Goldwood GT-25 3.5" Paper Cone Tweeter
https://www.madisound.com/store/product_info.php?cPath=45_229_324&products_id=8595
https://www.madisound.com/store/product_info.php?cPath=45_229_324&products_id=8595
Is this a drop-in tweeter replacement for Altec 893a?
- Thread starter Pianist
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The original 893a tweeter is 30685. The impedance, as I measured, is 5.8ohm. This Gt-25 tweeter is physical similar/identical and is said to be 8 ohm. Will that be a problem?
Dan ʕ•ᴥ•ʔ
Peanut Head
You may have to change cap value to get the crossing frequency to jive with the different impedance.
Remember you are measuring DCR with a meter, not impedance. A DCR measurement will be less than that of impedance.
There are these as well... http://www.parts-express.com/wizards/searchResults.cfm?srchExt=CAT&srchCat=453
Remember you are measuring DCR with a meter, not impedance. A DCR measurement will be less than that of impedance.
There are these as well... http://www.parts-express.com/wizards/searchResults.cfm?srchExt=CAT&srchCat=453
What does DCR mean?
The link you provided couldn't direct me to the webpage. What's the model number of the tweeter on P-E you were referring to?
Many thanks!
bowtie427ss
Lunatic Member
DCR = Direct Current Resistance.
Link works for me, it's actually to a page with several tweeters on it, IMO the best choice is the phenolic ring tweeter. It's probably a slight improvement over the stock Corona tweeter.
FWIW, the 30685 is generally a CTS product, but i also have some 30685's that were made by Becker, and they're a bit different than the CTS versions. The phenolic ring tweeter is a very suitable replacement.
Link works for me, it's actually to a page with several tweeters on it, IMO the best choice is the phenolic ring tweeter. It's probably a slight improvement over the stock Corona tweeter.
FWIW, the 30685 is generally a CTS product, but i also have some 30685's that were made by Becker, and they're a bit different than the CTS versions. The phenolic ring tweeter is a very suitable replacement.
Thanks.
To replace 30685 with minimum alteration to the crossover, should I choose 8-ohm tweeters?
bowtie427ss
Lunatic Member
Yes, 8 ohms.
I see you have another thread seeking a schematic for the network. Do you have a wiring problem?
I don't have a schematic, but i do have an un-altered pair of working Corona's in my workshop and may be able answer questions or provide you with a pic of a network if the need arises. Just let me know as it might take a day or two to get one down and get into it.
I see you have another thread seeking a schematic for the network. Do you have a wiring problem?
I don't have a schematic, but i do have an un-altered pair of working Corona's in my workshop and may be able answer questions or provide you with a pic of a network if the need arises. Just let me know as it might take a day or two to get one down and get into it.
I don't know tech that much. I am trying to find out the layout of the crossover. In particular, how the HF switch is connected. I am currently putting the switch in the +3db position, and I would like know how the signal is routed in that position. So far, I only know that there are 2 5uf capacitors (which I will replace).
Thanks!
Dan ʕ•ᴥ•ʔ
Peanut Head
This was the one I thought would make a better substitute. http://www.parts-express.com/pe/showdetl.cfm?Partnumber=270-252
Would its 2,000-15,000 Hz frequency range, vs Goldwood's 1500-21000 (https://www.madisound.com/store/product_info.php?products_id=8595), be somewhat limiting? Should I really trust Goldwood's rating, given that it's a paper cone?
bowtie427ss
Lunatic Member
My advice would be to trust the decision by so many manufacturers to use phenolic ring tweets as an original component in so many well regarded speaker designs, and to trust the demand by consumers that has brought the phenolic ring tweeter back into production and availability.
That said, the Goldwood just "looks" cheesy to me. In all fairness i have used a couple of Goldwood drivers in the past and my opinion was that they're good, better than their price might suggest.
But, in this case i'd go with the proven example. i've never heard those phenolic rings sound "bad" in a circumstance where i could blame it on the tweeter itself. In fact, i've mostly found the speakers that used them to be good sounding and well established among their peers.
Dan ʕ•ᴥ•ʔ
Peanut Head
We first need to find out what frequency it's crossed at and whether it's first order or second order. To do that, we need a clear drawing or schematic of the crossover showing the capacitor values (uF) and inductor (mH). If they only used a cap to the tweeter, it's first order. If a cap and coil was used together, it'll be second-order. Take a clear close up picture if you can.
(The crossing frequency needs to be known so a tweeter isn't used that will be crossed lower than it can safely play without damage.)
I can't speak for the Goldwood, but my guess is the response they listed is down by several dB at 21kHz.
(The crossing frequency needs to be known so a tweeter isn't used that will be crossed lower than it can safely play without damage.)
I can't speak for the Goldwood, but my guess is the response they listed is down by several dB at 21kHz.
geiman
E Wave appellation #49
The CTS phonelic ring tweeters are used in some models of Altec speakers.
I have a pair of Model 5 that uses them. I replaced two of them that had failed with the ones from Parts Express. I could tell no difference between the originals and the ones from Parts Express. They were identical in every way including how they sound.
I have a pair of Model 5 that uses them. I replaced two of them that had failed with the ones from Parts Express. I could tell no difference between the originals and the ones from Parts Express. They were identical in every way including how they sound.
I don't have a camera right now. But here is some relevant info (see the pictures): http://www.audiokarma.org/forums/showthread.php?t=254799
According the brochure, the crossover is at 2500hz. http://www.lansingheritage.org/images/altec/catalogs/1971-home/page23.jpg
Good info!
Right. Since I am going to order caps from Madisound in the next week or so, I will just get a couple of them to try out. I will report back soon.
Installed those Goldwood GT-25 paper tweeters in my Altec 893a and having been testing/listening to them for a few days. Physically they are drop-in replacements for the old ones. Sound-wise, they are extremely similar to the old ones, but are slightly clearer and offer perhaps 5% more HF extension. With the Goldwoods, my beloved Altecs gain some needed definition while still retain its overall warmth. Needless to say, I am very happy and really surprised that modern (and really cheap) replacements can be this satisfactory. Will post a pic once I am done with my work.
