Nelson Pass DIY F5 build

[dokblues]

Very nice little project you have there Jeff! I am looking forward to the updates! Great looking chassis BTW.

 

[specialidiot]

This evening I spent another couple of hours getting the chassis squared away. I mounted the feet, torriod, power supply pcb standoffs, rectifiers, RCA inputs, binding posts, and the AC entry module.

I also studied the power supply schematic and I believe I have a handle on it.

Tomorrow is church night so I probably won't get anything done.

While I worked this evening I listened to ejfud's F5 with my Foreplay III for a preamp and driving my Cornwalls. I could live with a system like that!

 

[specialidiot]

Non-update update:

I went down to stuff and solder the power supply board and couldn't find the resistors so I spent the rest of the evening going over the BOM and what I have on hand.

New ones on the way from Mouser, so I'll probably find them tonight.

I'll get the driver boards done and wire up the AC this weekend, the resistors should be here on Monday.

duh.....

 

[specialidiot]

I worked on the driver boards last night and made a mistake by putting one of the transistors in backwards. Of course I butchered the one of the pads pulling it out, so now it looks like ass. For the time being I am going to hardwire that leg but its going to drive me nuts to know its there, so a new board is on order.

 

[doucanoe]

You have a pic of the above "oops" Jeff? I'm just reading along and trying to understand how one of these go together. Pictures help maroons like me. :yes:

RC

 

[gmilitano]

That is looking great.

 

[specialidiot]

You have a pic of the above "oops" Jeff? I'm just reading along and trying to understand how one of these go together. Pictures help maroons like me. :yes:

I'll post an update with pics later tonight. I'm "goin' in" to finish up my kitchen tiling DIY right now... can't be deterred....

 

[240sx4u]

Man, that is a good looking build..... nice work man. I wouldn't mind seeing photos of that kitchen tile deal too LOL. I have wanted to do some tile work at my house.

 

[M Jarve]

Looks like it'll be something else. Maybe done by the next time I get to the Cities?

 

[specialidiot]

Man, that is a good looking build..... nice work man. I wouldn't mind seeing photos of that kitchen tile deal too LOL. I have wanted to do some tile work at my house.

New thread started at http://audiokarma.org/forums/showthread.php?p=2702143#post2702143

Looks like it'll be something else. Maybe done by the next time I get to the Cities?

Hope so, as long as I haven't damaged the PCB beyond my super-rusty troubleshooting skills I'll be OK. If I run into issues, I'll likely need a scope to follow the signal paths.

OK, heading downstairs, I'm Goin' In.

 

[doucanoe]

OK, heading downstairs, I'm Goin' In.

Good luck.





RC

 

[specialidiot]

Good luck.

rofl.....

Well I think I'll be OK.

Here are the two driver boards with a pen for scale. Tiny, eh?

The damaged pad is the lower board, right in front of the trim pot on the right. The tranny that came out of that blasted hole is laying in front of the other one.

Here's the repair. Not quite pro quality but it checks out against the other board.

Now I suppose you are asking yourself: what's he gonna do when R11 comes in? I'm kinda wondering about that myself.

In other news, I powered up the torroid and rectifier circuit, both sides check out OK.

 

[edd9000]

Where can i get the boards? looks a fascinating amplifier.

edd

 

[specialidiot]

Where can i get the boards? looks a fascinating amplifier.

edd

everything is here: http://www.diyaudio.com/forums/showthread.php?s=&threadid=134554

It's just impossible to find. Basically get an account at diyaudio.com and get together with cviller. The three boards (2 drivers, 1 power supply) were $40 shipped from Denmark, which took a couple of weeks.

 

[edd9000]

Thanks, I had not spotted the gb for pcbs when i looked on there

edd

 

[specialidiot]

Well here we go!

I was away for the weekend "up north", not at the fest. Last night I finished up soldering in the driver FETs and getting everything mounted and wired up. Lots of measure twice, cut once and soldering.

Here's what the guts look like.

The instructions call for warming it up for a couple of hours prior to setting the bias and offset, so I let it run overnight and all day. Just at idle, those heatsinks get pretty warm.

Here I am getting close to correct voltages on the current measuring resistors along with tolerable DC offset. I had to run to Harbor Freight where I picked up the two meters for $2.99 each. I think I would have went nuts with only one meter here.

Finally everything looked ready to go. I brought out my Foreplay III and my ipod and a pair of Blose outdoor monitors that I use for tests. No noise, nice. First tunes up are what I always play on new gear: Little Feat's "Waiting for Columbus", of course!

It sounds like its supposed to, quick and clear. Not much critical listening with these test speakers though.

I'm still waiting on a blue jewel lamp for the front panel so I have that to drill out and wire, then dress things up pretty inside, button her up, and rack it.

Final pictures and impressions in a couple more days.

 

[doucanoe]

Looking great Jeff! Get that thing done so you can loan it to me already would ya

RC

 

[dokblues]

Looking good there Jeff! Can`t wait to see the finished project. :thmbsp:

 

[zenith2134]

:thmbsp: Nice work. That looks like it sounds excellent.

 

[RayW]

I was away for the weekend "up north", not at the fest.

You missed a good'n.

Just at idle, those heatsinks get pretty warm.

We had Gary's at the fest sitting next to a 45wpc hotrodded ST-70 tuber from Jaymanaa. That particular part of the room was pretty warm.

It sounds like its supposed to, quick and clear. Not much critical listening with these test speakers though.

Have the Indignias made it to you yet? That combo sounded really good at the fest.