Because your average diyer has a back log of about 20 years of projects.
Ha, so very true, at least in my case.
Hi all, I'm about to order the PCB's and start looking for parts.... Haven't read every post yet but is there a current BOM somewhere ? What about the daughter boards, I saw a coupe of posts about ordering these. Can we order these pre populated with SMD?
Thanks, sure a few more questions to come...
Thanks, sure a few more questions to come...
I think you might want to read post #1 in the GB thread. Most of your questions about BOM etc will be there. There may even be a “shopping cart” from Digikey or Mouser. There are two SMD boards. One for miniMELF resistors (hard to find) and one for 0805 / 1206 chip resistors. The TH is the popular favorite though.
AKSA's Lender Preamp with 40Vpp Ouput GB
I could probably offer populated SMT daughterboards if enough interest.
Welcome aboard Nzlowie,
Check out the GB starting thread, there is tons of useful information(diagrams, Boms, schematics).
The AKSA Lender pre is an excellent sounding, versatile preamp.
Regards,
Vunce
AKSA's Lender Preamp with 40Vpp Ouput GB
WOOPS!! You beat me to it X
Check out the GB starting thread, there is tons of useful information(diagrams, Boms, schematics).
The AKSA Lender pre is an excellent sounding, versatile preamp.
Regards,
Vunce
AKSA's Lender Preamp with 40Vpp Ouput GB
WOOPS!! You beat me to it X
X, just to clarify on this post - are you saying that the 10uF (C123, C133) caps should rather be film caps?
Finally got around to finishing the soldering on my AKSA Lender Preamp. What hit me immediately is the big soundstage and the presence of instruments in the music I was listening to. Previously I was using my friend's Marantz 1060 as my Preamp. I now realize how the 1060 is showing its age. Thank you Hugh and XRK for the first and best Preamp I have ever built or owned.
As a follow up. I'm using the Toshiba 2SA1837's with the resistor changes at R14 and R15 as discussed in post #554. I also have 3.9k carbon comp at R10 for the time being. I may swap out different types and values at R10 over time to see what I like best. The input caps are 4.7uF Russian K73-16 PETP capacitors. I read that they are a great, neutral cap for the money. I bought 10 of each at 1, 2.2, 4.7, and 10uF on eBay so I could have a range of caps to work with on future projects. As far as I can tell they sound great!
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Thanks Vunce! Yes, I definitely had to mock up the cap placement with the DB's before soldering. I didn't want to have to hide those Nichicon KZ's on the bottom, but it's a small price to pay for great sound from a great preamp.
I have to say the Toshibas, even with the heat sinks, get pretty darn hot. Almost too hot to touch. I'm running 24v straight off an SMPS.
I have to say the Toshibas, even with the heat sinks, get pretty darn hot. Almost too hot to touch. I'm running 24v straight off an SMPS.
Great to hear. Very encouraging. Thank you for the close-up photos – it helps nervous novices like me.the first and best Preamp I have ever built or owned.
Are you running at 24V? I was assuming the input voltage should be around 50 – 52V? And I am also planning on using Toshiba 2SA1837s – now you have me slightly concerned.
I have the Toshiba’s also and am curious as to how they sound. But, I have to reconfigure the capacitors on the MB to make room for better heatsinks on the DB’s.
Yep Twocents, from the discussions about the 2SA1837's I gathered one of the major changes is lowering the supply voltage. X, feel free to chime in if I'm doing anything wrong in this regard.
Vunce, I'm also thinking bigger heatsinks are in order for the 2SA's. I just clipped an additional silver heat sink on each one this morning and it seems to have helped a lot already. Let me know if you had a heat sink picked out. Curious to know what you were thinking of using.
Jwarch,
Fantastic build - super looking Preamp. The 2SA1837 mod with resistors change was for using double duty as a headphone amp. The bias current is about 100mA at 24v supply with 12v drop across each active is 1.2w dissipation. You might try these, I recently got some and meant to try.
577202B00000G: Aavid Thermalloy : Heat Sink Passive TO-220 24.4degC/W Black Anodized : Fans & Cooling
At 24C/W that’s about 30C rise for 1.2w so 50C total so should be fine.
@twocents, if you want to drive a MoFo or F4 at high voltage swing stick with the lower bias current and KSA1381 and 48v supply.
Fantastic build - super looking Preamp. The 2SA1837 mod with resistors change was for using double duty as a headphone amp. The bias current is about 100mA at 24v supply with 12v drop across each active is 1.2w dissipation. You might try these, I recently got some and meant to try.
577202B00000G: Aavid Thermalloy : Heat Sink Passive TO-220 24.4degC/W Black Anodized : Fans & Cooling
At 24C/W that’s about 30C rise for 1.2w so 50C total so should be fine.
@twocents, if you want to drive a MoFo or F4 at high voltage swing stick with the lower bias current and KSA1381 and 48v supply.
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I just tried out those stamped sheet aluminum heatsinks (doubled up) and they work well. I am using thermal grease between the two back-to-back heatsinks and between the transistor and heatsink. Temperature was 84C before with older C-channel heatsink, and now is 67C, still hot but I don't think the transistor cares at that temp.
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