Looking good, Stan. What is the DAC chip used?
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Looking good, Stan. What is the DAC chip used?
As mentioned in an earlier post, the Bushmster is based on all the good ideas and mods of the previous designs, plus some new ones:). There are no muting relays and their driver circuits. There is also no line output output stage. So no line output opamps and associated caps. It's a DC line output after all so no caps in the signal path to the output RCA sockets. There is also no variable output. The input selector circuit has also been simplified from a multi transistor, latching circuit, and selector diodes, to a microcontroller ;). And yes, I have used SMD where possible. They proved to be far less noisy in the TC-7510. The power supply is also far more compact due to the use of the latest generation LDO regulators. Those things are a mere fraction in size to the 78XX regulators that they replace.
The receiver and DAC chips are also far smaller in footprint. The board has also been laid out so that each section is as far away as possible from any other section. This helps to reduce the possibility of noise bleeding into adjacent circuitry.
I settled on the WM8524 after experimenting with a bunch of other ones. The manufacturer's specs looked less than spectacular, but the prototype DAC I built with it to try out the chip performed better than the Gatorized Caiman. And then I discovered that the SNR of the Rega DAC is the same as the Bushmaster :eyebrows:.Quote:
Originally Posted by MartinT
So +ve and -ve rails for output capacitor-less operation? Nice.
Nope. As I mentioned in an early post, some of the techniques I used in the design of the Bushmaster are likely to be of great interest to other designers;).Quote:
Originally Posted by MartinT
Intriguing!
That looks great. Do you have some specs for the headamp part of it too?
bit early...?
I'm sure Stan wont want to give away design info for a product not brought to market yet! ;)
Still, no harm asking!
I see the "wire mod" is a keeper! :lol::lol:
Maximum output swing is 8V peak to peak at the headphone socket. Output current is dependent on the opamp used, which also means that the bass level is dependent on the opamp used. I'll ship with the LM4562 in order to satisfy those who don't want too much bass. ( Yes there are loads of them...). But for proper bass drive, I use the THS4032 in my own setup with its 350mA capability. You should hear those K701 shift some air without any hint of distortion.Quote:
Originally Posted by jostber
As for musicality: well if you liked the Caiman headamp section then you are going to be smitten by the Bushmaster. But don't just take my word for it. Feel free to drop by with your expensive dedicated headamp and compare it to the Bushmaster.