Aikido Phono 1+
This is a review and measurements of Aikido Phono 1+ preamplifier for MM phono cartridge. It was kindly sent to me by ASR member @Grotti . The preamplifier is based on circuit design with 6 discrete JFET transistors per channel. So I was curious how it would perform compared with now more usual designs with op-amps. The preamplifier is built into small, but rugged metal enclosure and the feeling is that it is very durable.
The front panel is simple, with product name and manufacturer's logo.
On the rear panel, there are RCA I/O connectors of 2 channels, 48 Vdc input power jack, ON-OFF switch and input impedance and input capacitance selector switches.
1. Specifications:
I could not find any datasheet, so I am copying data from hifi-wiki.com :
Manufacturer: Dipl.-Ing. H.-U. Otto
Model: Aikido Phono 1+
Made in: Germany
Plug-in power supply: 48 V / DC; 90 - 264 V, 50 Hz
Power consumption: 1.4 W
Dimensions: 128 x 48 x 85 mm (W x H x D)
New price: approx. 260, - EUR (as of: 2012)
Connections
Number of inputs: 1x phono in (RCA-Cinch)
Number of outputs: 1x Line out (RCA-Cinch)
Technical data:
Frequency response: 20 Hz - 25,000 Hz
input impedance: 1 kOhm / 47 kOhm / 100 kOhm
Input capacitance: 5 pF / 47 pF / 180 pF
Gain factor: 40 dB
Signal to noise ratio: > 88 dB
Distortion factor: < 0.1
RIAA deviation: < ± 0.15 dB
Remarks: Device is handmade
Can alternatively be operated with the battery power supply "Aikido Phono Akku".
hifi-wiki.com
2. Measurements
All the measurements done with 47k//47pF input impedance settings.
2.1. Output impedance
I started with measurements of output impedance, as the discrete topology indicated that it might be quite high. And yes, output impedance was measured as high 216 ohm. With my Cosmos ADC, the Aikido output voltage dropped of 2 dB and distortion was 3x higher, compared to high impedance input instrument results. So I had to put my low noise and low distortion unity gain Audio Buffer with 100 kohm input impedance between the Aikido and Cosmos ADC. The buffer's noise and distortion is absolutely negligible in comparison with Aikido's parameters. My recommendation is to use at least 10 kohm load impedance with the Aikido, or better higher. The higher, the better.
2.2. Frequency response
Frequency response measured is shown below:
The deviation from RIAA curve is +/- 0.2 dB (50Hz – 12.5kHz) and +0.5/-0.7dB (20Hz – 20kHz)
2.3. Channel matching
is excellent, with differences between channels below 0.05 dB.
2.4. Output noise and gain
Output noise with input terminated by 50 ohm was 43.47 uV over 22Hz – 22kHz band. Output noise with input terminated by Shure M35X cartridge was 92.22 uV over 22Hz – 22kHz band. This is a very good result, taking into account measured gain of 43dB/1kHz. For 5mV/1kHz input signal, this makes SNR = 82.94 dB with 50 ohm and SNR = 77.4 dB with Shure M35X. With M35X, the SNR result is better than for my Openamp with OPA627 op-amp of 0.5dB. SNR is calculated with respect to 5mV/1kHz input.
2.5. Distortion
Distortion of this preamp is not low. In a usual test from low impedance generator and 5mV/1kHz input signal, both THD and THD+N (SINAD) = 0.1% or -60 dB if you wish. This is completely defined by distortion component, as seen in the plot bellow.
The distortion spectrum contains only 2nd and 3rd harmonics and is very tube-like. This was probably designer's intention. Such distortion, however, will be inaudible due to intrinsic distortion of the vinyl record process.
THD+N vs. output voltage at 1kHz
3. Conclusion
Aikido Phono 1+ is a well engineered and reliably built MM phono preamp, with very low noise, higher distortion, good RIAA response and excellent channel matching. It is not cheap and not for everyone, but it may find its customers. It is necessary to take into account high output impedance of the simple output stage, which calls for load impedance >10 kohm, to keep acceptable level of distortion.
Link to hifi-wiki:
hifi-wiki.com
This is a review and measurements of Aikido Phono 1+ preamplifier for MM phono cartridge. It was kindly sent to me by ASR member @Grotti . The preamplifier is based on circuit design with 6 discrete JFET transistors per channel. So I was curious how it would perform compared with now more usual designs with op-amps. The preamplifier is built into small, but rugged metal enclosure and the feeling is that it is very durable.
The front panel is simple, with product name and manufacturer's logo.
On the rear panel, there are RCA I/O connectors of 2 channels, 48 Vdc input power jack, ON-OFF switch and input impedance and input capacitance selector switches.
1. Specifications:
I could not find any datasheet, so I am copying data from hifi-wiki.com :
Manufacturer: Dipl.-Ing. H.-U. Otto
Model: Aikido Phono 1+
Made in: Germany
Plug-in power supply: 48 V / DC; 90 - 264 V, 50 Hz
Power consumption: 1.4 W
Dimensions: 128 x 48 x 85 mm (W x H x D)
New price: approx. 260, - EUR (as of: 2012)
Connections
Number of inputs: 1x phono in (RCA-Cinch)
Number of outputs: 1x Line out (RCA-Cinch)
Technical data:
Frequency response: 20 Hz - 25,000 Hz
input impedance: 1 kOhm / 47 kOhm / 100 kOhm
Input capacitance: 5 pF / 47 pF / 180 pF
Gain factor: 40 dB
Signal to noise ratio: > 88 dB
Distortion factor: < 0.1
RIAA deviation: < ± 0.15 dB
Remarks: Device is handmade
Can alternatively be operated with the battery power supply "Aikido Phono Akku".
Aikido Phono 1+ | hifi-wiki.com
2. Measurements
All the measurements done with 47k//47pF input impedance settings.
2.1. Output impedance
I started with measurements of output impedance, as the discrete topology indicated that it might be quite high. And yes, output impedance was measured as high 216 ohm. With my Cosmos ADC, the Aikido output voltage dropped of 2 dB and distortion was 3x higher, compared to high impedance input instrument results. So I had to put my low noise and low distortion unity gain Audio Buffer with 100 kohm input impedance between the Aikido and Cosmos ADC. The buffer's noise and distortion is absolutely negligible in comparison with Aikido's parameters. My recommendation is to use at least 10 kohm load impedance with the Aikido, or better higher. The higher, the better.
2.2. Frequency response
Frequency response measured is shown below:
The deviation from RIAA curve is +/- 0.2 dB (50Hz – 12.5kHz) and +0.5/-0.7dB (20Hz – 20kHz)
2.3. Channel matching
is excellent, with differences between channels below 0.05 dB.
2.4. Output noise and gain
Output noise with input terminated by 50 ohm was 43.47 uV over 22Hz – 22kHz band. Output noise with input terminated by Shure M35X cartridge was 92.22 uV over 22Hz – 22kHz band. This is a very good result, taking into account measured gain of 43dB/1kHz. For 5mV/1kHz input signal, this makes SNR = 82.94 dB with 50 ohm and SNR = 77.4 dB with Shure M35X. With M35X, the SNR result is better than for my Openamp with OPA627 op-amp of 0.5dB. SNR is calculated with respect to 5mV/1kHz input.
2.5. Distortion
Distortion of this preamp is not low. In a usual test from low impedance generator and 5mV/1kHz input signal, both THD and THD+N (SINAD) = 0.1% or -60 dB if you wish. This is completely defined by distortion component, as seen in the plot bellow.
The distortion spectrum contains only 2nd and 3rd harmonics and is very tube-like. This was probably designer's intention. Such distortion, however, will be inaudible due to intrinsic distortion of the vinyl record process.
THD+N vs. output voltage at 1kHz
3. Conclusion
Aikido Phono 1+ is a well engineered and reliably built MM phono preamp, with very low noise, higher distortion, good RIAA response and excellent channel matching. It is not cheap and not for everyone, but it may find its customers. It is necessary to take into account high output impedance of the simple output stage, which calls for load impedance >10 kohm, to keep acceptable level of distortion.
Link to hifi-wiki:
Aikido Phono 1+ | hifi-wiki.com
Last edited:
. I know about the Japanese origin.
