My 8" sections of HeatsinkUSA are nice and adequate for the job as proven by several others here. Then get some 1/8 inch 6061 aluminum for the top and bottom, some a little thicker for the face plate, and get to drillin' and Tappin'....
Dont worry, its easy, just take time with the tap.
Once your PS is measuring right, you're almost there. Double check amp boards, fet orientation, and begin power up.
Russellc
Just a quick update... I've got my new F5 board & F5 kit from diytech...
I've got it all installed and mounted.
I've set each pot to it's minimum, and while biasing, I've alternatively turned each pot up clockwise until I've maxed out at about .513 v (on R11 & R12) when the pots started to click.
I'm going to leave it for about an hour (to find out where it settles down to).
Any suggestions?
I've got it all installed and mounted.
I've set each pot to it's minimum, and while biasing, I've alternatively turned each pot up clockwise until I've maxed out at about .513 v (on R11 & R12) when the pots started to click.
I'm going to leave it for about an hour (to find out where it settles down to).
Any suggestions?
question for those more knowledgeable here :
could this be a result of the tech-diy kits now coming with low ids ,gr grade, fets ?
seems problems arose when he was supplying gr grade j74's and bl grade k170's where you can't get the bias high enough w/o the offset going off the scale (me included, problem solved when i bought 400 bl grade of each
) , but now he's including both gr k170's and j74's .
cheers , Woody
could this be a result of the tech-diy kits now coming with low ids ,gr grade, fets ?
seems problems arose when he was supplying gr grade j74's and bl grade k170's where you can't get the bias high enough w/o the offset going off the scale (me included, problem solved when i bought 400 bl grade of each
) , but now he's including both gr k170's and j74's . cheers , Woody
the problem both you and i had wasn't getting bias high enough , at least for me , i could get the bias as high as i wanted but along with it went the offset .
sounds like merlin's got the pots maxed out . i had plenty of adjustment , not sure about you .
hey Jim not trying to start an argument just thinking out loud . btw where ya been ?
cheers Woody
sounds like merlin's got the pots maxed out . i had plenty of adjustment , not sure about you .
hey Jim not trying to start an argument
just thinking out loud . btw where ya been ? cheers Woody
hey Jim not trying to start an argument
Sorry if it came off that way... I was just asking if I was actually missing something in the conversation or not.
Anyway, I haven't been posting much as I haven't been doing much audio project. I have a few, but no time to complete anything.
Christian thanx much for chiming in Jim , you don't have to tell me about that . because of a lil hurricane it took 12 extra days of hecticness to get the daughter off to college .
and Merlin , pm me your address and i'll mail out to you tomorrow a matched set of proper bl grade jfets
cheers Woody
Jim , you don't have to tell me about that . because of a lil hurricane it took 12 extra days of hecticness to get the daughter off to college . and Merlin , pm me your address and i'll mail out to you tomorrow a matched set of proper bl grade jfets
cheers Woody
Fantastic work.
Just a few simply questions. What is the voltage coming off the transformer? And whats the DC voltage leaving the rectifier (to the boards themselves?) I was thinking of messing around with one. Get a board, stuff it with components (not expensive audio grade, but regular caps and resistors) Installing the outputs, and mounting it to an old but large heatsink. Then use a cheap transformer (not toroid), and a regular bridge rectifier, and make a one channel F5.
Just a few simply questions. What is the voltage coming off the transformer? And whats the DC voltage leaving the rectifier (to the boards themselves?) I was thinking of messing around with one. Get a board, stuff it with components (not expensive audio grade, but regular caps and resistors) Installing the outputs, and mounting it to an old but large heatsink. Then use a cheap transformer (not toroid), and a regular bridge rectifier, and make a one channel F5.
You could blow a fan on said heatsink and have two channels...
Anyway, the 18v secondaries are around 18v under load, and rectified about 24v.
You will still need the dual secondaries transformer for one channel, as the supply 24-0-24.
Regardless how you proceed, the amp is a great project, and you will enjoy the journey, and especially the results!
Anyway, the 18v secondaries are around 18v under load, and rectified about 24v.
You will still need the dual secondaries transformer for one channel, as the supply 24-0-24.
Regardless how you proceed, the amp is a great project, and you will enjoy the journey, and especially the results!
18-0-18, as it will rectify up to 24v.
I think a 300VA Antek will work, but I know (for 8 bucks more) a 400 will do the job. Single supply for stereo. So look for a 4218 from antekinc.com
There may be cheaper, but antek havs good quality, the few I have bought from them have been very nice.
I think a 300VA Antek will work, but I know (for 8 bucks more) a 400 will do the job. Single supply for stereo. So look for a 4218 from antekinc.com
There may be cheaper, but antek havs good quality, the few I have bought from them have been very nice.
Just to make sure I know, the 18-0-18 transformer has to be rated for at least an X amount of amps, or it will go up in smoke correct?
So this is the one I should get?
https://www.antekinc.com/details.php?p=698
And this one might work:
https://www.antekinc.com/details.php?p=685?
I will play it safe, and get the AS-4218. Now will this transformer be able to run two amp modules?
Amp modules means the circuit board with the MOSFET outputs that are from Peter.
The 300VA would work, but most around here seem to use larger ones, like the 400VA. There is also a 600VA model from that same source that some have used. My 1st F-5 was built dual mono and I used two of the 300VA models. I have seen others use two 400VA from Antek. My current build is using a single 500VA. All of these being 18v x 2.
RussellC