250w 8ohm amplifier

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#401
Hi Guys

"Do not directly connect the ground plane to the CT"

That directive negates the purpose of the CT which is to BE the reference.

Really, through out the other bridge (i.e., put it back in the drawer) and wire ONE bridge correctly and place the CT correctly.

Terry, if you have my gerbers then you also have the proper drawing for a power supply. Part of DIY is making modifications to assemblies and improvising for a better result. Using two bridges here will distinctly give bad results.

Have fun
Kevin O'Connor
 
#402
Thanks Guys,

I should have just tried it before I bothered you. No matter how I hooked it up it didn't work. I pulled the bridges off the board and just used a 35A bridge in front of it. Works perfectly. I'm getting +-93V unloaded. This thing ought to be a real window shaker. 😀

Hi Kevin,

Since you are checking in, can I use MJE15032/33 for the drivers? They are still 250V parts. I used MJE340/350 for the VAS just because I had lots of them. Same reason I'd like to used the 15013/33, I already have a couple dozen of them. 🙂
 
#405
AJT,

If you go to Kevin's website and go to the HiFi design downloads page and then click on LTT4, the name of this amp, You can either pay the $4 for everything or there is a link to just DL the gerbers for free. I already had the Gerbers from a while back but I went ahead and paid the money so I could have the written documents. Kevin goes through the design piece by piece which was a really good learning tool for me.

Thanks for the info on the drivers. I was fairly confident they would work.


Blessings, Terry
 
#407
I will have some boards available once I get it tested and proven. It took me over a month to get these.
 

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#409
I'll have to check what they cost me. I'm not looking to make a profit. they wouldn't make just two. I had to buy in groups of 5, which of course doesn't work out for stereo so I bought 5 pair. I figured someone else would be interested in trying the amp too. Let me get it built first so I can make sure it works as is. I should have the rest of the parts first of next week so I should have it playing by the end of the week. Might as well get the bugs worked out first.

Blessings, Terry
 
#412
still4given said:
I'll have to check what they cost me. I'm not looking to make a profit. they wouldn't make just two. I had to buy in groups of 5, which of course doesn't work out for stereo so I bought 5 pair. I figured someone else would be interested in trying the amp too. Let me get it built first so I can make sure it works as is. I should have the rest of the parts first of next week so I should have it playing by the end of the week. Might as well get the bugs worked out first.

Blessings, Terry
Click to expand...

sounds reasonable....

Kevin sure makes good deal in his website, i am not aware of any other giving the same deal....:cheers:
 
#415
Hi Andrew,

It glowed fairly bright. I used a variac so it didn't get really bright, but enough to show it wouldn't work. I tried all combinations. As long as I had two connections shorted together it wouldn't work.

Hi Ranchu,

You and AJT are each ear-tagged for a pair. 🙂 Give me a week to test it. If the two of you could PM me with your address I will find out how much shipping will be. I may need one pair for backup, so that will mean I can help out three people or four if these go well.

Blessings, Terry
 
#418
I don't have 110/120 to experiment with.
But I guess that provided the bulb suits the supply voltage it does not matter.
What does matter is the Bulb Wattage. It determines at what current it starts to turn on.

I have a wide range that I can plug in: 25W to 150W.
60W will start up a 1kVA transformer, if small smoothing caps are fitted.
I have not yet added a second bulb holder, so that I can plug in two in parallel.

Probably soon, because I use this often, possibly 5 times a week.
 
#419
Yeah, you make a good point. I have always used this 150W just because I already had it laying around. I should get some lower wattage ones to have on hand. My light bulb tester is always plugged into my variac so everything usually gets brought up slowly while watching the light. It can't tell you how many times it has saved my butt.
 
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