GoodSoundClub - Romy the Cat's Audio Site

In the Forum: Audio For Dummies ™
In the Thread: LF Amplifier in biamping.

Post Subject: Sakuma’s syndrome?Posted by Romy the Cat on: 6/8/2012

This Sakuma’s is kind of BS. What I mean is that it has the appeal to be “good thinking” but only in the realm of marketing hype, something that the editor of “Direct Heating” had created around Sakuma. The reality is that the Sakuma’s TWO channel Amplifier is not truly interesting multi-amp solution, in fact it is VERY bad solution. For sure the Sakuma’s TWO channel Amplifier is a wonderfully vehicle for the “Direct Heating” to sell the Tamura iron, that is why the Sakuma’s syndrome was even created.

To understand the bogusness of the Sakuma’s TWO channel Amplifier you need to understand Sakuma’s personal objectives. He drivers a single speaker - stock Altec 7 – that is all that he cares. Sakuma never intend to use any DSET concepts, in fact he did not even understand them or have a need for them. He did clearly expressed it in his TWO channel Amplifier design.

Take a look, he has many bandwidth limiting elements sitting in chain. By doing it he sharpens the roll offs. The amp itself has no line-level filtration - the transformer after the second stage juts splits signal and then he uses the Altec’s speaker-level filters to shape the channel response. Very freaking intelligent! The performance of the former stages impact the performance/bandwidth of the LF amplifier – this is the horrible valuation of DSET concept and the bandwidth-specific optimization become impossible. Take a look at the transformer A4714 juts after EL34 tube. It has to be wide-band transformer as if it will be HF optimized than it will have inductance to give good LF for LF amp. If you however make this A4714 transformer with a lot of inductance, large with low section then you get a lot of capacitance hat will compromise you HF channel. The transformer TN6 and SYU-001 have to be bandwidth optimized but they are not. The whole amp is just a driver with transformer splitter with two separate power amps and speaker-level filtration – this is as stupid as it could be of one promotes the amp as “TWO channel Amplifier”. The idiocy of the design is even in the fact that Sakuma use two attenuators – one for HF and one for LF. This is foolishness as you need ONLY ONE attenuator.

I can go much longer but frankly whatever Sakuma’s does has very little interest in my view.

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