BlackScholes
Active Member
Edit: After 2+ years, I'm finally tackling these receivers. After restoring dozens of items out of my collection, I can say that I know a lot more now than I did two years ago so I'll be making updates to the below summary as well as additional posts to the thread. Before I regained my sanity, I had accumulated 10+ Marantz 18s and 5 Marantz 19s. I'll keep two of each and the rest will be sold.
Since the two units are so similar and I have at least a couple of each, I wanted to start a new thread to go through my progress in bringing them back to original specification (and maybe even better). I'd like for this to one day be the definitive guide for one or both of these receivers.
Summary
I'm a past member here who has decided to start a new account given my last account was my full name and the internet has changed. I think the last time I spent a lot of time posting here was 2014. Since then, my collection of gear has narrowed in focus and I'm looking to learn more about electronics by recapping a couple of boards I have in parts units and going from there with actual functional units. When I think about my restorations, I do my best to look through the lens of the team who designed the 18 and chose the components for it since I simply don't see any bit of cost-cutting in the 18, but there are some obvious cuts in the 19. If the 18 were built today with the same type of components of the original but being up to today's standard, what parts would be used? Since nearly all of the parts in the 18 are of the same or better quality than the 19, I will apply the same parts used in the 18 to the 19 to the extent I can. I've become pretty obsessed with both models and hope this thread helps you and helps me get all of my ideas out there.
Test Equipment (updated 01/06/23)
Using the Marantz 19 service manual as guide, I purchased/already own the following:
Marantz 18 vs Marantz 19
I've listened to and examined both the 18 and 19 along with studied both and can summarize the pros and cons of each fairly confidently:
So far, I've cleaned/restored a tone board from one of the model 18s and have rebuilt a power supply on one of the 19s I have. Below, I'll summarize my findings with each board and include any questions I might have. Then I'll update the section with the answers as I receive them.
Since the two units are so similar and I have at least a couple of each, I wanted to start a new thread to go through my progress in bringing them back to original specification (and maybe even better). I'd like for this to one day be the definitive guide for one or both of these receivers.
Summary
I'm a past member here who has decided to start a new account given my last account was my full name and the internet has changed. I think the last time I spent a lot of time posting here was 2014. Since then, my collection of gear has narrowed in focus and I'm looking to learn more about electronics by recapping a couple of boards I have in parts units and going from there with actual functional units. When I think about my restorations, I do my best to look through the lens of the team who designed the 18 and chose the components for it since I simply don't see any bit of cost-cutting in the 18, but there are some obvious cuts in the 19. If the 18 were built today with the same type of components of the original but being up to today's standard, what parts would be used? Since nearly all of the parts in the 18 are of the same or better quality than the 19, I will apply the same parts used in the 18 to the 19 to the extent I can. I've become pretty obsessed with both models and hope this thread helps you and helps me get all of my ideas out there.
Test Equipment (updated 01/06/23)
Using the Marantz 19 service manual as guide, I purchased/already own the following:
- 2x HP 8903B Audio Analyzer
- HP 3456A Digital Voltmeter (because why not? also have Fluke 117)
- HP 130C Oscilloscope
- Superior Voltbox (Fancy Variac)
- WD-766A Digital Wattmeter
- 8 & 16-ohm dummy loads
- various probes and cables
- and more gear purchased since 11/20
Marantz 18 vs Marantz 19
I've listened to and examined both the 18 and 19 along with studied both and can summarize the pros and cons of each fairly confidently:
Marantz 18
Current ProgressPros:
Marantz 19- Build quality exceeds the 19. The faceplate is cast iron. Top and bottoms covers are heavier. Glass dial. Better workmanship. No flimsy power supply board.
- Higher quality parts overall.
- Easier to keep the original look.
- Slightly less expensive than the 19.
- HF winding in the transformer is prone to failure rendering the scope useless.
- Power supply and scope are more difficult to access and work on.
- To most, design is dated compared to Model 19.
- Less powerful than the Model 19 (but we'll see if that holds post restore).
- Dial lettering falls off (seriously, do not attempt to clean or touch).
- Most heat sinks are faded.
- Early units had a host of issues including power switch failures.
- Tuner has weak amplification limiting station availability.
Pros:
- Higher power (50 vs 40 watts/channel @ 8 ohms)
- Design sets the stage for all of the following classic receivers from the 1970s. Beautiful.
- Anodizing & paint quality seems to be better than 18.
- Some boards are easier to access and service.
- Some transistors have sockets where they can simply be pulled out and reinserted.
- Service manual is amazing.
- Transformer seems less prone to failures.
- Cheaper parts were used and some cost cutting is apparent.
- Some signs of poor workmanship in terms of soldering.
- Impossible to recap and keep original looking unless restuffing caps.
- Confines of power supply board & cover limits component choices.
- Power supply board is prone to burn marks and is very brittle.
- Some design choices were clearly made to make it easier to assemble the unit, but not for improved sound.
- The black badge.
- Faceplate was not meant to be disassembled, meaning the tinted plastic window cannot be easily separated from the aluminum. So, if it's badly scratched, you're SOL. Super cheap.
So far, I've cleaned/restored a tone board from one of the model 18s and have rebuilt a power supply on one of the 19s I have. Below, I'll summarize my findings with each board and include any questions I might have. Then I'll update the section with the answers as I receive them.
Tone Board
Even 53 years later, there are film caps available that are direct, drop in replacements for the ten you'll see I've replaced. No lead bending required. In addition, I replaced the four 100uf/mfd - 6vdc electrolytic capacitors. While those electrolytic caps tested fine, they all had levels of visible leakage/crustiness. I wanted to keep the original size & appearance so I replaced them with four tantalum capacitors. Three questions on this board:
Even 53 years later, there are film caps available that are direct, drop in replacements for the ten you'll see I've replaced. No lead bending required. In addition, I replaced the four 100uf/mfd - 6vdc electrolytic capacitors. While those electrolytic caps tested fine, they all had levels of visible leakage/crustiness. I wanted to keep the original size & appearance so I replaced them with four tantalum capacitors. Three questions on this board:
- Is there any reason to replace the 6800pf or the 220pf polystyrene capacitors? These are the small silver caps.
- For the eight transistors, there are two part numbers (four of each):
- 34-1008: I see NTE234 was once a sub according to info I found for the 19, but this transistor doesn't seem to be available. Looks like a 2N5401 works, but is there a better substitute?
- 34-1010: 2N4401, 2N5769, 2N3904? Any others that are better?
- Anything else I should do while I have these out?
Last edited:
