AKSA's Lender Preamp with 40Vpp Output

dr.loudness Gillian Welch - Soul Journey

DR10

I do not think they are better than the famous Chinese DACT.

I have the older iFI iCAN headphones amp with the green RK09 and I do not like the potentiometer.

[Old image, link] http://maty.galeon.com/WP-imagenes/...EF-Q100-ATL-Hi-Fi-DC-Ripple-Blocker-x4-ME.jpg

iCAN SE

unnamed-9.jpg


At low levels the green RK9 does not work very well, there is an imbalance, which is a known problem.

Btw, it sounds better under the 3 mm galvanized steel sheet. The aluminum case must have thin walls, very thin. 1-2 mm, insufficient for atmospheric RF / EMI I have at home. A case with 1 mm steel sheet is better idea and cheaper.
 
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The cheap DACT type attenuator finally arrived today. Sounds a bit better than the ALPS Potentiometer. Have them set so can swap them easy to test them.

Still waiting for the Mundorf Caps. Might add some caps (10u0, C1022,C1032) while waiting. If I run the volume up, the sound is crackling!!!


Ive been using those cheap DACT style from EBay for over 10 years and they are really good. Not just for money, just good.
 
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Joined 2012
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dr.loudness Gillian Welch - Soul Journey

DR10

I do not think they are better than the famous Chinese DACT.

I have the older iFI iCAN headphones amp with the green RK09 and I do not like the potentiometer.

[Old image, link] http://maty.galeon.com/WP-imagenes/...EF-Q100-ATL-Hi-Fi-DC-Ripple-Blocker-x4-ME.jpg

iCAN SE

unnamed-9.jpg


At low levels the green RK9 does not work very well, there is an imbalance, which is a known problem.

Btw, it sounds better under the 3 mm galvanized steel sheet. The aluminum case must have thin walls, very thin. 1-2 mm, insufficient for atmospheric RF / EMI I have at home. A case with 1 mm steel sheet is better idea and cheaper.

That looks like it may be a fake Alps RK09. The aluminum is discolored and dull and I believe they are machined shafts with a flat (in general). I use them all the time and have no issues with imbalance that is noticeable. They are quite smooth and quiet. I suppose the makethem in knurled shafts too but most of the ones I have seen are machined with a flat:

s-l300.jpg
 
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Thanks for the info of the dr.loudness-war.info Never heard about that before.

So DR10 for the Soul Journey. Not in the higher values but not terrible. Sounds good here.

I decided to move to the DACT attenuator after reading about it in here and several other posts in diyAudio. Any members with it say they are very good. I don't know if other ALPS are as good or better, haven't ever had any type ALPS before to compare them.
 
Started listening to some of my CD's. I'm amazed by some of them.

Many years ago, I bought a CD called "Same Mother, different father; by Ocaso" Made in 1998 in Melbourne Australia. Don't know if the CD is still available now. Runs two nylon string guitars and the third was doing Latin percussion. Can clearly hear each of the items and the direction of each of them. Never heard them like that before on any of the previous systems. Amazing!

The system now sounds way better than any version of system we have had and changed items since I started building an amp and speakers in around 1975.

Currently, the system is:
--> AKSA Lender Preamp
--> PASS Class A, single stereo Amp
--> Rotel RCD-965BX (around 1990 but good)
--> Topping D50 DAC
--> Rogers LS7 speakers (also around 1990)
 
Rogers LS7t

:mail:Rogers LS7t loudspeaker Measurements | Stereophile.com

As can be seen from the plot of impedance amplitude and phase (fig.4), the LS7t represents an easy load for an amplifier to drive, staying above 8 ohms over nearly all the audio band. The port tuning can be seen at 40Hz.

666RLS7fig4.jpg



Rogers LS7t loudspeaker Specifications | Stereophile.com

Description: Two-way, reflex-loaded, stand-mounted loudspeaker.

Drive-units: 1" titanium-dome tweeter, 8" polypropylene-cone woofer.

Crossover frequency: 3kHz. Crossover slopes: third-order, 18dB/octave. Frequency response: 55Hz–22kHz –2dB. Sensitivity: 88dB/W/m.

Nominal impedance: 8 ohms. Amplifier requirements: 15W minimum.
Imagine the sound with very good recordings and high/very high DR. Well, I think you will not need to imagine it :mail:
 
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Well, in 2001, new model.

Musical Fidelity A1

-> [PDF] https://www.studio-22.com/musical_fidelity/manuales/a1_int_3.pdf

Voltage, RMS 17V
Voltage, Peak-to-peak 48V
Power 36W
Current peak-to-peak 22.8A
Damping factor 142
Output devices per channel 2
Pre-out impedance 47 ohms

THD + N, 20Hz to 20 kHz <0.02%
Signal / noise ratio -94dB A-wtd
Input sensitivity for full power 120mV
Input impedance 43K ohms
Overload margin 37dB
Channel separation >52dB
Frequency response 20Hz to 20kHz +0,-0.3dB
 
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If you want to enjoy a very good recording with high/very high DR with these speakers (88 dB/W/m) you will need more than 8 watts.

Something like this very old recording, but the sound is incredible. It seems they are in your room or you in the jazz club.

Ahmad Jamal - Ahmad's Blues (1959), CD, Chess 1994, Germany

DR Peak RMS Duration Track
--------------------------------------------------------------------------------
DR15 -0.10 dB -18.20 dB 4:06 01-Ahmad's Blues
DR14 -0.10 dB -16.46 dB 4:16 02-It Could Happen To You
DR17 -0.10 dB -20.56 dB 3:46 03-I Wish I Knew
DR15 0.00 dB -18.78 dB 7:40 04-Autumn Leaves
DR12 -0.91 dB -16.10 dB 4:16 05-Stompin' At The Savoy
DR16 -0.10 dB -19.51 dB 4:47 06-Cheek To Cheek
DR19 -0.10 dB -22.62 dB 3:26 07-The Girl Next Door
DR17 -0.10 dB -19.88 dB 3:52 08-Secret Love
DR15 -0.10 dB -17.92 dB 2:19 09-Squatty Roo
DR16 -0.50 dB -18.37 dB 4:02 10-Taboo
DR16 -0.10 dB -23.25 dB 3:18 11-Autumn In New York
DR17 -0.10 dB -19.43 dB 4:44 12-A Gal In Calico
DR17 -3.06 dB -24.40 dB 2:38 13-That's All
DR15 -0.10 dB -18.54 dB 3:40 14-Should I?
DR17 0.00 dB -20.67 dB 3:12 15-Seleritus
DR13 -0.90 dB -16.19 dB 5:07 16-Let's Fall In Love
--------------------------------------------------------------------------------

Number of tracks: 16
Official DR value: DR16
 
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Another Aksa Lender completed

Feeling very pleased with myself. Just been listening to this preamp through my ACA 1.6 and Linn Keilidhs. After an initial hiccup which was traced back to a failed IRF610 all is now working fine.

Changes to the original BOM include the use of some Clarity Cap SA 10uF on the output which are paralleled with 0u1F. The SA caps are ridiculously big for the space on the PCB but were left over from a previous project and saved me the price of a pair of Wima 10uF (that's close to £20 in the UK). I also used a cheap stepped attenuator from eBay.

It sounds excellent so far. I am amazed how much extra bass extension is being produced from this set-up. I have been using a Naim 32.5 for many years so my ears are very much accustomed to its bandwidth limiting. The noise floor is extremely low and it is very happy playing at loud volume without sounding strained. I shall have to give it a few days to get used to the sound as the mid and treble seem less pronounced compared to the Naim, which I feel may be due to the relatively extended bass of the Aksa Lender and the forward presentation of the Naim. Has anyone else experienced this?

Thank you to everyone involved in creating this wonderful preamp, I am going to have lots of fun plugging this in to various systems once it’s in a case.
 
Linn Keilidh

[PDF] http://docs.linn.co.uk/wiki/images/0/01/Keilidh_user_manual.pdf
Type: 2 way loudspeaker with crossover at 2.8kHz

Frequency response: 50Hz - 20kHz +/-2dB, 1m on axis

Input impedance: 4 Ohms nominal

Amplifier requirements: At least 60W per channel into 4 Ohms. For example, Linn LK140

Features: Internal adjustment of treble level.

Wiring options: Single-wiring, Bi-Wiring, Bi-amplification, Active Bi-Amplification, Active Tri-Amplification.

Size: 825mm (H) x 200mm (W) x 275mm (D)

Weight: 18kg each
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I have had Keilidhs for about 5 years now and can cheerfully say the following. Power requirement: I have had two amplifiers each of 65 w per channel and both are capable of pushing the Kelidhs to quite reasonable (unreasonable for the neighbours!) volumes. The important part of the equation is the Keilidh's 4 ohm impedence which dictates that your amplifier needs to be able to push fairly serious amounts of current to be able to drive them properly. All that being said, I don't think that I would consider an amp of below 35 watts per channel for use with them.
 
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I knew of the Keilidh's reputation for needing lots of watts. The ACA is sitting in place of a NAP160 (80W p/c into 4ohms). It certainly won't drive the Linns to party volumes like the 160 but it does play loud and clean.

The Naim power amp has given me many years of pleasure and I originally only put the ACA in that system to see what it sounded like. The music that I am now hearing has encouraged me to build a second ACA and the Aksa Lender. An F5 turbo (50W) is about 30% completed so far and I'm starting to research an active crossover just to see what the Keilidhs would sound like driven that way.

I guess what I'm saying is that, while it isn't a perfect match for the Linns, the ACA is capable of producing a strong emotional response in this listener.
 
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