Check polarity of the inputs/outputs from 8pins connector to your amp. One row is GND and othe row is signal. If you drive signal input to GND the sound will be very soft. Likewise if you drive outputs with GND from Preamp sound is very soft.
Your bias seems ok and gain of 10x should be plenty loud.
One way to check if Preamp is working stand-alone is to connect cheap $1 earbud headphones (free from airlines) to outputs of the Preamp. Polarity won’t matter as its isolated and if it plays loudly, Preamp is good.
Your bias seems ok and gain of 10x should be plenty loud.
One way to check if Preamp is working stand-alone is to connect cheap $1 earbud headphones (free from airlines) to outputs of the Preamp. Polarity won’t matter as its isolated and if it plays loudly, Preamp is good.
It would be nice if someone who has completed this pre would give us a nice review.
Check out post #572 by drpro. I'd give my own but I still have a few projects to finish before I can integrate this pre into a full system and give any meaningful review.
Check out post #572 by drpro. I'd give my own but I still have a few projects to finish before I can integrate this pre into a full system and give any meaningful review.
Thank you. I have read it, was just trying to get some more people to speak up. You blew my cover....😀
Haha! No worries ggetzoff. For what it's worth, I have used it in conjunction with a minidsp and a couple of different amps on an experimental open baffle speaker. So far, the sound has been great. Very full and detailed. Once I get my dual 3FE25 mini karls and ACA built and move everything into the dining room I'll get a better sense of imaging and soundstage. Stay tuned!
I think Vunce has a review somewhere as well. JPS64 said he could stop listening to it a few pages back 🙂
It would be nice if someone who has completed this pre would give us a nice review.
My review will not be as eloquently written like Drpro’s was, but I’ll throw in a few of my thoughts.
Right from the start this preamp has been extremely quiet, no noises of any kind are added when using this pre. I feed it 24v-44v depending on the daughter board/amplifier combo being used and always a black/silent background.
This leads me right to one of my favorite features about this preamp, the ability to swap out the DB’s for different situations required. Currently, I’m mainly flipping between my Alpha20 and Big MoFo amplifiers. They represent a huge difference in preamp requirements. Voila!! Install the “customized” DB’s for either amplifier and you have one preamp that’s a perfect match to both amplifiers 🙂
How it sounds is very subjective because everyone uses different associated gear, unique room setups and styles of listening. So, I’m not going to go overboard here, but, two aspects continue to amaze me: a huge soundstage and an incredible amount of articulate low frequency detail. I’ll be passing through my living room and have stop in my tracks because I heard something different in a song I’ve heard 100 times before!
I feel the AKSA Lender Pre is going to stay in my main system for a long time.😀
Thanks for the thoughtful review Vunce. I meant to say JPS64 said he couldn’t stop listening to it. He has a tube amp and full range Saba Greencones.
What current does this Preamp draw?
As a Preamp bias is about 25mA to 35mA per channel. As HPA it’s 100mA per channel.
My review will not be as eloquently written like Drpro’s was, but I’ll throw in a few of my thoughts.
Right from the start this preamp has been extremely quiet, no noises of any kind are added when using this pre. I feed it 24v-44v depending on the daughter board/amplifier combo being used and always a black/silent background.
This leads me right to one of my favorite features about this preamp, the ability to swap out the DB’s for different situations required. Currently, I’m mainly flipping between my Alpha20 and Big MoFo amplifiers. They represent a huge difference in preamp requirements. Voila!! Install the “customized” DB’s for either amplifier and you have one preamp that’s a perfect match to both amplifiers 🙂
How it sounds is very subjective because everyone uses different associated gear, unique room setups and styles of listening. So, I’m not going to go overboard here, but, two aspects continue to amaze me: a huge soundstage and an incredible amount of articulate low frequency detail. I’ll be passing through my living room and have stop in my tracks because I heard something different in a song I’ve heard 100 times before!
I feel the AKSA Lender Pre is going to stay in my main system for a long time.😀
Vunce,
That's great, thanks for doing that! Yes, of course there are lots of factors: source, speakers, amps, room, cables, ect., then you add a computer and it gets even more complicated. Anyway, I appreciate the the review.
Cheers,
Greg
Is that @120v?
mA bias current at whatever the Vcc is set at (24v to 48v).
I don‘t want to miss it in my setup!
I‘m still waiting for transistors to finish KORG B1 Clone.
I‘m finishing ACA, MoFo, M2 and F6; don‘t forget ALPHA.
I‘m working on a SIT preamplifier using Russian transistors.
FAOW in the pipeline.
SissySIT in the pipeline.
I‘ll report!
PS: no PC, simply Shanling M2 perhaps later DSC2?!
JP
I‘m still waiting for transistors to finish KORG B1 Clone.
I‘m finishing ACA, MoFo, M2 and F6; don‘t forget ALPHA.
I‘m working on a SIT preamplifier using Russian transistors.
FAOW in the pipeline.
SissySIT in the pipeline.
I‘ll report!
PS: no PC, simply Shanling M2 perhaps later DSC2?!
JP
mA bias current at whatever the Vcc is set at (24v to 48v).
Ok. I misunderstood his question then...
I was curious regarding total consumption since I read that smps that’s too oversized might be a bad thing...
As a Preamp bias is about 25mA to 35mA per channel. As HPA it’s 100mA per channel.
Thanks X.
Yes, I meant DC, as I was trying to establish whether the boost converter that Twocents is using is able to supply enough juice. Turns out it is plenty beefy at 2A max rating - which I tested and verified yesterday.
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Twocents:
I had one daughterboard (TH) that I could not get working. Spent 5hrs debugging to no avail. I simply had to abandon it and make a new one in less than an hour. The new one worked fine upon first startup. Sometimes the problems are elusive indeed. I can send you a new pair of TH boards in the paper mail as a letter if you want - no charge. Should get there quickly.
I had one daughterboard (TH) that I could not get working. Spent 5hrs debugging to no avail. I simply had to abandon it and make a new one in less than an hour. The new one worked fine upon first startup. Sometimes the problems are elusive indeed. I can send you a new pair of TH boards in the paper mail as a letter if you want - no charge. Should get there quickly.
Twocents:
I had one daughterboard (TH) that I could not get working. Spent 5hrs debugging to no avail. I simply had to abandon it and make a new one in less than an hour. The new one worked fine upon first startup. Sometimes the problems are elusive indeed. I can send you a new pair of TH boards in the paper mail as a letter if you want - no charge. Should get there quickly.
Well thank you very much X, you are always willing to walk the extra mile! I might take you up on that. Still cannot trace the problem, but I have not given up yet. The problem is duplicated as I built the daughter boards in parallel. I also have two other options - wait for Skylar to populate his daughter boards and test them in my setup, and/or get components and populate my SMT daughter boards. I will get there ...

The BOM calls for C5 to be a mica cap. (Mouser 598-CD15ED330JO3F)
How would a ceramic cap fare there?
This one: CERAMIC DISC CAPACITOR, 33pF, 500V
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How would a ceramic cap fare there?
This one: CERAMIC DISC CAPACITOR, 33pF, 500V
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I'm trying to troubleshoot Twocents' build, by checking and measuring the components (prior to populating my own boards). We have exactly the same components, because we bought together. The 33pF ceramic cap is the only item that I'm unsure of, since it deviates from the BOM by not being a mica cap.
Here is a close-up of one of his daughterboards, showing the ceramic cap.
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Here is a close-up of one of his daughterboards, showing the ceramic cap.
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