Marantz 300DC to restore

[Giovanni68]

Got a Marantz 300DC locally, haven't been used since ages, I guess caps are gone to start with, wondering if worth the pain attempting a repair.

Attaching a few pics of the interiors, outer cover has some rust and wondering if it can also be restored to like new, only part which seems gone is the rear voltage selector, maybe just the sealing, any hint is welcome

Grazie


Giovanni

 

[Lavane]

They're nice amplifiers. If one came my way I would be all over repairing it to get it to work, then fully restore it. What's wrong with it? No sound at all coming out of both channels? Has the voltage selector been removed, or was one just never installed? I'm not really familiar with the DC300, but some Marantz models.come with ot without voltage selectors. Some are just wired for 120v only.

 

[Giovanni68]

I didn't even dare plugging it into the AC outlet, I rather have somebody skilled to check it out and eventually repair, for sure caps have to be swapped, as far as I read also the meters lights have to be swapped with LEDs to begin with, the rear shows the voltage selector seal to be replaced/fixed but overall I guess it's worth an attempt.

I have a very skilled friend here who also fixed a solid state FirstWatt clone for me, he asked me to show pics of the amp to figure if he wants to attempt a repair, crossing fingers otherwise I will have to ship it abroad to fix but I also first hear your opinions re the amp.

At this moment in time I listen to JBL L220 with KT88 tubes, the FirstWatt F4 I had built on purpose has not enough swing off the AR SP9 preamp (needs a 20v output preamp to work 100% potential), source being a meh Beresford Caiman DAC (first thing to swap once I have enough cash to spend onto stereo!) which serves a MacMini to stream lossless music and a Sony ES player which sounds way better than the Beresford DAC, it would be interesting to listen to the JBLs with a powerful solid state amp from their era.

 

[Lavane]

I didn't even dare plugging it into the AC outlet, I rather have somebody skilled to check it out and eventually repair, for sure caps have to be swapped, as far as I read also the meters lights have to be swapped with LEDs to begin with, the rear shows the voltage selector seal to be replaced/fixed but overall I guess it's worth an attempt.

I have a very skilled friend here who also fixed a solid state FirstWatt clone for me, he asked me to show pics of the amp to figure if he wants to attempt a repair, crossing fingers otherwise I will have to ship it abroad to fix but I also first hear your opinions re the amp.

At this moment in time I listen to JBL L220 with KT88 tubes, the FirstWatt F4 I had built on purpose has not enough swing off the AR SP9 preamp (needs a 20v output preamp to work 100% potential), source being a meh Beresford Caiman DAC (first thing to swap once I have enough cash to spend onto stereo!) which serves a MacMini to stream lossless music and a Sony ES player which sounds way better than the Beresford DAC, it would be interesting to listen to the JBLs with a powerful solid state amp from their era.

I sold off almost all the Marantz gear I had and switched to tubes.
I have a couple parallel Push Pull KT-88 VTA M-125 mono blocks for 125 watts each.
All my other tube amps I've built are 3.5wpc to 35wpc. KT-88's are nice sounding tubes. What KT-88 amp do you have?
I still have a Marantz model 140 power smp with meters I restored.
I used cool blue LED's for the meters in it. You have to angle them down around a 45° angle to be able to shine on the meters.

 

[quadmatrix82]

These are really nice amplifiers, if you or you’re friend is handy with electronics, soldering etc it’s worth restoring yourself

As a minimum I’d recommend a recap, replace the differential transistors and relays and upgrade the lamps to warm white led

For filter caps Nichicon gold tune had a direct replacement when I did mine

Goodluck with it

 

[Kodaline]

Giovanni, I sent my 300DC to Arnel Bautista to fix and it is very good now. He is in Virginia if you want to send it off and are in the USA/That region.

 

[Giovanni68]

I sold off almost all the Marantz gear I had and switched to tubes.
I have a couple parallel Push Pull KT-88 VTA M-125 mono blocks for 125 watts each.
All my other tube amps I've built are 3.5wpc to 35wpc. KT-88's are nice sounding tubes. What KT-88 amp do you have?
I still have a Marantz model 140 power smp with meters I restored.
I used cool blue LED's for the meters in it. You have to angle them down around a 45° angle to be able to shine on the meters.

I have an Aeron AP890, you won't find much about it on the web, it's an Italian project (I'm an Italian living in Italy but looking to at least move away for a while since this country has not much to offer any longer but won't contaminate the thread with such stuff) produced in China, classic KT88 push pull rated at 50W with some heavy transformers, it weight a little more than 50 pounds and I like its sound; on the other hand I wish the FirstWatt F4 clone would drive the old JBL L220 but the preamp has not enough voltage to drive the FirstWatt which is a buffer and requires almost twice the output the AR SP9 can get.

I got this Marantz off a friend, it sure needs some care, asking a local very skilled guy if he feels approaching this restoration, crossing fingers he would otherwise I have to ship somewhere in Italy to figure it out which would add to the expense, I have enough amps, if I manage to restore this I might either keep or probably try and sell as I am short on space but it seems like having good reviews so I am curious to listen to it and thank you for the hint about LEDs for the meters!!!

 

[Giovanni68]

These are really nice amplifiers, if you or you’re friend is handy with electronics, soldering etc it’s worth restoring yourself

As a minimum I’d recommend a recap, replace the differential transistors and relays and upgrade the lamps to warm white led

For filter caps Nichicon gold tune had a direct replacement when I did mine

Goodluck with it

Grazie @quadmatrix82 I hope I can have it restored as I am curious to hear how a solid state amp contemporary to my L220 would sound, had I the funds I'd be on two tube mono blocks but it is what it is...

Grazie

 

[Giovanni68]

Giovanni, I sent my 300DC to Arnel Bautista to fix and it is very good now. He is in Virginia if you want to send it off and are in the USA/That region.

A bit out of reach ;-) but thanks for your suggestion