Is it a slow blow fuse?
A lot depends on how much capacitance/transformer you have in the supply. My v2 single mono with 625va transformer and 200,000uf of caps will blow a 4A slow blow fuse occasionally on startup.
A lot depends on how much capacitance/transformer you have in the supply. My v2 single mono with 625va transformer and 200,000uf of caps will blow a 4A slow blow fuse occasionally on startup.
You didn’t have a problem with amp gain...
You had a problem with preamp attenuation!
Glad you got it worked out. 🙂
Yes, they are slow blow. I have an 800VA trafo and 160,000uf of filter cap. I’ve got the soft start boards on the way in the mail. We will se how they do.
That’s exactly right. Im not sure how i did that. I had the 47.5K in my mouser order. But happened to grab the 47R5s when building. Anywho, the amps sound fantastic, I've had it burning in for a few hours now. I would like to thank the godfather of diy audio, Mr. Pass. Such a gift for the path of life long learning and to the world of two channel audio.
If I use a 17" long heatsink standing straight instead of front to back like normal, will it cool the top most transistor as we as the bottom most one?
no it would not. And when you dobbel the lenght of the sinks you only gain about 25% cooling capacity. So it's better to build deep then high.
Also, it's important that the sinks stands upright 90 degrees to get the most airflow up between the fins.
Also, it's important that the sinks stands upright 90 degrees to get the most airflow up between the fins.
Thanks AudioSan. I'll have to think on that. I'm really like the design with those sinks are standing straight up. I wonder how much less cooling there will be set that way.
As a tube guy I've swapped out different tubes and in most instances the sound was quite different depending on the tube. Is there such a thing with the F5T?
As a tube guy I've swapped out different tubes and in most instances the sound was quite different depending on the tube. Is there such a thing with the F5T?
Coming from the tube world you will find the f5 very interesting...
You could either love it or hate it, it’s all highly subjective. But Adjusting P3 will help you dial it in to a place you like.
You could either love it or hate it, it’s all highly subjective. But Adjusting P3 will help you dial it in to a place you like.
I had an F5T in my system for a month and really liked the sound. That's why I'm here��
My audio rack has 228mm of vertical space - can I get a 5U case in this space with feet on it? I'm considering an F5T v2 but I don't want to have to get a new rack.
My 5U is 217mm from shelf to top with the stock feet.
You better not have a shelf right above it though...cooling will suffer.
You better not have a shelf right above it though...cooling will suffer.
This is what I'm dealing with.
I wouldn’t do it. You are not going to gain much cooling capacity and the temps inside the chassis will be hot.
Even the 4U you have now will be cooler outside that rack. Airflow has a dramatic effect on the cooling capabilities of these chassis.
Other option would be some sort of fan setup for a 5U in that rack.
Another option is on the floor in the center, there is 420mm of vertical space. Currently occupied by a Cary Rocket 88.
My 4U chassis dropped 5deg C just by putting the factory, essentially letting air through the bottom vents. These things are more sensitive to airflow than I expected. You might be able to put it on the floor, but i would place a hard surface between the amp and carpet. Like a 1/2” granite slab or a hard wood. Then monitor the heat for the first few days. If need be, decrease the bias just a tad.
I agree with others that you would be better of with 4u if the space is that tight. Natural convection plays a big part in getting maximum cooling from the side mounted heatsinks. Increasing the space between the bottom of the heatsink and the shelf is a good way to encourage airflow. I built 2 amp stands for my F5V3 monoblocks so they have no shelves above them. I also use tall feet to help convection.
This is what I'm dealing with.
You have nice shelves, but at the bottom they are hard to see. I would build a baby sitter out of nice wood like the one I built with a usb fan.
That should be enough to keep the temperature down and the fan is quiet. You can buy them with a Pot as well.
Rush
Attachments
@McQuaide - If those are VTI racks (If they are, I have the same ones in a different color scheme) - you'd need to lift the rack just a wee bit for a 5U with the "isolation feet" to tuck it under the bar, but there's clearance. I have run the 5Us in the bottom slots and in "open air" on top. I get about a 4C difference from "open air" to the bottom. With the bias set normally on a F4, F5, Aleph J, SissySIT, and M2x - I've never approached 55C on the sinks - internal temps seem fine. I set the F5 to just a shade over 1A8 last week, and it's been in the rack for quite a while. My room stays around 70F year round. Whether it's a good idea or not... I leave my amps on pretty much all the time unless I'm out of town.
So... you might be just fine in PA. If you want it the coolest... then use a babysitter or put it on the top rack as others have said. Just thought I'd chime in since I think we have the same racks. YMMV based on the amps and the bias. F5T may run quite a bit warmer.
So... you might be just fine in PA. If you want it the coolest... then use a babysitter or put it on the top rack as others have said. Just thought I'd chime in since I think we have the same racks. YMMV based on the amps and the bias. F5T may run quite a bit warmer.