Marantz eighteen (18) receiver questions

[monkboughtlunch]

Since there's no loudness feature on the 18, would that open up the number of aftermarket volume pot options (i.e. no loudness tap required on the pot)?

 

[monkboughtlunch]

Would any of these three be a good aftermarket replacement volume potentiometer for the OEM part in the Marantz Model 18? Click links to view datasheets. Which would have the best sound quality, tracking, and longevity? Would any be a drop in fit that could be soldered to the board like the original OEM part?

Cosmos Tocos Potentiometer RV24YG 250k

Precision Electronics Corporation KKA2541S28 250k

Alps Blue Velvet 250k stereo, RK27112

 

[monkboughtlunch]

Does anyone know the bulb # for the stereo indicator light on the Marantz 18? If so, is there a corresponding LED replacement available for the bulb? I will eventually change out the glass or take it off to clean it, and when I do I want to change the indicator light at the same time to a long-lasting LED (so I won't have to go through the hassle of pulling the glass off again at some point down the road when the original bulb fails).

If anyone has the their glass off, could they pull out their stereo indicator bulb and see what number the bulb is? It appears smaller than the two #1847 bulbs used it illuminate the glass. The owner's manual doesn't indicate the bulb used for the stereo indicator. Thanks!

 

[txturbo]

It's a NE2H neon panel indicator lamp with a flying lead. It has a very long life so you may be able to get by with a new one of the same type. If you switch to LED you need to find an LED panel indicator that works off of AC. What does the face of your bulb look like? Does it have a star in it?

I think the original is similar to the one in the back that comes on when the FM mutes.

Did you order new glass from Radio Daze?

 

[monkboughtlunch]

It's a NE2H neon panel indicator lamp with a flying lead. It has a very long life so you may be able to get by with a new one of the same type. If you switch to LED you need to find an LED panel indicator that works off of AC. What does the face of your bulb look like? Does it have a star in it?

I think the original is similar to the one in the back that comes on when the FM mutes.

Did you order new glass from Radio Daze?

Thanks! Does the lead require any soldering or can it be directly plugged in? The lens (not the bulb) of my unit is orange and does not have the star.

I've seen pictures of other Marantz 18s in which the stereo indicator lens is clear (not colored orange like mine) and with a star imprint. In this case, I would guess the neon lamp provides the color. What color was the neon when lit up on the models with the clear star? For example, did the neon lamp illuminate orange or red? Were the 18s with the clear star lens early or late production? Also, was the star just silkscreened on the lens or was it actually etched into the lens?

Another oddity I've observed over production runs is that the black backdrop of the FM dial appears to have a rough texture on some units and is totally smooth on other units. Does one backdrop make it easier to read the dial vs the other? My unit is a smooth black backdrop (no textured pattern).

Thank you!

 

[txturbo]

Thanks! Does the lead require any soldering or can it be directly plugged in? The lens (not the bulb) of my unit is orange and does not have the star.

I've seen pictures of other Marantz 18s in which the stereo indicator lens is clear (not colored orange like mine) and with a star imprint. In this case, I would guess the neon lamp provides the color. What color was the neon when lit up on the models with the clear star? For example, did the neon lamp illuminate orange or red? Were the 18s with the clear star lens early or late production? Also, was the star just silkscreened on the lens or was it actually etched into the lens?

Another oddity I've observed over production runs is that the black backdrop of the FM dial appears to have a rough texture on some units and is totally smooth on other units. Does one backdrop make it easier to read the dial vs the other? My unit is a smooth black backdrop (no textured pattern).

Thank you!

The ones with the star light up orange.

I never changed mine because the chance of failure is almost zero. My sister had an old GE flip clock with the same type of lamp running non stop for 40 years then it quit. I though it was bad but it was the inline resistor. I bet the lifetime is close to an LED.

If you do change it I would just put the same type in.

I am not sure if the star is silkscreen or etched. I do like the star better than the standard one.

All of mine have kind is a black crinkle paint for the background of the dial.

 

[monkboughtlunch]

After installing the Comet Pinball LEDs for the side illumination, I did notice that the neon stereo indicator light seems to flicker very rapidly (hard to notice unless you look closely)... Any ideas one what may cause that?

 

[txturbo]

After installing the Comet Pinball LEDs for the side illumination, I did notice that the neon stereo indicator light seems to flicker very rapidly (hard to notice unless you look closely)... Any ideas one what may cause that?

Not really... What happens if you remove the LED lamps?

 

[monkboughtlunch]

If one recaps the power supply, should they use the exact same values as the original caps (both microfarads and voltage rating)? Or should either rating be increased to a higher value? What are the pros/cons of increasing the values?

 

[txturbo]

If one recaps the power supply, should they use the exact same values as the original caps (both microfarads and voltage rating)? Or should either rating be increased to a higher value? What are the pros/cons of increasing the values?

You can go larger in voltage or mf however I try and keep the values as close as possible. The higher voltage ratings are typically never an issue. If you increase the cap values dramatically it can stress the rectifier diodes on start up.

On the 18 the caps are all axial, limiting your choices. It's a bit trickier to install them as well. Do you have a de-soldering system?

 

[monkboughtlunch]

5: Practicaly sur that there were about 7,000 of models built between October 67 and June 1970.

I was wondering if it's possible figure out the approximate manufacturing date of Model 18s based on serial numbers.

I've read that Marantz began serial numbers starting at 1000. So the first unit created would be 1001. If there were 7,000 models produced, that would mean serial numbers go up to approximately 8,000.

What's the highest serial number of an 18 anyone has seen? Low 8000s?

The earliest ads for the 18 appear in Oct. 1967. A Dec. 1967 Electronics World article states that the magazine didn't review the 18 for a receiver shootout because they received an engineering prototype from Marantz, not an actual production model. Unclear if that means it wasn't yet in production when the article was written (presumably in November 67).

I ran a quick search on the American Radio History website (which has an index of audio old magazines), and earliest mention I've found of the successor model, the Marantz Model Nineteen (19), in print advertisements is in the May 1970 issue of High Fidelity.

Do you think production of the Model Eighteen might have ended a earlier than June 1970 if they were beginning production of the 19? Or do you have data that shows June was the final production end?

If we assume production of the Model 18 began approximately in Sept. 1967 (just before the first print ads) and finished around April 1970 (the month before the 19 was first announced), that is 32 months and an average of 219 units produced per month (assuming production was steady throughout the run).

For 7000 units produced, that might translate to the below serial number ranges per month. Thoughts on if these production dates are accurate? Anyone have original sales receipts for their units to confirm? Also, what month and year did Marantz shift production from NY to California? I think all the 18s were made in NY. Were any of the 19s made in NY -- or were the earliest 19s produced in California?

Possible Marantz Model Eighteen production dates:

(Note: the below is only my best guess and could be inaccurate.)

Sep-67: 1001-1219
Oct-67: 1220-1438
Nov-67: 1439-1657
Dec-67: 1658-1876
Jan-68: 1877-2095
Feb-68: 2096-2314
Mar-68: 2315-2533
Apr-68: 2534-2752
May-68: 2753-2971
Jun-68: 2972-3190
Jul-68: 3191-3409
Aug-68: 3410-3628
Sep-68: 3629-3847
Oct-68: 3848-4066
Nov-68: 4067-4285
Dec-68: 4286-4504
Jan-69: 4505-4723
Feb-69: 4724-4942
Mar-69: 4943-5161
Apr-69: 5162-5380
May-69: 5381-5599
Jun-69: 5600-5818
Jul-69: 5819-6037
Aug-69: 6038-6256
Sep-69: 6257-6475
Oct-69: 6476-6694
Nov-69: 6695-6913
Dec-69: 6914-7132
Jan-70: 7133-7351
Feb-70: 7352-7570
Mar-70: 7571-7789
Apr-70: 7790-8008

Here's an image of the Oct. 1967 print ad.

 

[monkboughtlunch]

You can go larger in voltage or mf however I try and keep the values as close as possible. The higher voltage ratings are typically never an issue. If you increase the cap values dramatically it can stress the rectifier diodes on start up.

On the 18 the caps are all axial, limiting your choices. It's a bit trickier to install them as well. Do you have a de-soldering system?

Which brand/s of capacitors do you recommend for quality and longevity?

 

[monkboughtlunch]

You can go larger in voltage or mf however I try and keep the values as close as possible. The higher voltage ratings are typically never an issue. If you increase the cap values dramatically it can stress the rectifier diodes on start up.

What approximate percentage increase in microfarads would stress the diodes?

 

[monkboughtlunch]

Has anyone tried vintage AR speakers (such as the 4 ohm AR-3, AR-3A or 8 ohm AR-2A, AR4x etc) with an 18? If so, thoughts on the synergy? The general wisdom these days is you need a lot of power to run AR speakers. But the original spec sheets AR published back in the day recommend 25 wpc RMS for the 3A and 15 WPC for the 4x etc. In some of the old magazines, I've even read that when they tested the 18, they paired it with AR-3As.

Anyone tried Klipsch Heresy (much more efficient than AR) with an 18? Thoughts on synergy?

 

[GrantMchls]

Can any please tell me how to remove the stereo indicator light and holder from the front plate holding it? This is the plate behind the tuning indicator glass. The plate holding the stereo indicator is covered with crude of some sort and needs to be thoroughly cleaned and possibly painted. I have it separated from the receiver except for the light and cannot figure out how to remove the light from the plate.

 

[txturbo]

Can any please tell me how to remove the stereo indicator light and holder from the front plate holding it? This is the plate behind the tuning indicator glass. The plate holding the stereo indicator is covered with crude of some sort and needs to be thoroughly cleaned and possibly painted. I have it separated from the receiver except for the light and cannot figure out how to remove the light from the plate.

That’s not crud, it’s mat crinkle paint, you do not want to remove it.

 

[GrantMchls]

It's not black anymore, it's white and speckled and makes the dial glass look heavily mildewed. The glass is fine, the white mildewy stuff is on the paint. Perhaps, it is mildew and will come off with light mildew remover. Even so, I would like to remove the plate if possible rather than attempt to clean the panel on the unit. The only thing preventing removal is the stereo light.

 

[GrantMchls]

txturbo, I forgot to thank you for your reply. There is a chance that due to the white stuff on the paint, I might have assumed that it caused the crinkle and sanded the plate before repainting it. Don't know, but I'll try mildew remover first. Can you help with the stereo light issue?.

 

[RV59]

To remove this plate, you have to unsolder the stereo light wires.
Then you remove the glass.
Then remove the small metal plate behind the stereo light with a small screwdriver.
Protects the plastic skylight for the scope with a small sheet of paper before painting.
I repainted it in satin black.

Don't try to clean the plate with sandpaper, otherwise the small balls sticking to the plate will go away.

 

[GrantMchls]

I was trying to avoid unsoldering the stereo light, but didn't see any way around it. Thank you for confirming my suspicions. I was hoping there was another way. Oh well.