gary_wong5
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Posts posted by gary_wong5
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It seems that you have second generation of 98LS speakers.
Later improved 98LSI models didn't have those plastic rings around woofers and lower mids.
They were improved by adding some resistors in front of lower and upper midrange, which made them smoother sounding.
Also, one of the capacitors was removed in front of the tweeter and its phase was inverted too.
Earlier LS version was known for producing listeners fatigue.
While I was refreshing my crossovers with new capacitors, I also upgraded them to LSI versions.
Here you can see the restoration I did on my pair:
http://www.kujucev.com/ar98ls/ar98.htm
Here is the modded LSI version of the crossover:
Mr Kuja, hope that you are still enjoying yours. Recently has some free time to try out the LSi version modification. Could you please be more specific what resisitors you have added, and which capacitor has been removed? And I hope my dear members here give more advice on this, if any.
Best regards.
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Hi Pete,
I have tried out 4, 5 and 6 dB of 4.7K version and finally settled at 5 dB and 6 dB. I also tried switchable 5dB and 6dB set with reference to your DPDT switch. When switched to center off, there is obviously some signal loss but is not an issue to me as I prefer 6 dB of boost.
I am using a 40 watt HAKKO Red No. 502 for soldering work, as this http://us.100y.com.tw/ChanPin.asp?MNo=9882 Really went through a hard time to materialize this BSR set for a chemist
I've been asked for a schematic for the version with the 3 way switch, for 4, 5, or 6 dB of boost.I actually just built it, didn't draw a schematic, I probably hand drew a sketch for layout
purposes but honestly my hand drawings are not that clear so I'm not sure if I saved it, LOL.
The switch is a DPDT center off 3 pos switch, that is available from RS.
I found a simpler way to do the switching that allows a single DPDT, center off, 3 pos switch to be used:
Build it for 4 dB of BSC, which has a shunt R of 7.5K, C of .047 uF
Wire the center of the DPDT switch to the output terminal, one section to the Right, other to the Left.
One switch side gets 22K in series with .01 uF to ground, one for R another for L, this is +5 dB,
Other switch side gets 10 K and .022 uF to ground, one for R another for L, this is +6 dB,
Center off pos is +4 dB.
HF boost just switches in the .0047 uF cap.
Does this make sense?
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Hi Pete,
I have put all the components together follow exactly your recommendation. It is my first experience to having such kind of project, boght soldering gun, soldering paste, etc. Hope my skill is not laughable.
I connected the BSR to my integrated amp Technics SU-A900MK2 tape loop. Wow, very sweet and warm midrange and the bass extention is geat. No more ears piercing high and I could listen to my Advent/1 for long time.
Thank you Pete.
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Hi Pete B,
I have bought C1 and C2. However the shopkeeper told me that for the R1 and R2, she got to know whether they are 10W, 5W, 2W, 1W, 1/2W, 1/4W5% or 1/4W1%. Please advise me which one should I buy
And is the green line in the photo a ground cable? Many thanks!
Your recommended info:-
Yes it is the 6 dB version from post #41 in this thread:
4.7K Version, these values are for RL = 47K or typically an EPL or tape monitor
loop:
R1 = 4.7 K, C1 = .0047 uF
6db: C2 = .068 uF R2 = 4.3K
C1 can be two .01 uF green mylar caps from Radio Shack in series.
C2 can be a .047 uF and .022 uF also from Radio Shack in parallel.
Just so happens that I have a good supply of .068 uF, .01 uF, and 4.3K resistors
here. I forgot to include them in my rush to send it to you. I'll get them off
to you soon. Figured I'd wait to see how you liked it.
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Dear Pete B,
My Advent/1 high is a bit harsh. Can I apply the mod option for reducing the high?
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Hi Kuja,
I am keen to upgrade my 98LS's cross-over to Improved version. But I am not expert in electronics. I shall show your schematic LSi to my technician and request him to carry out modification. May I confirm this is the correct LSi cross-over?
Kind regards,
Gary
It seems that you have second generation of 98LS speakers.Later improved 98LSI models didn't have those plastic rings around woofers and lower mids.
They were improved by adding some resistors in front of lower and upper midrange, which made them smoother sounding.
Also, one of the capacitors was removed in front of the tweeter and its phase was inverted too.
Earlier LS version was known for producing listeners fatigue.
While I was refreshing my crossovers with new capacitors, I also upgraded them to LSI versions.
Here you can see the restoration I did on my pair:
http://www.kujucev.com/ar98ls/ar98.htm
Here is the modded LSI version of the crossover:
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I need your constructive advice now!
Is it worth to exchange my 98ls' with 9ls' with a top up of US$406 !??
Gary
Hi Minh Luong,Frankly speaking I have no expertise in electronics. But I do guess that those Culver are replacement caps in view of the colour variant. Can anyone else help to verify this?
Yes! I have remove the yellow sponge after conducting some trial and error whereby they sound most airy and transparent. There is no sounding problem so far. Actually they sound very much better than my PSB Image 4T.
Best regards,
Gary
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Gary
On the crossover shown, the two deep blue Culver caps seems like were replacement of the original? If both of your AR98LS don't have obvious sounding problem, I would suggest don't do anything with the caps change yet unless you are very handy and had done many soldering on small electronics parts before. Cold solder is the worst case on cap change! Beside you have very limited space to squeeze in the much bigger polypropylene capacitors with the same uF value even for the smaller 250VDC rated one. I would remove the yellow sponge shown on the speaker grills since it hurts the dispersion of the tweeter and midrange more than tighten up the focus as you may think!
Minh Luong
Hi Minh Luong,
Frankly speaking I have no expertise in electronics. But I do guess that those Culver are replacement caps in view of the colour variant. Can anyone else help to verify this?
Yes! I have remove the yellow sponge after conducting some trial and error whereby they sound most airy and transparent. There is no sounding problem so far. Actually they sound very much better than my PSB Image 4T.
Best regards,
Gary
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Yesterday, I was free to open up my 98ls' and would like to know:
1) Refer to my attached photo, is the x-over is of original and never recap before?
2.) Some double-sided adhesive tape residue on the plastic grille, so I wonder if there is some plastic foam attached (original specification). I have tried putting some foam around the grill which I could hear more refined mid and bass.
Please advise.
Regards,
Gary
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Hi GaryI am from South Vietnam. The AR-303 review article you mention from Sonic Review from Hong Kong was written by my friend Top Class Tom. I was the one who pushed him hard to review the AR-303 speakers so he end up had to bought a pre-owned pair to write that report to calm me down. If you still have the magazine, you will find my name was mention in the beginning of the review. One mistake in the article that the Writer and Editor never corrected as I had told them was all three drivers used in the AR-303 were no longer the same as the original AR-3a drivers. They may look similar but with different specification.
The easiest way to distinguish the early LS series from the LSi series is the LSi series speakers got rid of the plastic mid bass and woofer driver guards which are more for cosmetic and not for functionality therefore the front baffle of the LSi series speakers were routed through the walnut veneer and MDF to sit all the drivers flush to the surface with updated crossover.
Attached is picture of AR9LSi to see flush mounted drivers.
Minh Luong
Hi Minh Luong,
Thank you for your explanation for LS and LSi.
Yes! I saw your name in Sonic Review. I consider myself lucky as still keeping those old magazines. I started hi-fi system in 1993 and only has the chance to listen to and own my Classic 8s' last Spetember. I "addicted to" AR's sound since then, and have had let go my psb and Infinity. Now I have AR98LS, Classic 8 and M-.5 (unidentified species?!) There is AR9LS around me and could be my next target. Please suggest me any other models that are worth collecting. Thanks!
Gary
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Hi Gary
Are you from Hong Kong? I am just guessing because in Hong Kong people are very favorable to rosewood furniture therefore they have the tendency to tint any kind of wood to reddish tint just like your AR-98LSi speakers is showing. The original AR-LSi series speakers are more of the yellowish brown walnut veneer as shown in the color brochure.
One thing I would suggest you to do is to unscrew the driver screw one at a time and get rid of the rust with very fine grain cloth base sand paper and lubricate them up with WD40 to stop them from rusting further.
Minh Luong
Hi Minh Luong,
I am from Malaysia. Are you from Hong Kong?
I got my pair from Singapore after long searching out. In fact I have doubt too about the reddish tint (slight) and keep on asking myself why they look different from AR LS brochure. What a pity they are not of original condition... But I really love their performance. How to tell if they are LSi version? The seller said he bought them 7 years ago as used pair from somebody. Probably the first owner is Hongkee or he had ever worked in Hong Kong.
As I shall keep these LSs' for like, I thank you for your kind advice on rusty screw.
Gary
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Thank you for all the advice. Since there is no abnormal sound out from the mid, I shall leave the dent as it is.
What is the suitable speaker stand's height for these AR98ls? Kuja, may I know the one shown in your picture?
Thanks!
BR
Gary
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Dear All,
I bought a pair of AR98ls yesterday. They are really sound great! But I am now confused why my AR98ls' look differrent from the one shown in AR Library:
http://www.classicspeakerpages.net/library...series_brochur/
whereby the front face is black colour.
Is that my ARs' have already modified by the previous owner(s)?
What is the function of the small knob situated above the speaker socket (please see the attached picture)? Can anyone suggest me how to restore the dented midrange driver?
Please help!
Regards,
Gary
AR98ls
in Acoustic Research
Posted
I converted my AR98LS to "i" version last night. As 2.5ohm is not readily available in Malaysia, I tried 2.2ohm instead as the shopkeeper explained that the difference is only 0.1% whereby our ear cannot hear and differentiate. Is that true? Is 2.5ohm better? No recap is done. Just added in those resistors. The mid and high are now very sweet, smooth and listenable.
What I am still wondering is that the the phases of the tweeter are originally inverted: Blue (-), Yellow (+) (different from the LSi X-over). Should I restore the phase? What will happen to tweeter if re-phase?