Many questions on Zen V4

[FrankDIY]

Hello, I am in the process of buiding my first true audiophile amplifier and I have many questions for you and will appreciate any answers

Today I have cut my heat sink bar in 8 sections of 9'' and will assemble the chassis like the picture. I have used a 10'' Freud aluminum saw to do the job.

My goal is to build a no-compromise amplifier.

Following are my questions:

1. How can I polish the extremity of the heat sink section and which tool should I use to do the job (preferably by hand)?

2. What is the best diode bridge I can use for the power supply?

3. I plan to mount one transistor on each section of the heat sink, what kind of wire should I use to connect the transistor to the PCB? Gauge? Silver? Solid?

4. What kind of wire should I use for signal path (input and output) and where I can buy them?

5. Power supply: should I use the original design or should I build a PI filter?

6. Is is a good idea to use WBT silver solder to populate the PCB and make the wire connection?

I am sure there is more to come...

Thanks!

[Panelhead]

Each weekend I get a little more done on my own Zen V4. Here are my own misguided opinions on this.

For the diode bridges I used some 200v, 20A MUR discrete diodes to build some better quality bridges. Used the same for the bridge going to ground.
Look at the recommended power supply. The listed 50v caps before the regulator are very marginal. I used a 10,000 ufd 63v, 4 ufd choke (.23 ohm DCR), 10,000 ufd 63 v cap CLC filter. THis may be an improvement over the power supply listed.
The wiring is not critical for the power supply and using solid core of a guage heavy enough for the currents would stress the solder connections. Some 16 guage stranded wire should work great for high current wiring. The signal path wire is a personal thing, but I am using a XLO solid core sourced from Michael Percy. The 26 ga is great. I thought of using the Vampire CC magnet wire for this too, but I do not think it would have much effect.
Wiring up hard wire looks good, but I purchased the boards from PassDIY. This hould help with hum, but the low impedances seen in the circuit help even more.
Once yours is done let us know. If my wife, kids, and job would give me a whole day to work on it mine would be playing. But getting a hour here and there it may be a few more weeks.
Tapping the holes in my heatsinks has been the most frustrating part. I have broken a few off now. I think Ineed to back them out more often to clean the threads. But live and learn.

George

[JoeBob]

For the wire I'd reccomend solid enameled magnet wire, a thicker gauge makes it easier to work with, since it's solid it'll hold it's shape and is easy to neetly place in the chasis. Apparently some say it "sounds" good too, but to me wire is wire. As for the bridge, go with a good 35A bridge, with big caps you don't want to blow up your diodes (the smell of burnt diodes sucks when they're discrete and you spent forever setting them up neetly in the circuit and raplacing them is tedious).

[moe29]

since it's your first amp, i'd purchase the boards and Q-pack
from pass DIY. Of course with that setup you mount all 3
MOSFETS to 1 heatsink... maybe to late since you already cut
your sinks?

not that i'm a pro at building amps, but anything to make the
process easier is always a plus in my book! Having the whole
Zen V4 article to help build the amp is huge too.

just my thoughts...


m.

[faustian bargin]

holy moly francois. that's gonna be one intimidating-looking amp.

for question #1, i imagine you could use an orbital sander, or a belt sander. only thing is, i don't know what kind of sandpaper you should use.

if the surface looks okay already, and all you need to do is remove burrs from the edges/corners, then you could probably just use a grinding tip on, like, a drill or a dremel maybe.

hope that gives you some ideas anyway.

wow, 8 heatsinks - are you doing 4 channels, or just 2? i thought there were only 2 transistors per channel that produced much heat...?

you don't have any leftover pieces you want to get rid of do you?

/andrew - can't wait to see this one put together

[FrankDIY]

Thanks for your answers.

Moe29, I have already bought the PCB from PassDIY because this is the only way to reward Nelson and to encourage him to continue to support the DIY community.

I think it is a better idea to separate each transistor to spread the heat dissipation among several heat sinks. I have look at the Zen V4 published on the passdiy site and they are nice but I think they all suffer from overheating. I think this is the best approach unless you spend big money (> 200$ US) on a custom heat sink.

[moe29]

Do all 3 of the heatsink mounted MOSFETS dissipate the same
amount of heat? For some reason i thought Q1 runs the hottest.
...maybe i'm totally off base.

i see!... i think i remember Mr. Pass saying in one post that you
could separate the MOSFETS from the board up to 6" or so...

but that's just off of memory. Maybe you could mount the board
and one MOSFET on one heatsink and then use wire to connect
the other 2 to sinks on the left and right...

it's late, i should crash, mostly i just wanted to say good luck
and keep us posted - with pics!

m.

[FrankDIY]

If I remember well, two of them are dissipating a lot of heat and the third one is not dissipating a lot. There a thread on this, but I am lazzy to search and give you the link. Since all the four section will be connected together with aluminum, I think it should also act as a big heat sink.

[UrSv]

Originally posted by moe29
Do all 3 of the heatsink mounted MOSFETS dissipate the same
amount of heat? For some reason i thought Q1 runs the hottest.
...maybe i'm totally off base.

i see!... i think i remember Mr. Pass saying in one post that you
could separate the MOSFETS from the board up to 6" or so...

but that's just off of memory. Maybe you could mount the board
and one MOSFET on one heatsink and then use wire to connect
the other 2 to sinks on the left and right...

it's late, i should crash, mostly i just wanted to say good luck
and keep us posted - with pics!

m.

Since current is about 2 A and the voltage drop in the regulator is a little less than 10 V and the voltage drop in the amp is about 20 V per transistor it works out as roughly 20 W for Q5 as the regulator transistor and 40 W each for Q1 and Q2 in the amp part. That makes up the 100 W total dissipation.

[FrankDIY]

Here is the thread: my heatsink calcs for Zen v4

Any others answers for my specific questions?