Hi Do,
So your question is there a 0dB gain power amp that’s Class AB, not Class A?
That’s an interesting question. I think take your favorite Class AB amp, remove the front end and VAS stage and put the Aksa Lender input to it. I have lots of discrete Class AB that could try this with. But why? The whole reason is to drive 0dB SE Class A output stages that don’t have any global feedback and the smooth no-crossover distortion characteristics that lacks high order harmonics. I have an Apex FX-8 Class AB that uses lateral FETs for the output so it will be inherently stable and less prone to thermal runaway. I might see if that can be rejiggered to bypass the input LTP and VAS and just apply the Aksa Lender to the output. Fnny, but I have taken that same amp and removed the output stage to make a slick +/-40V preamp.
Just setting the Aksa Lender with PCA daughterboards on low gain, say 12dB and driving a conventional Class AB LM3886 chipamp actually sounds very nice. It’s sort of an analog sound processor that forces the amp to be dominant second order distortion.
Here is just such a system - just an inexpensive $40 stereo LM3886 with built in PSU and DC protection relay - just added a 250VA 25v trafo.
This is the PCA daughterboard:
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My friend connected it to his mofo but he’s getting one channel with really bad noise. I don’t know what it is since I’m not there. However, the preamp works perfectly with headphones and measure perfectly on both channels. Probably something from the selector board? I’ll check with him and see if we can troubleshoot this remotely.
Otherwise, sounds really good with headphones!
Do
Otherwise, sounds really good with headphones!
Do
Try swapping the RCA out and see if the noise persists in the same channel. Make sure that each side has a proper ground - that is, ground is not left floating.
I know that the selector board on the Yarra has isolated left and right channel grounds, so if you only connect ground on one side but not the other, it may leave a floating ground which picks up noise. I don't know if this is a problem on the Aksa Lender, but worth a try to look and see.
I know that the selector board on the Yarra has isolated left and right channel grounds, so if you only connect ground on one side but not the other, it may leave a floating ground which picks up noise. I don't know if this is a problem on the Aksa Lender, but worth a try to look and see.
Here's my own AKSA Lender Preamp
I'm using a Sigma 22 but leaving the ground floating, so it is set to ~+/-26Vdc but using only + and - I'm getting a little over 52Vdc. I've added a 1W 25 turn 10K trimmer on it to precisely set the voltage.
Next step will be to add it to a chassis once I can get stuff from China.
Do
I'm using a Sigma 22 but leaving the ground floating, so it is set to ~+/-26Vdc but using only + and - I'm getting a little over 52Vdc. I've added a 1W 25 turn 10K trimmer on it to precisely set the voltage.
Next step will be to add it to a chassis once I can get stuff from China.
Do
This begins to look like a convention of users of boutique condensers
I had never seen capacitors that connect like this, in the middle. More info about them?
I don't think that is the capacitors but a copper foil connected to gnd.
Yes, exactly
I did this since the CDE 940C are quite big and not being in a grounded chassis it grabs RFI when having my hands close to them. So adding a copper foil connected to ground shields the cap very good. I know there's a way to find which leg is connected to outer foil and this leg should be on the load side but using a copper foil fixes my thing for now.
Thanks
Do
With the additional foil in place, try measure the capacitance from it to each axial leg, should indicate which leg is connected to the outer foil layer.
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Hi Do,
Any progress on getting your Aksa Lender all buttoned up? How is it playing for you sound wise?
Getting stuff from China seems to take about an extra week nowadays. I wipe down my boxes and all items received in the mail with bleach spray before brining it in the house.
Stay healthy and safe! (this is for everyone)
Cheers,
X
Hi X,
The MoFo has been completed last night in a single home made chassis (wood and metal) to give it a vintage look (will post pictures later on). I'm still waiting for my chassis for the AKSA Lender. The seller has a my money and a warning that he's on vacation... I will most likely ask for a refund with Paypal.
Still, they're connected to my system and playing music on a set of test speakers as burn in for about 100 hours. I've peaked into the room for about 30 minutes and listen to a few songs. This stuff is playing really good! I'm impressed so far.
Thanks
Do
BTW, I didn't get a reply from you on email I sent you a couple weeks ago, did you receive it?
The MoFo has been completed last night in a single home made chassis (wood and metal) to give it a vintage look (will post pictures later on). I'm still waiting for my chassis for the AKSA Lender. The seller has a my money and a warning that he's on vacation... I will most likely ask for a refund with Paypal.
Still, they're connected to my system and playing music on a set of test speakers as burn in for about 100 hours. I've peaked into the room for about 30 minutes and listen to a few songs. This stuff is playing really good! I'm impressed so far.
Thanks
Do
BTW, I didn't get a reply from you on email I sent you a couple weeks ago, did you receive it?