Finally everything connected and turned on
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Adjusting the offset and quiescent current is not complicated and does not take long. Quiescent current is not adjusted in the original scheme, but I added that option mostly because I want to do some experiments with the replacement of transistors. So far I use IF170A, ZTX851/951 and 2SK1058/2SJ162. The current through IF170A is 1.2mA, through ZTX851/951 it is a little higher than in the original, about 18mA and through the output laterals is 140mA. ZTX851/951 are the only ones that are thermally loaded but meet the SOA graph. The output offset is only a few millivolts and is stable. The heatsink has dimensions of 20x8x4cm and satisfies even when listening loudly, the power supply voltage is +/-27V. So far I have only made basic measurements, for the more thorough ones I have to get a new sound card but the rectangular signal looks great on the scope, there is no noise or hum at the output. It works perfectly .
I won't say much about the sound because it has only been working since last night, but I must admit that I am satisfied and maybe even surprised by the sound quality. Kudos to JM Plantefeve, who I hope follows this topic.
. Adjusting the offset and quiescent current is not complicated and does not take long. Quiescent current is not adjusted in the original scheme, but I added that option mostly because I want to do some experiments with the replacement of transistors. So far I use IF170A, ZTX851/951 and 2SK1058/2SJ162. The current through IF170A is 1.2mA, through ZTX851/951 it is a little higher than in the original, about 18mA and through the output laterals is 140mA. ZTX851/951 are the only ones that are thermally loaded but meet the SOA graph. The output offset is only a few millivolts and is stable. The heatsink has dimensions of 20x8x4cm and satisfies even when listening loudly, the power supply voltage is +/-27V. So far I have only made basic measurements, for the more thorough ones I have to get a new sound card but the rectangular signal looks great on the scope, there is no noise or hum at the output. It works perfectly
.I won't say much about the sound because it has only been working since last night, but I must admit that I am satisfied and maybe even surprised by the sound quality. Kudos to JM Plantefeve, who I hope follows this topic.
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Thank you,e_fortier
The amplifier plays beautifully, I am satisfied with the sound considering the complexity of the amplifier. But it can't compete with A class amp like Le Monstre or JLH69 but it has the advantage of low quiescent current.
The next step is the installation of the regulator. It will be the same as in my Le Monstre. I'm really interested in the effect on the sound, especially with this type of amplifier.
The amplifier plays beautifully, I am satisfied with the sound considering the complexity of the amplifier. But it can't compete with A class amp like Le Monstre or JLH69 but it has the advantage of low quiescent current.
The next step is the installation of the regulator. It will be the same as in my Le Monstre. I'm really interested in the effect on the sound, especially with this type of amplifier.
Yesterday I started playing with driver transistors, to begin with instead of ZTX851/951 I inserted TTA006B/TTC011B. As far as the sound is concerned, there are no significant differences, the ZTX may have a slightly more open sound, the TTA/TTC a little better in bass .
The games continue
.The games continue
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Finally, the regulators are close to being installed in the amplifier, I still have to thoroughly test and adjust them. The output voltage is +/-25V and the input voltage is +/-28V. It is Walt's Jung SR regulator, but modified for 10A (and more) current.
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Today I installed the regulators in the amplifier. And it sounds great, a total change of sound in all aspects. This is the third amp after JLH69 and Le Monstre that I have tried with these regulators and each time with the same result , with a smile on my face .
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Until yesterday I was listening to Le Monstre because it sounds much better than 'cube', but since yesterday afternoon I don't know what to think anymore. Maybe it's the initial euphoria, but now it sounds better to me than Le Monstre. I have listened to a lot of amplifiers in my life, as I was also involved in sales for a while, but I always preferred the sound of the A class (it's all Mr. Pass's fault ). But the 'cube' plays well enough as an A class.
The same regulator was used for all three amplifiers and each amp has its pluses and minuses, but these are minor differences. I am satisfied because I finally have a summer amplifier that does not require me to turn on the air conditioner.
). But the 'cube' plays well enough as an A class.The same regulator was used for all three amplifiers and each amp has its pluses and minuses, but these are minor differences. I am satisfied because I finally have a summer amplifier that does not require me to turn on the air conditioner.