Bakoon Products EQA-5640mk4 Phono Equalizer Amplifier

The EQA-5640mk4 is a phono equalizer amplifier that enables more accurate playback of vintage analog discs. Until the 1950s, records had a mixture of various equalizer curves in addition to the RIAA curve, which is the current standard equalizer curve. Each record company had its own standards for the production of master tapes, and each record company had its own equalizer curve. Currently, the Recording Industry Association of America = RIAA has unified the equalizer curve. Of course, most phono equalizer amps on the market are also RIAA-compatible, so when you listen to old records from the mid-1950s or earlier, you are listening to a completely different setting. The EQA-5640mk4 is an equalizer amplifier equipped with 6 types of curves: NAB, COLUMBIA, FFRR, AES, and old RCA, which are currently standard RIAA and typical old equalizer curves. By using these six types of equalizer curves, you can enjoy the latest records and vintage discs in your collection with their original sound.

When switching the equalizer curve, the gain of 1 KHz is designed so that the fluctuation is within 0.3 dB even if the EQ is switched, so it is convenient when switching the curve and checking the change in sound. By muting, noise can be suppressed when switching between selectors, replacing cartridges, and cleaning needle tips. There is also no loop noise in the power amplifier connection.

Low noise, high resolution

The EQA-5640MK4 uses the HBK(I) and HBFBC of the new-generation SATRI circuit to achieve a good signal-to-noise ratio and almost no noise or distortion.

In addition to switching between MM and MC cartridges, you can obtain the optimal position without clipping by setting the gain of the equalizer in 6 steps according to the output voltage of the cartridge. Use HIGH1 for MC cartridges with very small output voltages, and LOW2 for high-output MM cartridges with output voltages greater than 10 mV.




In addition, the output circuit is equipped with conventional voltage output and current output SATRI-LINK. As a result, the output impedance is several tens of M ohms, and by insulating the connection between the company's preamplifier and the power amplifier, induced noise is not picked up even if the cable is extended for a long time, making it possible to play high-dimensional analog records.

The power supply is an analog power supply, using a high-quality large-capacity toroidal transformer in a shielded case, and all surface-mounted components produce a direct sound without thick coloring in the midrange. The size is the same as the SCA-7511mk4, a compact amplifier size.

input	1 system, MM and MC cartridges can be switched with a switch.
output	1 voltage output, 1 SATRI-LINK output (can be used simultaneously)
EQ Curve	RIAA, NAB, COLUMBIA, FFRR, AES, OLD RCA
gain	HIGH1, HIGH2, MID1, MID2, LOW1, LOW2
Frequency response	20Hz~50kHz
Maximum Output	8V (1% distortion)
DISTORTION RATE (1KHZ)	4V: 0.06%
SNR	-135dB(HIGH1)
EQ Error	±0.3dB
size	70mm(H) x 236mm(W) x 293mm(D)

*Bakun Products will gradually change its logo and name to SCL (SATRI Circuit Laboratory). Thank you for your understanding.

Speaking of multi-curve phono equalizers, there is the CAP-1004 of the CAP series recently, but the EQA-5640MK4 supports multi-EQ curves, and changing the basic internal configuration from the SATRI-IC of the MK3 era to a newly developed circuit that is almost the same as the CAP1004 seems to be a substantial downgrade, so it is a little disappointing ( In the first place, the sound of Bakun, which is the subject of comparison, is surprisingly high-dimensional, so I don't have to worry about the sound quality). Rather, if you are mainly listening to vintage records from the 1960s or earlier, being able to listen to the original sound in time with the equalizer curve of the record will be far more advantageous than listening to the sound with the curve off. The analog power supply of the toroidal transformer stabilizes the voltage and gives the impression that it is thicker or richer around the midrange than the CAP1004. The gain can be set in 6 steps, which is compatible with recent high-power cartridges. With MK3, it's only natural that the MUTE relay, which was unpopular because it was broken, has already been well prepared.
The function of the multi-curve, which is important, is that in the old days, the equalizer curve was different depending on the record company and the era in which it was recorded, and some of the recording formats were not listed, so it is not easy to do depending on the record, but when it is matched, the sound changes surprisingly and it is a tear-jerker, and the joy is also a joy. Also, it is interesting that DECCA still used FFRR in the 1960s, even though it should have been unified into the RIAA around 1953~54, and the equalizer curve that other record companies used before even after adopting the RIAA, has a much better sound extension. This will be the best item that will take you to a new exploration of the old analog records in your collection.