Is anyone building the DIY Pass F-5

Woody1911a1 · « **Reply #80 on:** 19 Mar 2011, 11:48 am »

it looks as though you have the wires between the v- diode bridge reversed . the input to the ps board v- should be connected to the - side of the diode bridge and the + terminal of the diode bridge connected to the ground of the ps board .

cheers Woody

Russellc · « **Reply #81 on:** 19 Mar 2011, 04:48 pm »

Quote from: Woody1911a1 on 19 Mar 2011, 11:48 am

it looks as though you have the wires between the v- diode bridge reversed . the input to the ps board v- should be connected to the - side of the diode bridge and the + terminal of the diode bridge connected to the ground of the ps board .

cheers Woody

Good eye! I cant tell from the pic if that bridge has the traditional "flat corner" so couldnt tell. That would cause some trouble likely.

Russellc

Russellc · « **Reply #82 on:** 19 Mar 2011, 04:53 pm »

Out of curiosity, what is the deal with the two fuses. Pass schematic only shows one. Not that its any big deal, its a difference and sometimes that is where a mistake can be made. (I seriously doubt this is it, but may bear thinking through the wiring.) It also looks like you used a DPDT switch rather than a SPST to impliment them. I'm trying to sketch this out.

Also, I had originally proposed to use those same terminal pieces you have for the thermistor and another member suggested they werent capable of high currents/voltages, but I dont know this and it cetainly would NOT be your problem. I'd like to know how they work out.

Recheck by comparing the FirstWatt power supply schematic with yours where the CL-60 thermistors attach.

You wiring isnt that much different, but when things ar changed, mis wires can be made. Keep on pluggin, you are almost there!

Russellc

strider · « **Reply #83 on:** 19 Mar 2011, 05:56 pm »

Cheers to you too Woody!

Didn't mess with it last night; today the wife took the kids for the day so I started back at it this morning. Saw the discrepancy in how the v- diode bridge was wired vs a picture in the build guide cviller was kind enough to put together for the boards he sold in a group buy. Just got done rewiring and voila, no popping fuses. Checked back here and you guys corroborated.

Thanks so much for helping work through the problem, beers are on me!

Quote from: Woody1911a1 on 19 Mar 2011, 11:48 am

it looks as though you have the wires between the v- diode bridge reversed . the input to the ps board v- should be connected to the - side of the diode bridge and the + terminal of the diode bridge connected to the ground of the ps board .

cheers Woody

strider · « **Reply #84 on:** 19 Mar 2011, 06:03 pm »

Russell,

Thanks for the help, it really made me go back, double check, and re-look at how I'd hooked everything up.

The 2 fuses are something I've done on all (read: 2) my other builds. Musta read somewhere that it add another margin of safety to the equipment. On this build it just doubled the amount of fuses I blew

The switch is a DPST fed by the 2 fuse holders. Those terminal blocks I've used successfully on a DAC I built last year, no issues so far.

Russellc · « **Reply #85 on:** 19 Mar 2011, 06:23 pm »

Great! I assume you are proceeding to fireup? Be careful, those fets are getting more and more rare!
Bear in mind this sucker pulls current unlike any DAC ever dreamed! You are going to love this amp!

Russellc

strider · « **Reply #86 on:** 20 Mar 2011, 12:11 am »

Now that I've gotten the fuses figured out, I turned it on and started measuring. 24.7v +/- at the respective V in on each board. -.41v at the output of the left channel and 0v at the right channel with the trimmer pots turned all the way down. The led for the left channel is lit but the right isn't. 1.74v at the input of the left side led, 24.0v at r/s.

I'm confused.

Woody1911a1 · « **Reply #87 on:** 20 Mar 2011, 12:47 am »

hey strider

guessing you have the polarity of the right led backwards . btw i'm just a newbie at electronics , but learning . i followed russel over here from another board

note the led connections on the cvillar boards have a square and a round contact . the led's before you installed them had one lead longer than the other . just switch the leads to the led .

if nothings smoking just go ahead and bias up

cheers Woody

Russellc · « **Reply #88 on:** 20 Mar 2011, 01:06 am »

Quote from: strider on 20 Mar 2011, 12:11 am

Now that I've gotten the fuses figured out, I turned it on and started measuring. 24.7v +/- at the respective V in on each board. -.41v at the output of the left channel and 0v at the right channel with the trimmer pots turned all the way down. The led for the left channel is lit but the right isn't. 1.74v at the input of the left side led, 24.0v at r/s.

I'm confused.

OK, you say "24.7v +/- at the respective v in on each board." I assume you mean the correct voltage is coming into the power supply board, or the amp board?

Russellc

Woody1911a1 · « **Reply #89 on:** 20 Mar 2011, 01:16 am »

hey russell , finally got the aluminum for my casework and have been cutting drilling and tapping all day . i'm still very confident these heatsinkusa 10 x 7" sinks are gonna work great .

i was listening to it all week uncased and it never got over 40c .

i'll have pics and specs tomorrow sometime

i'm still on moderation as a newbie here so anything i post takes hours to show up .

cheers Woody

Woody1911a1 · « **Reply #90 on:** 20 Mar 2011, 02:16 am »

also another thought on the -.41v on one channel means unless you have something else screwy , that your pots aren't really zeroed . if they were you wouldn't be getting that reading which is probably + .41 if you reverse the tester leads . you can check the pots by reading ohms across R3 for one and R4 for the other .

strider · « **Reply #91 on:** 20 Mar 2011, 02:21 am »

Sorry, that wasn't real clear. The voltage is correct coming into each amp board, but from there....

The more I look at it, I think I may have a couple different issues. There's definitely something different between the two amp boards considering the LED issue and the difference in voltage at the outputs, but I think there may also be something incorrect in both the amp boards as well. Had the amp on for over an hour, no signal, and the heatsinks didin't get the slightest bit warm. From my understanding of Class A, shouldn't the amp be the hottest when there's no signal?

I need to step back and look at the schematics of my boards and compare them to the FirstWatt F5. The amp boards I have are the V 2.0 boards from cviller which have additional positions for more output devices and cascoding. There seems to be a little confusion about which positions need to be populated for the stock F5 version. I posted a comment in his blog and am awaiting a reply.

I appreciate your help and interest in my project,

Ben

Woody1911a1 · « **Reply #92 on:** 20 Mar 2011, 02:40 am »

omg the plot thickens

never noticed you had THOSE boards . if i were you i'd buy the extra mosfets and other do-dads and go for it .

this newby moderation sucks .

strider · « **Reply #93 on:** 20 Mar 2011, 03:12 am »

This is the schematic for my board. There's some concern about which of the positions, Q101 or Q1, gets populated with the N type JFET.

Russellc · « **Reply #94 on:** 20 Mar 2011, 04:26 am »

OK, as I recall the board is labeled very clearly where the fets go on as to which hole is source, gate, etc. Get the data sheet by google for your device and see which leg is which. Initially there was some confusion, especially since one builder used zetex parts and another use another manufacturer. By looking at the data sheet and the markings on the board, it should be clear. even if the boards arent marked S, G, etc on each of the three holes, it can still be figured out by looking what trace hooks up to which part and then comparing it on the schematic and data sheet.

Russellc

Russellc · « **Reply #95 on:** 20 Mar 2011, 04:30 am »

Quote from: strider on 20 Mar 2011, 02:21 am

Sorry, that wasn't real clear. The voltage is correct coming into each amp board, but from there....

The more I look at it, I think I may have a couple different issues. There's definitely something different between the two amp boards considering the LED issue and the difference in voltage at the outputs, but I think there may also be something incorrect in both the amp boards as well. Had the amp on for over an hour, no signal, and the heatsinks didin't get the slightest bit warm. From my understanding of Class A, shouldn't the amp be the hottest when there's no signal?

I need to step back and look at the schematics of my boards and compare them to the FirstWatt F5. The amp boards I have are the V 2.0 boards from cviller which have additional positions for more output devices and cascoding. There seems to be a little confusion about which positions need to be populated for the stock F5 version. I posted a comment in his blog and am awaiting a reply.

I appreciate your help and interest in my project,

Ben

You might inquire over on the Pass forum on DIYAudio. Several have built with that particular board. I have only used the Daniels boards myself.

Russellc

Russellc · « **Reply #96 on:** 20 Mar 2011, 04:42 pm »

I saw you got clarification from Cviller on his blog. Thanks for that, now at least those who read the blog will see that little detail!

Was that the problem?

Russellc

strider · « **Reply #97 on:** 20 Mar 2011, 05:24 pm »

I had Q1 populated on my board. Haven't had a chance yet to double check anything today, still have to get to the parts store and buy more fuses. Last night I started second guessing what I'd figured out in regards to the direction to turn the trimmer pots and ended up blowing more fuses.

sts9fan · « **Reply #98 on:** 20 Mar 2011, 06:44 pm »

Well, I just finished wiring my PS. I am doing it point to point. Anyway it blew the fuse pretty quick with no load. I made it to about 40vac with a variac. Now the fun part.

strider · « **Reply #99 on:** 20 Mar 2011, 08:50 pm »

It is with heavy heart that I write this. At approximately 4:18 today, the .47ohm 3 watt resistors of the left channel glowed brightly, hung on for what seemed an eternity, but finally succombed and released the Magic Smoke. R113 (which I believe corresponds to R13 on the original schematic) followed suit, leaving a burn mark on the PCB. No idea what caused the problem, but it looks pretty bad.

Since I have a pair of the Peter Daniels' boards also, I think I'll order the resistors and thermistors and re-use everything else. Anything I should be concerned about in regards to the parts to be re-used?