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Aikido Phono 1+ MM preamp review
- Thread starter pma
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- Aug 18, 2020
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Disappointing ENOB! Obviously a measurement artefact - according to this, you could rip records with an 8 bit DAC!
It's well-known. While not comparable to dBFS (these test signals are ≈RMS level of a normal recording, or for Elipson test record "-24 dB", whatever standard is used...), best SNR at 3.54 cm/s is around -40 dB when I use mono-coupling below 150 Hz. Signals peaks can be 20 dB higher though.
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- Thread Starter
- #26
Yes, it strongly depends on distortion recorded to vinyl and on vinyl surface noise and not only on cartridge distortion. Depending on phase of distortion components, there also might be some suppression or addition in their measured level. It is in fact impossible to make exact comparisons with this media. Rather some fun 
.
.- Thread Starter
- #27
Listening test
@Grotti , I have recorded the same song (from B. Springsteen) with 2 settings of input capacitance, 47pF and 180pF. You (and anyone who is interested) may download it from:
Aikido_test.zip
drive.google.com
There are those two versions in the zip file. So you may listen and tell me. Of course foobar ABX result would be the best proof.
Deltawave seems to indicate that the difference would be inaudible.
View attachment 428835 View attachment 428836 View attachment 428837
Well, with concentrated listening, there seems to be a slight difference that is quite reliably distinguishable in the ABX test and corresponds to FR differences with 47pF and 180pF load capacitance position. Below the ABX report.
Code:
foo_abx 2.1 report
foobar2000 v2.0
2025-02-15 19:14:15
File A: Aikido_47pF.wav
SHA1: 4ab47f7f7bc880df33ada484789dced10c589395
File B: Aikido_180pF.wav
SHA1: b7deb8d07f0cfd64d314442a6677bea71b20e1ff
Output:
WASAPI (shared) : Speakers (Realtek High Definition Audio)
Crossfading: NO
19:14:15 : Test started.
19:16:22 : 01/01
19:16:45 : 02/02
19:17:04 : 03/03
19:17:13 : 04/04
19:17:22 : 05/05
19:17:34 : 06/06
19:17:49 : 07/07
19:18:01 : 08/08
19:18:12 : 09/09
19:18:20 : 10/10
19:18:27 : 11/11
19:18:42 : 12/12
19:19:00 : 13/13
19:19:11 : 13/14
19:19:19 : 14/15
19:19:28 : 15/16
19:19:28 : Test finished.
----------
Total: 15/16
p-value: 0.0003 (0.03%)
-- signature --
681bfc285b2dd8aab2cdc94878ab96952969d12eThese are the cumulated spectra:
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As a Japanese, I personally feel somewhat strange as well as not-suitable upon looking reading and pronouncing the Japanese word "Aikido" as their brand name; this is just same feeling of mine for the brand name "MAMORITAI" as I pointed here and here.
"Aikido" is a Japanese noun "合気道", pronunciation [aikiꜜdoː], which is one of the modern martial art parties/schools; you would please find Wikipedia page on "Aikido" here. We Japanese usually recognize "Aikido" as one of Proper nouns since it is one of the existing martial art schools.
Is using a Japanese word for brand-name and/or product-name of audio gears a kind of trend or fashion in audio market?
If this would be the case, they are encouraged to consult with native Japanese people prior to decide the brand-name/product-name.
One of the acceptable and feel-alright cases would be product naming of "Satori" for a SP driver (by SB Acoustics, ref. here and here) which is a Japanese Buddhist term "悟り", Wiki here.
Doubly odd as Aikido has for decades been associated with a tube circuit from Glassware.
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- Thread Starter
- #31
Exactly! Same observation here.
- Thread Starter
- #33
Post #4.
7.14 Vrms/1kHz output divided by 43dB gain (141.25x) = 50.55 mVrms.
However, at 10kHz, it clips at 260mVrms input. Isn't it excellent, @Newman ? The reason is the Aikido topology. First JFET gain stage, then JFET buffer, then passive RIAA EQ, then second JFET gain stage, then JFET output buffer.
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- Thread Starter
- #35
I will not measure on the PCB solder points. From simulation, it is 300 - 350 mV(rms). Clipping is "soft" as it is usual for the simplest gain stages with NFB only at the emitter resistor.
restorer-john
Grand Contributor
@Newman with a 48V (+/-24v split on the board?) supply, the "input" clipping is going to be pretty high. If you want to test for 'overload' at various parts of a complete circuit, just buy one and knock yourself out. Stick your probes in and report back, we'll all be waiting for your insight....
- Thread Starter
- #39
No, it is an "old school" single supply discrete design with coupling output capacitor. Classic JFET common source gain stages (with source resistors to reduce gain) and Borbely JFET buffers. Tube design schol.
lini
Member
Otto's Aikido is supposed to be a solid state variant thereof, so it's not that odd. And in fact he also mentions, that it's an established design by John Broskie, in the product descriptions for his Aikido variants (see for example there: https://www.ebay.de/itm/297006697175).
Over here Otto's Aikidos are pretty popular, btw. I haven't yet had or heard one myself, though.
Greetings from Munich!
Manfred / lini
edit: missing bracket added
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