My amp have never been over 20 celsius above ambient at heatsinks base.
12 celsius above ambient at idle after about 1 hour. But this amp have the sinks inside the chassis. and 5 channels. bias is set at 70mA pr outputpair. And +/- 57V rails.
I did HFE matching of the LTP transistors. Other then that i did not do any matching.
12 celsius above ambient at idle after about 1 hour. But this amp have the sinks inside the chassis. and 5 channels. bias is set at 70mA pr outputpair. And +/- 57V rails.
I did HFE matching of the LTP transistors. Other then that i did not do any matching.
No one has answered my question about the D-BC option diode on the board whether it is necessary or not. I am sure someone who has stuffed these boards knows the answer but it appears that there is very little interest in this amplifier anymore. Understandable considering how long it has been since it was designed. It doesn't really matter because
I am going to use one but it would be nice to have an answer.
I am going to use one but it would be nice to have an answer.
D-BC is the baker clamp option.
You should use this option to help protect your amplifier.
Baker clamp - Wikipedia
Search this thread for bakers clamp and you should find more info too.
Last edited:
The game is afoot! I've read hundreds of pages in this thread, and it has been very helpful. Now it's time to build. I have the universal psu, the soft start, and of course the honey badger boards. And the plan was to stick it all in a giant pioneer receiver case I have laying around. I still needed heatsinks, and a transformer. But.... Today.... I scored. $free.99. busted arcam avr600. Power supply was good, and it came with dual heatsinks that are exactly the right size. Tons of standoffs, etc.... So I'm psyched. This will be my first amplifier built, but I have repaired several, and have been studying my *** off of late on this. I'm a desk jockey by day, and have little kids, so this will be an evening project as long as the old German cars are running. I will do my best to take pics, and keep the group updated, and I am sure ask way too many questions. Thanks to those who worked to put this together and make it possible for noobs like me to have a crack at it. Oh yeah, the box of mouser goodies also showed up today. Oh yeah2, that transformer is fricken huge. 1.5kva.
It's prefence. Do you plan to overdrive your amplifier or think that you may enter an overdive condition? If yes, then add the clamp diode. But, you will get increased distortion.
If you are not, then don't put it in.
Best, Sandro
Couple of pics to see what I am working with. I can't believe how perfectly the hb boards fit the heatsink and mount. Will the monster transformer have any drawbacks? I figure it gives me room to expand down the road if I want to add more channels.
I'm thinking some cool meters behind the green glass....
I'm thinking some cool meters behind the green glass....
Attachments
Good answer. I am using horns so it will never be over driven so for now I think I will just leave them out even though I have some BAV20's on the way. I did buy them on Ebay but if one uses some common sense and check who the seller is you can get good original parts. Remember on hard to get parts if it sounds too good to be true it probably is. Also be careful of the China sellers. Some are really good but many sell obsolete components that are fakes.
Boards coming together. Used the mouser bom supplied by ostripper. Need to choose input transistors, was planning on using some mpsa06 I have laying around, as I can't find the mpsa18. I am using 15 zener diode at r18, and transitional miller compensation. Rails will be 59v from the arcam transformer. Any drawback to using a huge transformer? Cause it's frickin huge. 1.5kva.
Attachments
Yeah, it's heavy. So is the steel case. But it looks sharp. The Vcc Vee rails in the arcam were +-59vdc. It came with two other smaller toroidal transformers as well. Not sure what their output is. But those additional transformers, and the huge case will give me expansion options in the future. The speakers I plan on using with it are BIG 8 ohm bang and olufsen MS150 with 10" woofers, 8" mid, 4" phase link, and tweeters, and so far, comparing with some PSB towers, Canton 8", and a couple others, they blow everything I have ever had away. If I was running a 4 ohm speaker, I would want to run lower V rails if I understand correctly.
With a transformer that large, I would still want to run the 40kuf on each rail for the supply yes? The Arcam was running 20kuf on the rails. And I could use those caps, or order 4 more of the same...
With a transformer that large, I would still want to run the 40kuf on each rail for the supply yes? The Arcam was running 20kuf on the rails. And I could use those caps, or order 4 more of the same...
With +/-59V rails you should be able to run 4 ohm speakers. I ran 4 ohm speakers with my HB with +/-63V rails without any problems.
You have a lot of excess power in your toroid so you could easily turn your amp into 5.1. HB at +/-59V rails and 8ohm speakers is happy with a 625VA transformer.
cheers,
You have a lot of excess power in your toroid so you could easily turn your amp into 5.1. HB at +/-59V rails and 8ohm speakers is happy with a 625VA transformer.
cheers,
Last edited:
But there would be a problem with space Please post a link to this as I see your C6 capacitor is different to mine.
P.s I have plenty of mpsa18's if you would like some.
Last edited:
That's a tall order man. I found a link somewhere in the thread, to a project as saved in Mouser, and was able to find it there, an place it in my projects at Mouser. Some items are NLA, or were out of stock so I had to make substitutions.
C6, Specified to be a film capacitor, 220nf 35-100V. 7.5 or 10.0mm lead spacing.
This Wima is what was in the project folder. Mouser p/n for the wima is 505-mks4.22/100/10.
The blue TDK one is what the p/n on the excel BOM I found has. TDK part number. 495-2436-ND
C6, Specified to be a film capacitor, 220nf 35-100V. 7.5 or 10.0mm lead spacing.
This Wima is what was in the project folder. Mouser p/n for the wima is 505-mks4.22/100/10.
The blue TDK one is what the p/n on the excel BOM I found has. TDK part number. 495-2436-ND
Attachments
Last edited:
Thanks. I might try the Wima one as I'm had to remove the THK one as my amplifier was oscillating on startup.
This maybe due to other factors which I'm still investigating and will post my findings once I'm done.
Thank you for time.