Restoring Marantz Imperial 6 Speakers

wisnowski1

So, I recently found a pair of vintage Marantz Imperial 6 speakers at the thrift. Picked the pair up for 20 bucks. They produce sound just fine, but it's a bit muffled. I was hoping to get some kind of direction to getting these back to their former glory. I don't have any prior experiance with working on electronics. Should I get them recapped? Refoamed? Replace the woofers? I want to get them sounding like they did back in the seventies. Also, if i were to pay someone for these things what kind of rough estimate do you have for cost.

pitdogg2

well first thing is check the foam surrounds. If they feel sticky, soft and very pliable it may be time. I would think that maybe there were done at some time as foam especially older foam didn't last much past 15-20yrs max. All tweeters working? The xo components are way past life at this point it would be wise to invest in new for that area. Really depends on how much you wish to invest in them.
Welcome to club Polk.

cnh

Welcome to Club Polk!

Pretty sure your surrounds are a doped cloth so no need to replace those? The tweeter is a phenolic one so no foam there either. Sounds like you probably just need some new caps.

I don't know what the values are there. But the crossover on those speakers should be very very simple. Nothing too involved. I bet it's just a one cap or so.

There is probably a lot more info about these on audiokarma.org You should take a look over there.

And also, our mhardy may know something more. The Imperial series was Marantz's attempt to compete in the speaker arena especially with JBL with the larger Imperial 7s.

I have a set of Rogers Sound Labs that were made with extra parts that were used in the Imperial 7s. The drivers are all the same but I believe there is an actual crossover inside them, unlike what was going on with the 7s. Supposedly, the 6s (the smaller) speaker are actually better than the 7s which had neither a real LOW end nor much above 10 or 12 Khz up top?

cnh

mhardy6647

... oh, yeah, as if I need encouragement to post to a thread like this! ;-)

The Imperial Six is a somewhat legendary project - at least, since the advent of the interwebs ;-)
http://www.epinions.com/review/imperial-6-speaker/content_607406034564?sb=1
http://www.audiohistory.com/files/documents/marantzhistory.pdf

Bart Locanthi is the connection from JBL through Marantz to Pioneer (TAD); from JBL L-100 through Pioneer HPM-100.
Interestingly, in a "Kevin Bacon" kind of connection - the L-100 (or, more accurately, the studio monitor variant) was designed to compete with the then-ubiquitous Altec Duplex in studio monitor applications -- and JBL ultimately and decisively took that market away from Altec.

... and I, of course, am an Altec Duplex kind of guy ;-)

DSC_8961 by mhardy6647, on Flickr

codyc1ark

Aaaaand this is why the two previous posters are my favorite. Keep it up guys.

mhardy6647

... favorite what? ;-)

codyc1ark

mhardy6647 wrote: »

... favorite what? ;-)

Oh, the man love I would make to your audio knowledge. :eek:

wisnowski1

hey, thanks everyone! I'm a total novice here... and I'm assuming xo components are compacitors for recapping? how do i know which xo components to buy? is there a certain brand or type i should lean towards? is the whole process just removing the old one and soldering in the new one?

I appreciate the input very much.

halo71

codyc1ark wrote: »

Oh, the man love I would make to your audio knowledge. :eek:

hehe...sig material there!


Marantz HD88's are on my bucket list of speakers to have. My Dad had a pair when I was a kid and I remember them being great speakers. Yeah I know...unrelated to your question. But it made me remember the HD's. Oh and welcome to the forum!

mhardy6647

wisnowski1 wrote: »

hey, thanks everyone! I'm a total novice here... and I'm assuming xo components are compacitors for recapping? how do i know which xo components to buy? is there a certain brand or type i should lean towards? is the whole process just removing the old one and soldering in the new one?

I appreciate the input very much.

Yes, new capacitors in the speakers' crossovers (that divide the low and high frequencies between the woofer and the tweeter) are - for a speaker that old - virtually guaranteed to improve their sound.

Are you sure each speaker's tweeter is working? If not, the sound might be quite muffled indeed!

The other thing I don't know (and am too lazy to look up!) is whether there's a tweeter level control on the Imperial Six. If so, those controls (which are most likely a type of paralleled potentiometers called an "L-pad") may be noisy/dirty (oxidized). If there are such level controls... if you "fiddle" with them -- to use the technical term ;-) -- you might get the tweeters to work and/or be louder.

wisnowski1

Attachment not found.Attachment not found.
this is what i found when i opened it up. i had to split the picture up in 2 because the forum wouldn't let me add pictures over 500 bytes.
from just putting my ear against the tweeters I'm guessing they're both not working. thanks hardy.

drumminman

Attachments links not working. Try resizing pics.

Imperial 6's were my very first speakers - fond memories. Don't remember them having L-pads, so mine must have been an earlier version. Bought them new in 1972.

Found this Xover pic on ebay: http://www.ebay.com/itm/Marantz-Imperial-6-G-8-ohm-2-Way-Speaker-Crossover-Pair-/380891606750?pt=Vintage_Electronics_R2&hash=item58aee8aede

wisnowski1

mhardy6647 wrote: »

Yes, new capacitors in the speakers' crossovers (that divide the low and high frequencies between the woofer and the tweeter) are - for a speaker that old - virtually guaranteed to improve their sound.

Are you sure each speaker's tweeter is working? If not, the sound might be quite muffled indeed!

The other thing I don't know (and am too lazy to look up!) is whether there's a tweeter level control on the Imperial Six. If so, those controls (which are most likely a type of paralleled potentiometers called an "L-pad") may be noisy/dirty (oxidized). If there are such level controls... if you "fiddle" with them -- to use the technical term ;-) -- you might get the tweeters to work and/or be louder.

One last question i think... i notice in the service manual that if the tweeters aren't working the troubleshooting suggestion is to check the resistors. Should i replace the resistors along with the capacitors? or are the tweeters probably not functioning just due to age? also, any recommendations for capacitors? these are the ones i was gonna go with...
https://www.parts-express.com/dayton-audio-dmpc-68-68uf-250v-polypropylene-capacitor--027-424

mhardy6647

Chances are - if the tweeters aren't working and the crossover parts are (all) OK - the tweeters' voice coils are burned out (due to abuse).
The resistors could be bad; it's not likely, but it is certainly possible.
Do you have a voltmeter?
If so, you can check the voice coils for "continuity" and you can check the resistors, too.

wisnowski1

thanks for the help. hopefully ill have everything done by mid next week. refinishing the cabinets and grills, changing caps and tweeters. ill post pics when done.

mhardy6647

The Dayton capacitors are very reasonable choices I'd opine - doesn't PE have a fairly hefty minimum order, though?

pitdogg2

mhardy6647 wrote: »

The Dayton capacitors are very reasonable choices I'd opine - doesn't PE have a fairly hefty minimum order, though?

No but the shipping can be a killer. Buy 7.00 in parts spend 10.00 for shipping....you want to make double sure you have all you need because to go back for one item can be prohibitively expensive.

mhardy6647

yeah - I like to stock up (on whatever...) when I have to place an order :-)

wisnowski1

mhardy6647 wrote: »

The Dayton capacitors are very reasonable choices I'd opine - doesn't PE have a fairly hefty minimum order, though?

between two tweeters and two capacitors it cost $43 and $12 for shipping.

bigaltx24

You should try cleaning the switch with Deoxit.