Well done Drpro🙂
Now you can sit back, listen and enjoy!!
What capacitors are you using in C124,126,134,136?
Now you can sit back, listen and enjoy!!
What capacitors are you using in C124,126,134,136?
Here is a nice precut case - very reasonably priced. It may not be tall enough though but might be good for similar projects.
Look what I found on AliExpresshttp://s.aliexpress.com/NbIzI7Zn
Look what I found on AliExpresshttp://s.aliexpress.com/NbIzI7Zn
I put my Aksa Lender pre fitted with Toshiba 2SA1837 vs KSA1381 and running 80mA bias. Wow there is a very noticeable improvement in sound quality when driving a power amp and speakers. The spatial imaging is improved and upper treble clarity. More dynamic and controlled. Definitely a worthwhile upgrade to consider. The 2SA1837, is arguably the finest audio BJT ever made so doesn’t surprise me how good it sounds.
Note that pins of 2SA1837 are reversed so it needs to fit from backside of PCB. But that works well as heatsink has more space.
Note that pins of 2SA1837 are reversed so it needs to fit from backside of PCB. But that works well as heatsink has more space.
Sounds like an inexpensive improvement X. Thanks for this info. What value change to the bias resistor do you recommend?
Thanks
David
Thanks
David
It’s in this post on GB thread. Need to drop Vcc to 24v though to manage heat output. Headphones don’t need huge swing. I have not tried 2SA1837 at lower bias and higher voltage yet.
http://www.diyaudio.com/forums/grou...der-preamp-40vpp-ouput-gb-28.html#post5311833
So first thing to try is swapping KSA1381 for 2SA1837 leave everything the same. Then try changing R15 to 22ohms and R14 to 4.7ohms. That should double bias from previous.
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I bought the very last 100 from Mouser. 🙂
They are beautiful devices and not too expensive.
I’m glad that they are still available. They make wonderful drivers for big amp projects or preamps/headphone amps.
folks at Dbent.com are going to arrive at work tomorrow and wonder why the sudden number of orders for 2SA1837 devices!!
X,
What size SMD resistor will fit the pads for the MELFs?
I'm finally buying parts to build this pre-amp and am trying to figure out the spacing.
Thanks!
What size SMD resistor will fit the pads for the MELFs?
I'm finally buying parts to build this pre-amp and am trying to figure out the spacing.
Thanks!
Also planning and compiling my bom for this build. Just some (stupid) questions:
1. For power – rather than using a laptop brick and DC step-up, I am looking at using a small smps like the Meanwell EPS-45-48 (48V 1A). Will that be ok? And is the CLC filter then recommended?
2. To set appropriate gain for a lowish gain amp like the ACA, the recommended value for R10 (on daughter board) is 6k8. Is it advisable that this should be a carbon resistor as shown in the schematic?
1. For power – rather than using a laptop brick and DC step-up, I am looking at using a small smps like the Meanwell EPS-45-48 (48V 1A). Will that be ok? And is the CLC filter then recommended?
2. To set appropriate gain for a lowish gain amp like the ACA, the recommended value for R10 (on daughter board) is 6k8. Is it advisable that this should be a carbon resistor as shown in the schematic?