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Post by vipertblck on May 21, 2018 11:50:34 GMT
model 100BL. amp has all new caps, tubes work and transformers appear to be original. just picked this box up. sounds good and has decent volume, but have heard these box's play louder. was suggested to change the whole needle assembly, which I believe is the cartridge they call it, the needles, and the "plug" that goes into the mechanism. in online research I found it should be checked with an ohm meter; just what I've found, a good one is about 1.6-1.7K. is this correct?
in testing mine in the box I pulled it out, placed my leads on the 2 prongs sticking out the bottom of it (there's only 2); I got about 0.4K. had another cartridge assembly my dad has around; it tested about the same (0.39k). I don't believe either cartridge is a black or red head. they are what looks to be an aluminum head on them with yellow inserts (needles) on each side that are replaceable.
just trying to figure out what these numbers mean that i'm measuring. thanks in advance |
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Post by Ron Rich on May 21, 2018 13:59:07 GMT
One--don't believe what's on the "internet" --resistance readings on a magnetic cartridge are somewhat meaning-less. All Seeburgs used on 45 RPM units were magnetic--starting with the model B, Thru the models G-W, the cart was a black colored unit--after that it was a "red" colored unit.
You will need to determine what someone has installed into you unit, and go from there. "Volume" is mostly "controlled" by the needle used !If you wish to purchase a copy of my "Seeburg Mechanism Guide",in which I documented ALL Seeburg cartridges used, contact me off forum. Ron Rich
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Post by robnyc on May 21, 2018 14:34:30 GMT
OK, "viper". you have an 345 cart (used from 1966 -up) in place of the original redhead mono. That cart has a much lower output than the original type. These were subbed to allow the use of stereo records without damage and lower tracking weight (if properly balanced).
"in online research I found it should be checked with an ohm meter; just what I've found, a good one is about 1.6-1.7K. is this correct?"
That would be correct range for a mono redhead. The cart you have is approx 460 ohms per channel. In some modifications the two channels of the cart are wired in series to boost output a bit closer to the original cart. That may have been done in the terminals at the front of the tonearm assembly, and that is why you see a much lower reading when measuring the cart outside the machine. However, the reading you get is still a lot higher than just the doubling (approx 900ohms) that is expected. I'd recheck the connections and your way of connecting the meter.
In any case, that cart is going to yield lower output than the original preamp design called for.
RobNYC
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Post by Ron Rich on May 21, 2018 16:49:11 GMT
Rob,
There's no telling which "replacement" he has--the 345 mono Pickerings measure in the neighborhood of .9. He could have any one of many aftermarket carts, and needles. "Yellow" needle, plastic bases, were produced for the red-heads, by Pickering, and are still around today, in an aftermarket offer !
Ron Rich
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Post by vipertblck on May 21, 2018 17:10:04 GMT
OK, "viper". you have an 345 cart (used from 1966 -up) in place of the original redhead mono. That cart has a much lower output than the original type. These were subbed to allow the use of stereo records without damage and lower tracking weight (if properly balanced).
"in online research I found it should be checked with an ohm meter; just what I've found, a good one is about 1.6-1.7K. is this correct?"
That would be correct range for a mono redhead. The cart you have is approx 460 ohms per channel. In some modifications the two channels of the cart are wired in series to boost output a bit closer to the original cart. That may have been done in the terminals at the front of the tonearm assembly, and that is why you see a much lower reading when measuring the cart outside the machine. However, the reading you get is still a lot higher than just the doubling (approx 900ohms) that is expected. I'd recheck the connections and your way of connecting the meter. In any case, that cart is going to yield lower output than the original preamp design called for. RobNYCThanks! Ill take pics of the two cartridges i'm playing with, as well as how I hookup my meter, and post that tonight. I'm basically bench testing the cartridges on the table. Should I be checking resistance in the box itself, where the cartridge plugs into? You mentioned modification to increase output in the tonearm assembly. Tonearm is where the cartridge actually plugs into, correct?
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Post by vipertblck on May 21, 2018 17:15:36 GMT
i'm basically trying to figure out if I have a good cartridge assembly or not, in relation to my volume issue. i'm new to all this and learning everything still, so it's a bit slower process for me. |
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Post by vipertblck on May 21, 2018 22:41:16 GMT
  
Here's what i'm dealing with and the method I have for measuring the ohms. is this even an accurate test to do on cartridge assemblies? Sorry if some of these posts/questions are stupid; this is all new to me. I rather get something going myself and make the attempt before callin and paying someone.. |
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Post by Ron Rich on May 21, 2018 23:47:53 GMT
What you have are two Pickering "340" style STEREO cartridges, and two different "adapters" made by ??, that are supposed to equal the older mono style carts. I have yet to see an adapter, that works as well as the original (in this case) blackhead cartridge. Ron Rich
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Post by vipertblck on May 21, 2018 23:51:51 GMT
so would it be safe to assume that these cartridges I have would limit the volume issue i'm experience, when compared to a blackhead or redhead?
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Post by Ron Rich on May 22, 2018 0:00:45 GMT
No, not necessarily--that would depend on several factors--What is the stylus pressure set at--who "built" the adapter--was it done correctly, for which needle was it designed, and which needle is installed ?? Ron Rich
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Post by robnyc on May 22, 2018 0:12:34 GMT
so would it be safe to assume that these cartridges I have would limit the volume issue i'm experience, when compared to a blackhead or redhead? Going by the impedance on the red adapter only one channel is connected. If that adapter is sealed there is nothing that can be done. Both devices you have are really not going to get good results. Connecting only one channel prevents reducing distortion by connecting the two channels in parallel thus phase-cancelling a lot of the "mush" on worn records. Second, the output is always going to be low -especially with other than original Pickering-Seeburg styli. So, at this point you have the typical problem with these old machines. Option one: get either a redhead or blackhead cart. Option two: get a 345-03D retro cart. This will require either adding weight or cutting down the counterweights to balance it. The sound quality will be the best possible (i've used these connercially for 26 years) but it will still be somewhat lower in level unless the preamp is modified and the the original styli are no longer being made. Option three: replace the existing tonearm with the later stereo arm. We can go into that if you are interested. there is a fair amount of work involved. None of these are cheap, simplest is option one. Otherwise, leave as is. Hopefully the arm is balanced and not chewing up the records. RobNYC |
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Post by vipertblck on May 22, 2018 11:27:11 GMT
Going by the impedance on the red adapter only one channel is connected. If that adapter is sealed there is nothing that can be done. Both devices you have are really not going to get good results. Connecting only one channel prevents reducing distortion by connecting the two channels in parallel thus phase-cancelling a lot of the "mush" on worn records. Second, the output is always going to be low -especially with other than original Pickering-Seeburg styli. So, at this point you have the typical problem with these old machines. Option one: get either a redhead or blackhead cart. Option two: get a 345-03D retro cart. This will require either adding weight or cutting down the counterweights to balance it. The sound quality will be the best possible (i've used these connercially for 26 years) but it will still be somewhat lower in level unless the preamp is modified and the the original styli are no longer being made. Option three: replace the existing tonearm with the later stereo arm. We can go into that if you are interested. there is a fair amount of work involved. None of these are cheap, simplest is option one. Otherwise, leave as is. Hopefully the arm is balanced and not chewing up the records. RobNYCThat's kinda what I was figuring my options were, investing in a new cartridge assembly; which doesn't appear to be cheap by any means. If I want the box to sound better though I really don't have much choice. If I get a black or redhead, is there a way to check them and make sure they're in good working order? I found a red head on ebay measured out at 1.7k ohm, not sure if that's a good number or not. Of course if I went with the 345-03d I have the option to purchase that new, which I think I've seen them about $300. When purchasing these cartridges, is there info on adjusting the counterbalance to accommodate it? Replacing the tonearm with a stero one doesn't interest me, wanna keep the box as intended and mono. I'll have to thumb through my service manual and see if there's checks or adjustments for the tonearm; just to verify it's properly balanced and not ruining any records. |
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Post by robnyc on May 22, 2018 12:41:32 GMT
A redhead anywhere in the range of 1.5-2.00 should be OK. To balance the 345-03D the counterweights must be cut down: www.flickr.com/photos/90641375@N06/35677983773/www.flickr.com/photos/90641375@N06/36440438336/ Ron and others have said that they can just glue extra weight to the top of the cart to balance it. Again, the output of that newer cart is lower and there is no guarantee of quality replacement styli though there are ways of adapting other styli to fit. If you are only going to use older and mostly mono records and not too critical about quality, the redhead is "ok". I suggest getting several spare styli since they are only being made by one source. The same people are making a stereo compatible stylus but as in the past, these have lower output. RobNYC |
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Post by Ron Rich on May 22, 2018 13:40:28 GMT
Rob,
The "output" of the currently made "compatible" stylus, for the "red head"cart. and "Twin Stereo", cart. is very close to that of the OEM Pickerings--BUT they both are extremely critical about needle pressure--it MUST b 4 grams ! Yes--I cut down a lead fishing weight, or car wheel balance weight, to add to the top of the 345's (too lazy to dis-assemble the tone arm cradle !!) Ron Rich
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Post by vipertblck on May 22, 2018 17:18:40 GMT
A redhead anywhere in the range of 1.5-2.00 should be OK. To balance the 345-03D the counterweights must be cut down: www.flickr.com/photos/90641375@N06/35677983773/www.flickr.com/photos/90641375@N06/36440438336/ Ron and others have said that they can just glue extra weight to the top of the cart to balance it. Again, the output of that newer cart is lower and there is no guarantee of quality replacement styli though there are ways of adapting other styli to fit. If you are only going to use older and mostly mono records and not too critical about quality, the redhead is "ok". I suggest getting several spare styli since they are only being made by one source. The same people are making a stereo compatible stylus but as in the past, these have lower output. RobNYC Sounds like i'd be better off with a black or red head, easiest thing to put in without messing with weights or what not. Plus if the output of the 345's isn't as good as an old black or red head..that would prolly end up bothering me too. You mentioned getting spare styli for the cartridge I end up finding, is that just the needles? Styli/ needle, same thing? Also as far as the needle pressure and balanceing tone arm, thing I found that in the adjustments section of my service manual; looked pretty straight forward except the needle pressure; i'll need to find a gram gauge for that. |
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