is a depletion mode DN2540 MOSFET. It works opposite of an enhancement mode N-channel. Did you use a depletion mode like DN2540?
Here is production schematic for TH daughterboards:
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Are you referring to the Melbourne preamp? That is the dual rail version of the Aksa Lender.
https://www.diyaudio.com/forums/group-buys/333653-melbourne-daughterboard-m2x.html#post5690033
The Melbourne is one possible preamp daughterboard available for use in the Yarra preamplifier main board.
The YARRA Preamplifier/HPA for Melbourne DB Group Buy
https://www.diyaudio.com/forums/group-buys/333653-melbourne-daughterboard-m2x.html#post5690033
The Melbourne is one possible preamp daughterboard available for use in the Yarra preamplifier main board.
The YARRA Preamplifier/HPA for Melbourne DB Group Buy
I'm going to buy parts tonight (I hope) for a through hole version.
I see the spreadsheet AKSA-LENDER-X-MB_PL_04_01_2018 is not up to date.
As far as I can tell, there are three items that are different
1) Is 1N4001 good enough to replace V141 78-1N5250B ? or is 1N4002 better?
2) Is MPSA92 a good Sub for the now obsolete BC550C?
3) R141 should be 10K with same dissipation as the 220R in the BOM?
I want to fill the box I got for this project! Please let me know.
THANK YOU!
I see the spreadsheet AKSA-LENDER-X-MB_PL_04_01_2018 is not up to date.
As far as I can tell, there are three items that are different
1) Is 1N4001 good enough to replace V141 78-1N5250B ? or is 1N4002 better?
2) Is MPSA92 a good Sub for the now obsolete BC550C?
3) R141 should be 10K with same dissipation as the 220R in the BOM?
I want to fill the box I got for this project! Please let me know.
THANK YOU!
Cool to see more people building this preamp.
I don’t think there is a BC550 (that’s a NPN). There is a BC560 (PNP) on the LTP. The KSA992 is ideal but you will need to cross the legs to get it to work. You can also use 2N5401 and flip orientation 180deg. MPSA92 is a HV transistor. It’s not designed for small signals as gain is pretty low with Hfe only 25.
On the diode, it’s 1N400x, any will do. Even 1N4148 can work as it’s there to protect the MOSFET. Just make sure it’s not a zener. The R141 is usual 1/4w even 1/8w would work - same as 220R. Not much current t flowing here as this is the control side of the cap multiplier.
I don’t think there is a BC550 (that’s a NPN). There is a BC560 (PNP) on the LTP. The KSA992 is ideal but you will need to cross the legs to get it to work. You can also use 2N5401 and flip orientation 180deg. MPSA92 is a HV transistor. It’s not designed for small signals as gain is pretty low with Hfe only 25.
On the diode, it’s 1N400x, any will do. Even 1N4148 can work as it’s there to protect the MOSFET. Just make sure it’s not a zener. The R141 is usual 1/4w even 1/8w would work - same as 220R. Not much current t flowing here as this is the control side of the cap multiplier.
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