Two months ago I received an offer from Mr.Carlos (BursonAudio) to test V5i discrete op-amps. At that moment I was looking for the perfect op-amp for my balance amplifier iBasso PB2 "Pelican". I can replace there four single pre-amps (the gain op-amps) and four single output op-amps (power op-amps).
The signal source I used was the balanced line output of the FiiO X7 player or iBasso DB2 balanced DAC output with Hidizs AP60-II player as USB transport.
When I got the op-amps from Burson Audio it were not V5i, but four V5-OPA-S pieces, which are higher grade than V5i. Packed very well, even plastic ties included to fix the op-amps in a horizontal position or upside down.
I have tested the different op-amps from the iBasso kit, but they do not impress me by the sound at all. So I bought the top op-amps from Sparkos and MUSES.
The supply voltage of the op-amps in the PB2 amplifier is +/-8V, but sparkos and muses can operates up to +/-18V. Therefore, I made the PB2 mod for powering it from external power supply with two 4S li-po batteries with total voltage near 30V. The high voltage supply for op-amps allow them to work in an optimal mode with minimal harmonic distortions and with higher slewrate.
In the V5-OPA-S specs, the maximum supply voltage is +/-15V, but they works OK on +/-16V supply voltage with minimal heating.
Of course, the size of the V5-OPA-S is not small at all, I think even the owners of some desktop setup will have problems with this op-amp installation. In my iBasso especially, the pads for op-amps are located on the board very close to each other and it was impossible to install it vertically in the board. So I had to make the extension board adapters.
The V5-OPA-S width is also so large that the dimensions of the four op-amps exceed the dimensions of the iBasso housing. So plastic ties would be useful
But all these inconveniences turned out to be such a trifle when I heard the sound quality of these op-amps from BursonAudio.
First of all, instead of the output power op-amps in the PB2 I put dummy boards with jumpers and tested different op-amps in the preamplifier stage with GAIN = 3.
Op-amps from Sparkos produce a very precise, layered sound. All instruments are very accurately positioned in space and there is a lot of air between them. However, the sound lack strength because the output current is about 50 mA.
Op-amps from MUSES have an output current up to 250 mA and they sounds very powerful, at the same time much more natural than Sparkos. However, there is no such airiness and lamination like in the Sparkos op-amps. The MUSES03 op-amps easy open up any headphones, even isodynamic like AlphaDog and high impedance dynamic like DT-1770.
And then I PUT_IN the V5-OPA-S - and they became a sunshine for my ears! They combined the best advantages of both op-amps tested above - the intensity sound of the MUSES03 and layering and accuracy of the Sparkos sound. However, the power output was not enough to open up tight headphones. I did not find the maximum output current specs for the V5-OPA-S in the manual, but comparing with the sound of MUSES03 it was obvious that the output current is much less than 250mA.
Therefore, for maximum power, I put the MUSES03 on the output power stage of PB2. And now I have an excellent desktop-portable setup on which I can test any headphones and DACs.
Although, sometime I want to try more neutral powerful op-amps in the output stage, may be it can be the OPA1622 type, because they does not color the sound at all, unlike MUSES03.
I want to express my great gratitude to Mr. Carlos for the provided samples of magnificent op-amps from BursonAudio.
The signal source I used was the balanced line output of the FiiO X7 player or iBasso DB2 balanced DAC output with Hidizs AP60-II player as USB transport.
When I got the op-amps from Burson Audio it were not V5i, but four V5-OPA-S pieces, which are higher grade than V5i. Packed very well, even plastic ties included to fix the op-amps in a horizontal position or upside down.
I have tested the different op-amps from the iBasso kit, but they do not impress me by the sound at all. So I bought the top op-amps from Sparkos and MUSES.
The supply voltage of the op-amps in the PB2 amplifier is +/-8V, but sparkos and muses can operates up to +/-18V. Therefore, I made the PB2 mod for powering it from external power supply with two 4S li-po batteries with total voltage near 30V. The high voltage supply for op-amps allow them to work in an optimal mode with minimal harmonic distortions and with higher slewrate.
In the V5-OPA-S specs, the maximum supply voltage is +/-15V, but they works OK on +/-16V supply voltage with minimal heating.
Of course, the size of the V5-OPA-S is not small at all, I think even the owners of some desktop setup will have problems with this op-amp installation. In my iBasso especially, the pads for op-amps are located on the board very close to each other and it was impossible to install it vertically in the board. So I had to make the extension board adapters.
The V5-OPA-S width is also so large that the dimensions of the four op-amps exceed the dimensions of the iBasso housing. So plastic ties would be useful
But all these inconveniences turned out to be such a trifle when I heard the sound quality of these op-amps from BursonAudio.
First of all, instead of the output power op-amps in the PB2 I put dummy boards with jumpers and tested different op-amps in the preamplifier stage with GAIN = 3.
Op-amps from Sparkos produce a very precise, layered sound. All instruments are very accurately positioned in space and there is a lot of air between them. However, the sound lack strength because the output current is about 50 mA.
Op-amps from MUSES have an output current up to 250 mA and they sounds very powerful, at the same time much more natural than Sparkos. However, there is no such airiness and lamination like in the Sparkos op-amps. The MUSES03 op-amps easy open up any headphones, even isodynamic like AlphaDog and high impedance dynamic like DT-1770.
And then I PUT_IN
the V5-OPA-S - and they became a sunshine for my ears! They combined the best advantages of both op-amps tested above - the intensity sound of the MUSES03 and layering and accuracy of the Sparkos sound. However, the power output was not enough to open up tight headphones. I did not find the maximum output current specs for the V5-OPA-S in the manual, but comparing with the sound of MUSES03 it was obvious that the output current is much less than 250mA.Therefore, for maximum power, I put the MUSES03 on the output power stage of PB2. And now I have an excellent desktop-portable setup on which I can test any headphones and DACs.
Although, sometime I want to try more neutral powerful op-amps in the output stage, may be it can be the OPA1622 type, because they does not color the sound at all, unlike MUSES03.
I want to express my great gratitude to Mr. Carlos for the provided samples of magnificent op-amps from BursonAudio.
