RTA 12B different caps
geppy1
Posts: 3,075
I have two pairs of RTA 12Bs One is from 81 with the brown top crossover and black caps on the main board and came with Peerless. The other is from 84 and has the green board with blue cap and the main board and has blue caps. It came with silver faced SL1000 but I have seen pther untouched ones come with Peerless. 1983-84 seems to be a transition era. Using the same tweeter on both they sound different. The caps on the crossovers are the reason. Even though the blue and black caps have the same specs they are different sizes and sound different. Does anyone know anything about these different caps? I like the sound of the earlier croosover. The later one seems more laid back and last time I was at a club or concert music is anything but laid back.
I know someone is going to suggest RDO194 as it seems to be the automatic thing to do. I have them here and have compared them extensivly and myself and others feel they have a very nice sound but it stops at the top of the speaker. The Peerless and tghe SL1000 seem to extend much higher above it.
I know someone is going to suggest RDO194 as it seems to be the automatic thing to do. I have them here and have compared them extensivly and myself and others feel they have a very nice sound but it stops at the top of the speaker. The Peerless and tghe SL1000 seem to extend much higher above it.
Post edited by geppy1 on
Comments
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I have two pairs of RTA 12Bs One is from 81 with the brown top crossover and black caps on the main board and came with Peerless. The other is from 84 and has the green board with blue cap and the main board and has blue caps. It came with silver faced SL1000 but I have seen pther untouched ones come with Peerless. 1983-84 seems to be a transition era. Using the same tweeter on both they sound different. The caps on the crossovers are the reason. Even though the blue and black caps have the same specs they are different sizes and sound different. Does anyone know anything about these different caps? I like the sound of the earlier croosover. The later one seems more laid back and last time I was at a club or concert music is anything but laid back.
I know someone is going to suggest RDO194 as it seems to be the automatic thing to do. I have them here and have compared them extensivly and myself and others feel they have a very nice sound but it stops at the top of the speaker. The Peerless and tghe SL1000 seem to extend much higher above it.
As caps lose capacitance, they shift the crossover point upwards.
This means the tweeter handles LESS of the highs, and gives a closed in sound.
Different caps lose capacitance differently.
1981 is almost 27 years ago, it is a good bet your caps have changed value.
Easy enough to correct by simple replacement.
I suggest the British Clarity Caps from Madisound.
They are reasonable, and I feel they a bit sound better then Solens.
Even the Bennic Poly Caps are decent, and a BIG upgrade over what you now have. -
Thanks for the reply. I am still wondering what is the difference between the black and red ones and the smaller blue ones?
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May just be from different manufacturers ?Thanks for the reply. I am still wondering what is the difference between the black and red ones and the smaller blue ones?
They are STILL old caps, regardless if they are Mylar or Electrolytics.
Old caps DO go bad, even sitting on the shelf.
One friend of mine replaced all the caps in his pre amp with NOS Vintage caps.
The preamp hummed like crazy.
NON vintage caps are still old caps, LOL
Age is age, just as in an automobile, even one with low miles.
I would replace ALL of them, but TRY and save the old ones, in case you do not like the new sound ?
IME, the tweeter high pass cap is THE most important one, but I would replace all of them, and the resistor too.
There aren't a whole lot of them.
