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AKSA's Lender Preamp with 40Vpp Output
AKSA's Lender Preamp with 40Vpp Output
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Old 26th October 2018, 04:32 PM   #871
Skylar88 is offline Skylar88  South Africa
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I'm thinking to replace the carbon pots on my freshly built AKSA Lender preamp with Cermet pots. This was decided after reading Hugh's FAQ's.

If I want to "law fake" a linear Cermet pot with a simple 15 KOhm resistor, should I start out with a 100K pot as described in the FAQ's? Will this work on the AKSA Lender Pre or should I start with a different value pot?
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Old 26th October 2018, 11:20 PM   #872
xrk971 is online now xrk971  United States
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AKSA's Lender Preamp with 40Vpp Output
Skylar,
One thing to do is to listen for a while, maybe a week or two and listen for negative effects of your pots on sonic quality. One quick test is to put pots on max, thereby effectively bypassing them and use your DAC output (via software or knob on DAC) as volume control. Then set DAC at some reasonable near max output (80%) and use pot on preamp as volume control. Can you hear degraded sound vs setting of max volume?

I use Alps stereo linear 10k pots from RK09 series (circa $5ea). They have nicely machined aluminum shaft. They use carbon tracks on polymer substrate (I know because I accidentally popped one open by pushing a volume knob onto the shaft with too much force). They sound very good to me, but I am not a volume pot aficionado.

You will find that this preamp is smooth and has no scratchy sound when adjusting the pot. The RK09 seems to be well balanced left and right too.
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Old 27th October 2018, 12:57 PM   #873
Skylar88 is offline Skylar88  South Africa
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Thanks X, I did the quick test that you've suggested. I used 50%, 80% and then full pot travel, with the media player adjusted for the same volume on all three settings.

For my playlist I chose simple tracks like Katie Melua - I'd Love To Kill You, Nicolaj Grandjean - Heroes & Saints, and Craig Chaquico - Gypsy Nights. I could not hear any distortion or other nasties. They sound superb on all three settings with an amazing soundstage, exceptional imaging and good layering. What a preamp!

Thanks Jerry, for coercing my into building it.

I've already ordered Bourns Series 91 Cermet pots with metal shafts, so I'm anyway going to replace these Alpha (Taiwan) pots and keep them for a future project.
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Old 27th October 2018, 04:04 PM   #874
xrk971 is online now xrk971  United States
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AKSA's Lender Preamp with 40Vpp Output
Well it sounds like your Alpha Taiwan pots are decent quality. I know budget $0.25 pots can sound terrible. But I have heard people say the best pot is no pot! for me though, a $5 to $10 seems to be good enough.
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Old 4th November 2018, 01:34 AM   #875
xrk971 is online now xrk971  United States
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AKSA's Lender Preamp with 40Vpp Output
I know several people are busy at work on the Aksa Lender Preamp. Please post progress photos!
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Old 4th November 2018, 04:18 AM   #876
zman01 is offline zman01  Bangladesh
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AKSA's Lender Preamp with 40Vpp Output
Here you go with one - work on the PCBs is nearly done.

But (dreaded) chassis work, connectors etc still have to do...
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File Type: jpg AKSA Lender preamp nearly done diyA upload.jpg (292.0 KB, 249 views)
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Old 4th November 2018, 04:53 AM   #877
nzlowie is offline nzlowie  Australia
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Components should be arriving any day now..... Just need to check the forum for any changes / corrections since I ordered the parts. If nothing, I'll make a start next weekend.
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I know several people are busy at work on the Aksa Lender Preamp. Please post progress photos!
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Old 4th November 2018, 05:16 AM   #878
xrk971 is online now xrk971  United States
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Nice work Zman. I usually try to test it on the bench before putting it in a case. It makes debugging a lot easier. I would at least power it up and check to make sure bias current on daughterboards are good.
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Old 4th November 2018, 05:19 AM   #879
zman01 is offline zman01  Bangladesh
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AKSA's Lender Preamp with 40Vpp Output
Quote:
Originally Posted by xrk971 View Post
Nice work Zman. I usually try to test it on the bench before putting it in a case. It makes debugging a lot easier. I would at least power it up and check to make sure bias current on daughterboards are good.
Of Course X, planning to proceed in that way only.
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Old 7th November 2018, 09:57 AM   #880
maty tinman is offline maty tinman  Spain
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Default H2 predominance test

I think you should to do this test:

Do you like tube distortion? - listening test

Click the image to open in full size.
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