Rebuilding 300DC. I love this amp...
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dr*audio
Fish fingers and custard!
I used to have one of these. Great amp. If I make a suggestion for the rebuild. When I got mine it had been modified and some things had been disconnected so I had to re-wire all the wiring to the left channel.
It's been a long time but I remember leaving some extra length of wire and thinking it would now be easier to service than original. Also I used thicker gauge wire than original. So I would suggest rewiring it with 16 AWG wire and leave some extra length to the wires.
It's been a long time but I remember leaving some extra length of wire and thinking it would now be easier to service than original. Also I used thicker gauge wire than original. So I would suggest rewiring it with 16 AWG wire and leave some extra length to the wires.
Salbreth1
Active Member
Thanks guys. It's hard to find the time to post builds. My son is almost 2 and a crazy man! Lots of fun but I'm exhausted...
Thanks for the tip Doc. I didn't plan to upgrade the wire and probably would have if the filters weren't already in. Next time...
This amp is pretty straight forward and easy to work with given the boards unplug and no dual cap to modify.
Well, she's all clean. Power supplies and filters are done. All new semiconductors, zeners, etc.
Thanks for the tip Doc. I didn't plan to upgrade the wire and probably would have if the filters weren't already in. Next time...
This amp is pretty straight forward and easy to work with given the boards unplug and no dual cap to modify.
Well, she's all clean. Power supplies and filters are done. All new semiconductors, zeners, etc.
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Salbreth1
Active Member
Peak indicator board is finished. Everything is out but the 1/4 & 1/2 watt resistors and the fets. The relay was in good shape too so I just cleaned the contacts. I just realized that I only have a couple bf423zl left. These are the subs for the 2sa879s. And there obsolete. I think I'm gona order some of these. All the numbers work, but half the transition freq.
http://www.digikey.com/product-detail/en/diodes-incorporated/ZTX757/ZTX757-ND/92557
http://www.digikey.com/product-detail/en/diodes-incorporated/ZTX757/ZTX757-ND/92557
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KutzlerTrans
Jennie & I with Buddy and Barney.
They are a beautiful looking amp. The Doc is right on. i have had quite a few wires break off and the bean counters that designed this thing sure did a good job cheating the amp out of wire length . that wad of wires stretched under and around the frame towards the front, is cause for new swear words to be invented using comical strung together stuff i didn't even know i knew...
Its good to see you back!
John
Its good to see you back!
John
Salbreth1
Active Member
They are a beautiful looking amp. The Doc is right on. i have had quite a few wires break off and the bean counters that designed this thing sure did a good job cheating the amp out of wire length . that wad of wires stretched under and around the frame towards the front, is cause for new swear words to be invented using comical strung together stuff i didn't even know i knew...
Its good to see you back!
John
LMAO! Yeah it's pretty tight there. Going with screw terminal filter caps added a little length. That helped. Could be worse, if it were solid strand wire half would have broke off just removing the amps.
Rocko81
Super Member
Ugh I remember that happening when I changed a bulb in my Pioneer Spec 2. Silly sold core wiring, simple fix once I found out what wire it was.
nj pheonix
Lunatic Member
Am I mixing you up? You're the guy that rebuilt the jigsaw puzzle Marantz receiver 2500? Maybe) you lived in (around ) philly, but you were moving? Somewhere in NE?
If you got that one together this one should be a breeze. Oh, BTW, enjoy them when they're little. They get big fast!
If you got that one together this one should be a breeze. Oh, BTW, enjoy them when they're little. They get big fast!
Salbreth1
Active Member
Thanks, this one is in tact. What a shame it's being parted out. I'd like to get one of those too.
Salbreth1
Active Member
Yes that's me. Ive recently moved to Vermont. And I hear ya. I can't believe how big he is now! We're already talking about preschool. What the hell happened!!?
Anyway. My order should be hear Monday. I'll have this guy finished soon.
Sal
Salbreth1
Active Member
Amplifiers are finished. I stripped everything except for resistors 1/2 watt and under and the dual fet. As usual I used Silmic ll and Nichicon FG lytics and Panasonic metalized poly fims. Vishay metal film resistors. All new fairchild semiconductors, zeners, bjts, ect. A new Bourne's multiturn pot to make life easier. This thing is gonna sound great.
To sub the obsolete BF423z I ended up using ZTX957. These match the transition frequency and higher gain of the original 2sa879r.
Time to put things back together!
To sub the obsolete BF423z I ended up using ZTX957. These match the transition frequency and higher gain of the original 2sa879r.
Time to put things back together!
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Salbreth1
Active Member
Thanks. I finished it Saturday night and been listening since. This thing is sounds great!
I just finished a model 16 (100+100) and a 250 and in my humble opinion the 300dc takes the cake. I know these are very different amps, but it cool to do some critical listening with all 3.
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nj pheonix
Lunatic Member
Nice!
Thanks for sharing the project and the review!
Thanks for sharing the project and the review!
