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It is currently Sun Dec 21, 2014 11:34 am

Platinum Amazings Lost Bass!

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talmadge3

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Post Sun Feb 16, 2014 11:58 am

Re: Platinum Amazings Lost Bass!

subs and amp
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radioeng2

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Post Sun Feb 16, 2014 12:15 pm

Re: Platinum Amazings Lost Bass!

At one of the fests, we set a pair of the Cinama Ribbons up on a stool in front of a pair of ALIII's. It was amazing how good that small ribbon did in comparison to the big ribbon! Probably some differences, but on a quick listen back and forth, it was surely cool how good the ribbons did do.

Of course,they were made with the idea of a sub adding in the bottom end. As you're suggesting here. And the CR isn't going full range with the sound like the big ribbon is. So there is some things that long term listening between them would reveal.

The character of the OB bass would certainly be different from those woofs. Sealed bass systems though have some of the same style of quick bass. They might go lower, though I don't know anything about them. Sealed is about the sound though, more than ultimate extension on the bottom end. I'm a huge believer of the OB bass and I'd probably be going that direction for me.

I understand your frustration after having them around, spending money and not getting there. I think you should fix them and enjoy the rewards of the big speakers for the long term. But I could understand going another way too.

Mark
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Robert R

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Post Sun Feb 16, 2014 1:12 pm

Re: Platinum Amazings Lost Bass!

Yeah, Mark - that was Carverfest #2, in Cabin 11. Bob's first Fest appearance. The little CRM-2s stood up well next to the Rabbit's IIIs. Three reservations I have:

1. Possibly we can't help making allowances for the small size, and it affects our judgement a bit. Ideally all the speakers would be behind a curtain or something, or we'd wear blindfolds, to make it really fair. The most heard comment was along the lines of 'wow, they are unbelievable for their size' [my emphasis]. And indeed they are. Bob's genius and perseverance at it's best - they sound very big.

2. When we really cranked them up, the little guys crapped out before the big ones.
Dave Sauter and I did that experiment when the rest were all at dinner. Program was big orchestra and chorus (Orff's Carmina Burana). But that's a very big room, and a difficult one acoustically - all that glass and bare wood.

3. In the octave between 100 and 200 Hz there is a bit of a problem, especially at at high levels. The true sub contributes very little above about 100 Hz, it's highest crossover setting, and it's really better at what it's designed for if it's set a lot lower. And the CRMs are really laboring below 200 Hz. So you really need a "mid-woofer" (Hsu sells exactly that, for its satellite systems). It gets a lot trickier to set up when you go to a three-way, tri-amped systems, but once you get it right, the extra punch is well worth it.

RobertR
"You know what folks? I'm happy."
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Robert R

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Post Sun Feb 16, 2014 1:20 pm

Re: Platinum Amazings Lost Bass!

talmadge - I should add as a sort of PS that in the same cabin I just wrote about there was a pair of Platinums [Skip's], on the other side of the room. For my money, they were the best, most musical things in the place.
RR
"You know what folks? I'm happy."
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Toy Maker

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Post Sun Feb 16, 2014 1:21 pm

Re: Platinum Amazings Lost Bass!

Check the white resistors on the crossover. I had to fix a guys a while back. $.75 fix ;)
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Robert R

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Post Sun Feb 16, 2014 2:15 pm

Re: Platinum Amazings Lost Bass!

Talmadge - My post on the woofer crossovers was dead wrong. No way to edit it or remove, it seems. The words choke and capacitor got reversed, as they would be in a high-pass filter, such as for the ribbons.I got things confused, not the first time lately. DO NOT SHORT/JUMPER THE BIG CAPACiTOR (C-1) - it's the Coil, L-1 that is in series. The cap is about 450 mf, non-polar, 150 volts. With it completely removed (or open) you should still have woofer action, though with an excess of highs reaching the woofers. It's the choke coil that is in series. That coil, on the red wire's route to the woofer bank, should read maybe half an ohm on a meter. If that opens, no woofer action at all. But they seldom fail.

This problem is a bit of a puzzle, in that both channels quit some months apart. If your speakers were subjected to a terrible injection of nasty hum and noise, you could fry all four woofer voice coils in one channel in a second, even before the fuse blew, and they would still look OK but not work right, if at all. But then that would have had to happen again those months later to kill the other side. The test for this is you manually move the cones straight in and out, to see if there is mechanical resistance/rubbing that impedes the excursion, which is as much as one inch in either direction in those woofers. Healthy ones rub a bit if you don't move them perfectly straight.

Did you test the big Q-control pots? If they open, no bass either.
"You know what folks? I'm happy."
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wrstps

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Post Sun Feb 16, 2014 4:12 pm

Re: Platinum Amazings Lost Bass!

OK let’s start from the beginning and I don’t mean to sound condescending by any means, I just don’t know your skill set. The first thing I would do is start with the amp and pre. If you have another set of speakers and you know them well, hook them up and see if they sound the same as you remember and the bass is there. Next, if all seems alright then pull the fronts and backs off the silvers. I have seen several of these with short leads to the ribbons and with the age of the wires they have become brittle and the way the wires are held in place you could have dislodged or broken a solder joint to any of the woofers, even if you move them occasionally this could happen at any time with the age of these. The back and forth movement of the wires has been a problem with a these due to age and if one woofer has a bad connection you now have a 12 ohm speaker and most amps don’t like this at all. In fact the bass is the first thing to go at this resistance. The other issue is: if you are like me and drink heavily and you ears become unaware of the neighbors (play it loud) you may have a shorted voice coil, the woofers in the silvers can take a lot but there is a point of no return or what I call the “O SHIT” WTF did I do! If you were listening to music and you were standing in front of the silvers and you thought something slapped you in the face and you didn’t know where it came from this could be the problem. Take a little time and gently push the cones in and see if you feel any binding or grinding. If you have gotten to this point the next step is to unsolder the center woofer and connect directly to the speaker leads plus and minus it doesn’t matter and unhook the other speaker before doing this if this works and the bass comes back short the onboard tone controls out of the picture, if you need help let me know. If all of this fails you most likely have a set of bad crossovers. Let me know the outcome
Ray in Michigan
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Robert R

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Post Sun Feb 16, 2014 5:57 pm

Re: Platinum Amazings Lost Bass!

WRSTPS - Silvers have three parallel-connected 16 ohm woofers, resulting in 5.33 ohms for the trio. Platinums, which are his model, have four of the same, resulting in a 4 ohm quartet. Both of these measurements are resistance only; there's the reactance of the voice coils and the crossover to consider as well, not to mention the Q control resistor, which varies from zero to eight ohms in series. Actual impedance will depend on frequency, of course; in these speakers it lowers as frequency lowers, IIRC.
So anyway, if one woofer in a Plat opens up, as far as bass is concerned you now have essentially the same load and the same performance as a Silver.

The ribbons are around 4 ohms, resistive, and they have a more complex crossover involved, all of which runs in parallel with the woofer side. I don't know where you are getting 12 ohms from, but I can assure you that a 12 ohm load would not damage any amplifier I ever saw, though the output wattage rating would somewhat be reduced, of course, unless you're running it from an output transformer with a 12 ohm tap, something I've never seen. A tube amp can be damaged by running hard into no load, but even it you ripped out all 4 woofers, the ribbon still provides a substantial load here.

If you read the last part of the post right above yours you will see that he has already been told how to check for rubbing voice coils. And if you read his very first post you will see that he has already tried different electronics.
"You know what folks? I'm happy."
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wrstps

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Post Sun Feb 16, 2014 6:05 pm

Re: Platinum Amazings Lost Bass!

I agree, howerver if one wire comes loose from any speaker in the loop things change and I have seen this happen kinda been there and done that. Good to hear from ya.!
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Robert R

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Post Sun Feb 16, 2014 6:16 pm

Re: Platinum Amazings Lost Bass!

Umm, no, not really. It's not a loop - maybe your are thinking of Original Amazings. They were quite different - low impedance woofers wired in series, which is a loop, I guess. These are in parallel, sometimes casually referred to as a "bank".
But even if you cut them all out of there your amp is in no danger, unless somehow some loose wires get touching and manage to short the speaker output.

RobertR
"You know what folks? I'm happy."
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wrstps

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Post Sun Feb 16, 2014 6:40 pm

Re: Platinum Amazings Lost Bass!

I agree with everything you said. however if any of the two lower woofers becomes disconnected for what ever reason the impeadence changes, they still work but the bass is reduced. I have had this happen. My amps still functioned I just had to produce more voltage to aquire the same levels that I had before the disconnect. I had 3.776 at the ribbon and 7.004 at the woofers. after the reconnect I had 3.997 at the woofers. and everything was good.
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Robert R

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Post Sun Feb 16, 2014 7:15 pm

Re: Platinum Amazings Lost Bass!

Now I get what you mean. Sure, if you have fewer woofers functioning you will hear less bass. They are there in numbers because just one wouldn't do the job, not in that design.
RR
"You know what folks? I'm happy."
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talmadge3

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Post Sun Feb 16, 2014 7:24 pm

Re: Platinum Amazings Lost Bass!

I emailed Rolland about rebuilding my crossovers. Of course he said no problem just send them out. My fear is after rebuilding the crossovers and having already replaced the woofers plus having the ribbons rebuilt that the problem may somehow still exist, however irrational that is! ](*,) If you read through all the posts you will see that I have changed amps, (silver 7t's and sunfire) preamps,(sunfire and Lexicon MC-8) wires and moved the ribbons from speaker to speaker. It has to be a crossover problem, right? :-k I will try and post pictures of the crossovers tomorrow. Just looking at them I see nothing suspicious. Also remember these speakers once produced tremendous bass. For the record I have not overdriven them. All of the woofers are working they simply aren't producing the bass that they were previously, a lot less bass.
This is like having a boat, I think Ive stepped in a money pit. However I love these speakers when they are working properly!
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Robert R

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Post Sun Feb 16, 2014 8:03 pm

Re: Platinum Amazings Lost Bass!

I'm hoping you can be sure they need to be sent before you send them. Did you try the trick of working the bass controls in back?
RR
"You know what folks? I'm happy."
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Robert R

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Post Sun Feb 16, 2014 8:13 pm

Re: Platinum Amazings Lost Bass!

Next trick was to bypass the whole control, to be sure they aren't both burned out.
Last edited by Robert R on Sun Feb 16, 2014 8:14 pm, edited 1 time in total.
"You know what folks? I'm happy."
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