50w Single-Ended BAF2015 Schade Enabled

[ne5532]

I agree with you
I also want to make this amplifier.

 

[Ben Mah]

I did some research and radiation may not be very effective. However, the large mass will absorb more heat while raising the heatsink temperature less than with a lighter weight heat sink, and there will still be some convection current. It might not be the most efficient heatsink but I am thinking that the large size for the amount of applied heat will result in reasonable heatsink temperature.

 

[Ben Mah]

Some interesting reading on heatsinks:

http://www.thermalsoftware.com/vert_vs_horz_sink.pdf

Design your heat sink to operate with natural convection in two easy steps - Priatherm

 

[Soundhappy]

The fins are similar to the fins in Soundhappy's heatsinks (see post #593).
The heat sinks weigh 20 pounds each so I am hoping that they are adequate for 200Watts.

Soundhappy,

What are the dimensions and weight of your heat sinks?

Hello Ben Mah

Lenght | 33.5 cm = 13.18 inches
Width | 30.5 cm = 12 inches
Depth | 13 cm = 5.11 inches

Weight ~ 15 kg = 33 pounds each

IXYS bias circuit if 5K trimmers are ready waits in the drawers is a great Mr. Pass version

 

[Ben Mah]

Hi Soundhappy,

Thank you for the information.

The heatsinks that I purchased are about 2/3 the size of yours. Hopefully they will be adequate.

How hot do your heatsinks get (ambient and heat sink temperatures)?

I can always add fans if necessary.

 

[Soundhappy]

How hot do your heatsinks get (ambient and heat sink temperatures)?

I do heatsinks 5 seconds hand touch tests after 1 hour warm up and is hot but OK not too much.
Important is the empty space all around.
With thick front panel and big aluminium amp chassis box is a physical extension for heatsinks dissipation.

 

[Ben Mah]

Thanks for your input.

I will build the amps as monoblocks in aluminum enclosures, with lots of ventilation holes in the boxes. The boxes will only be about 300mm deep x 230mm high x 170mm wide, so not large, but they will absorb some of the heat. The amps will have lots of free space around them.

Since I have efficient speakers, I will not try to push the power envelope. I will get the Antek 45V transformers instead of the 50V.

I also have other SIT amps that I can use during the summer so I can use this amp in the winter only if heat becomes an issue. I have electric baseboard heating anyways so Class A amps are winners in the winter. I get music and heat for the electricity consumed.

 

[Soundhappy]

Smart logic Ben Mah

Warm Your heart with the music and house room with large size heat sinks.
Low impedance buffer are great friend for wide frequency response.

 

[dantwomey]

Can I turn the bias and B+ on at the same time or should the bias be present a few seconds before B+?

Regards,
Dan

 

[Soundhappy]

It's important to get bias voltage before B+ in case of use depletion transistors SIT's so current do stay in safe range.
With Mr. Pass bias circuit this is happen naturaly because small electrolitics charge quickly
and PSU electrolitics are much bigger and slow = time delay

 

[dantwomey]

To-264 are cost economic but they don't have look of Digital-Do-Main 2SK77B
Schade version SIT simulation with hockey puck IXFN have similar triode curves,
all parameters and yes that " style" package.
I like it very much Sir Rothacher pcb's solution show on the photos above.Thx to Audiohobby.com.
Traditionaly after BAF 2015 Sir Pass write for Diyers new passionate article so i stay in tune....

Best regards

How challenging is it to branch out into some basic DIY PCBs like Sir Rothacher did?

Regards,
Dan

 

[Soundhappy]

Any PCB design software installed on Your computer ?
Small dimensions boards are cheap.
Make separate : CCS , amplification stage , bias circuit with simple jfet buffer included.
PL amp with IXYS are example. Have a nice day

 

[enochRoot]

Interesting. Where did you get the photo? And I see he's only using 220uF instead of 1000uF in the schematic.

 

[Soundhappy]

This photo is XA.25 amplifier 6moons audioreviews: Pass Labs XA25
Similar PCB's style design are possible to make for Schade 50W

 

[enochRoot]

I think I'll be putting some screw access holes in my PCB Very slick!

 

[dantwomey]

Any PCB design software installed on Your computer ?
Small dimensions boards are cheap.
Make separate : CCS , amplification stage , bias circuit with simple jfet buffer included.
PL amp with IXYS are example. Have a nice day

Very interesting.

Regards,
Dan

 

[Soundhappy]

PCB making, PCB prototyping quickly and easy - STEP by STEP

With CNC machines we can make PCB's with less chemicals products.
Other solution: professional quality small size boards made in China cost few bucks

 

[dantwomey]

PCB making, PCB prototyping quickly and easy - STEP by STEP

With CNC machines we can make PCB's with less chemicals products.
Other solution: professional quality small size boards made in China cost few bucks

I think I’m going to start out with KiCAD.

KiCad EDA

Regards,
Dan

 

[vdi_nenna]

Dan,

Be sure to get a 10,000 ft view of how KiCAD works. There are several major steps to producing a PCB with KiCAD. It will take a lot of the mystery out of designing a PCB.
I'm still learning, but knowing the major steps helps.

 

[dantwomey]

Dan,

Be sure to get a 10,000 ft view of how KiCAD works. There are several major steps to producing a PCB with KiCAD. It will take a lot of the mystery out of designing a PCB.
I'm still learning, but knowing the major steps helps.

I picked KiCAD on a whim. All I did was google 'best free PCB software' and it came up on a list of ten. I'm hoping the learning curve isn't too steep because I just want to produce some very simple starter PCBs for fun.

Regards,
Dan