2 pairs version was tested with 5-6 different type 4ohms speakers, and it works without any problem, even with close to the maximum output level.
I have downscaled version, uses 2SC3519A/2SA1386A, and runs with +/-40V for 60W/8ohms.
Sajti
Sorry I was not accurate enough:
The bigger version use +/-55VDC (2x40VAC power transformer), and gives about 250W/4ohms. 2 pairs of 6145/2223.
The downscaled version use +/-40VDC (2x28VAC power transformer) and gives 60W/8ohms. 2 pairs of 3519/1386.
The original version was planned to use 3 pairs, but I felt it too much.
Sajti
I used 3pairs of 230W devices on a dual 40Vac transformer and it gave 311W into 4r0. But it is not man enough to be rated for 4ohms reactive speaker use. So it is rated for 6ohms or greater. It gives 170W into 8r0 and will play all day and for party duty. I think it might even double up as PA duty, but only for 8ohms, or greater. My Tannoy Leopards are close to 10ohms.
2pair of 160W devices into 4ohms is sailing very close to the sirocco.
2pair of 160W devices into 4ohms is sailing very close to the sirocco.
Hmmmm.. I never feel like that. Anyway You can try 6145/2223, maybe You will feel them better.
Sajti
Hi,
this will be my first version with 3519/1386, but I did this amplifier with 21193/94, and with NJW0281/0302. Currently the 6145/2223 is the best sounding version to me.
Sajti
NIce.
Brilliant idea to use the board mounting screws for the transistors also.
Simple and effective like it should be.
Hi Guys
It is surprising that anyone would use carbon resistors to build an audio amp these days!
Back in the early days of Bryston's manufacturing, the power amps were at the limit of the test equipment resolution of the day (and still are today with respect to modern test systems). They found that changing the feedback resistor from coarbon to metal-film cut THD by more than half. It is well-known today but not back then that carbon resistor THD has a voltage-dependent portion, so having a large audio signal across one generates a lot of distortion within the resistor.
Sajti, you said your test equipment cannot resolve below 500ppm, but that does not mean you have to settle for "carbon performance" - hehe. Eliminating distortions where we can is always a good thing and you might make a subsequent change that would be noticeable were the carbon distortions already removed.
The build looks beautiful!
It is surprising that anyone would use carbon resistors to build an audio amp these days!
Back in the early days of Bryston's manufacturing, the power amps were at the limit of the test equipment resolution of the day (and still are today with respect to modern test systems). They found that changing the feedback resistor from coarbon to metal-film cut THD by more than half. It is well-known today but not back then that carbon resistor THD has a voltage-dependent portion, so having a large audio signal across one generates a lot of distortion within the resistor.
Sajti, you said your test equipment cannot resolve below 500ppm, but that does not mean you have to settle for "carbon performance" - hehe. Eliminating distortions where we can is always a good thing and you might make a subsequent change that would be noticeable were the carbon distortions already removed.
The build looks beautiful!
Hi,
it was a surprise, that there are some companies, which are still using carbon film resistors, even in their higher quality equiments too.
I used Takman REX resistors, which has qutie good reputation within the diyers. If You check the schematic of the V4, You will find, that there are many resistors, which are running with low, and almost constant current. The only critical part is the feedback network, where 22mA AC current runs over the resistors. But the dissipation of them is about 15-20% of their limit.
The basic version of V4 use DALE RN resistors, and it has much more relaxed sound comparing to the carbon film version. The Takman version has very vivid, exciting and thrillig sound, but it You will be tired with long term listening.
Generally I use the DALE version, and my next plan to build one more amplifier with Takman REY resistors.
Sajti
it was a surprise, that there are some companies, which are still using carbon film resistors, even in their higher quality equiments too.
I used Takman REX resistors, which has qutie good reputation within the diyers. If You check the schematic of the V4, You will find, that there are many resistors, which are running with low, and almost constant current. The only critical part is the feedback network, where 22mA AC current runs over the resistors. But the dissipation of them is about 15-20% of their limit.
The basic version of V4 use DALE RN resistors, and it has much more relaxed sound comparing to the carbon film version. The Takman version has very vivid, exciting and thrillig sound, but it You will be tired with long term listening.
Generally I use the DALE version, and my next plan to build one more amplifier with Takman REY resistors.
Sajti
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