AR LST and Audio Research drivers

[Wally]

I bought a set of AR LST's recently. S/N 779 and 787.

These are the original LST's that use the 12" woofers. Someone at some point substituted 10"woofers with a masonite adapter ring to make them fit the 12" hole.

These woofers are clearly marked Audio Research and I do know that is not Acoustic Research.

First, does anyone have a good set of 12" AR3/LST woofers that they are willing to sell?

Second, has anyone modded the crossover, eg, eliminated the autotransformer and switch. What other elements need to be added to the crossover eg resistors to produce a 'flat' response. One of the switches is gone in one unit and I have wired directly to the autotransformer. Woofer at 0, MR -3 , TW 0 for now.

Has anyone bypassed the transformer and wired direct? Did you use resistors, pots or L-pads to flatten the response?

The sound right now is bass shy, probably because the new woofer is not a good match. Otherwise the mids and highs sound great, just missing a bit of bass. I could wire the mids and tweeters to a lower tap... I'm still experimenting.

My old set of AR4X has more bass.....

regards, Wally

[Pete B]

Hi Wally,

You probably read the threads concerning the AR 11/12" woofer and should probably look on ebay for the correct woofers rather than using Tonegens if no one responds here.

Are you located in the North East by any chance? I'm fairly backlogged with speaker projects but would be interested in working out the auto-transformer bypass and A/Bing the result if your interested.

Regards,

Pete B.

[Wally]

Hi Pete,

I'm located near Toronto in Canada.

I'd appreciate any input I can get regarding upgrading/modifying the crossover network and the autotransformer. I've had no replies yet regarding original replacements. One fellow has tonegens and he gave me the name of someone who modifies them by changing the spider etc. to make them more like the original. I think I'll try the tonegens as is for now and try to compensate for the efficiency with the auto transformer. If I can eventually find a beat up pair of AR3's with good woofers then I can swap out the woofers.

Thoughts..

regards, Wally

>You probably read the threads concerning the AR 11/12" woofer

>and should probably look on ebay for the correct woofers

>rather than using Tonegens if no one responds here.

>

>Are you located in the North East by any chance? I'm fairly

>backlogged with speaker projects but would be interested in

>working out the auto-transformer bypass and A/Bing the result

>if your interested.

>

>Regards,

>Pete B.

[soundminded]

Is this a Tonegen version of the original AR 12" woofer. The 1259 will not work. It requires twice an enclosure twice the volume.

[rjr513]

Looking for woofers try this http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...ssPageName=WDVW

Hope this helps, Troubleshooter

[RoyC]

Not the 1259...Pete is referring to the AR replacement manufactured by Tonegen when AR stopped manufacturing them in the USA. There have been several discussions in recent threads regarding the evolution of the AR 12 inch woofer and problems with the Tonegen version as a "drop in" replacement for older AR models.

Roy

[RoyC]

Those woofers are the early 70's version with the large masonite ring and long leads on the cone. That version wasn't changed much until the mid to later 70's and would probably work very well in the LST's.

Roy

[Wally]

Thanks Troubleshooter, I put in a bid.

regards, Wally

[Rlowe]

Roy,

You refer to the masonite ring on the woofer.

Do you know what purpose it serves.

You imply it was was removed at a later date.

Richard

[RoyC]

Hi Richard,

The masonite is what the foam surround attaches to. It is simply wider and visible on the earlier woofers than on later versions. More importantly, the later versions had "stiffer" spiders and stronger magnets making them less desirable as replacements in earlier models. The Tonegen product was based on the later versions.

Roy

[Pete B]

Hi Wally,

Toronto, that's far. Looks like you found some nice stock woofers on ebay. It'd be difficult to suggest changes without having a pair of LSTs to measure and to use for testing mods. What sort of test equipment do you have? DVM? Capacitance or inductance meters?

I took another look at the LST crossover schematic and noticed that when the woofer is at the highest tap the autotransformer is across the woofer where it simply acts as an inductor or a highpass filter in combination with the large input cap. This behaves as a subsonic filter and might help to reduce woofer bottoming from very low frequency energy. This would be like a subsonic filter but I'd need the autotransformer winding inductance to calculate the cutoff frequency. It could be an advantage with subsonic noise from LP for example, however the autotransformer still can distort/saturate even in this function and a line level subsonic filter is the best solution.

Regards, Pete B.

>Hi Pete,

>

>I'm located near Toronto in Canada.

>

>I'd appreciate any input I can get regarding

>upgrading/modifying the crossover network and the

>autotransformer. I've had no replies yet regarding original

>replacements. One fellow has tonegens and he gave me the name

>of someone who modifies them by changing the spider etc. to

>make them more like the original. I think I'll try the

>tonegens as is for now and try to compensate for the

>efficiency with the auto transformer. If I can eventually find

>a beat up pair of AR3's with good woofers then I can swap out

>the woofers.

>

>Thoughts..

>

>regards, Wally

[Wally]

Hi Pete,

I have all the necessary gear. DVM, scope, audio gen, freq counter, LCR meter etc.

Interesting about the filter idea. There is also a huge cap in series with the inductor about 5000 ufd if I remember.

Saturation is not an issue right now cuz I don't have the right woofers. Notice in the schematic that the tweeters are just on a cap.. 6db/oct. In the AR3A I believe it was a 12 db network. Wonder if that would be beneficial from the point of protecting the tweeters...

The midrange is more than 6db network but not a full 12... not sure if it's the same as the AR3a.

If I was to eliminate the autotransformer would I have to put in some series resistance in the tweeter and the midrange lines to reduce efficiency? eg when you multiple woofers you get a 3db increase in bass frequencies for every doubling of drivers.. assuming impedance stays the same... does the same hold true for tweets and mids?

regards, Wally

>Hi Wally,

>

>Toronto, that's far. Looks like you found some nice stock

>woofers on ebay. It'd be difficult to suggest changes without

>having a pair of LSTs to measure and to use for testing mods.

>What sort of test equipment do you have? DVM? Capacitance or

>inductance meters?

>

>I took another look at the LST crossover schematic and noticed

>that when the woofer is at the highest tap the autotransformer

>is across the woofer where it simply acts as an inductor or a

>highpass filter in combination with the large input cap. This

>behaves as a subsonic filter and might help to reduce woofer

>bottoming from very low frequency energy. This would be like

>a subsonic filter but I'd need the autotransformer winding

>inductance to calculate the cutoff frequency. It could be an

>advantage with subsonic noise from LP for example, however the

>autotransformer still can distort/saturate even in this

>function and a line level subsonic filter is the best

>solution.

[Pete B]

>I have all the necessary gear. DVM, scope, audio gen, freq

>counter, LCR meter etc.

This is excellent, so you can take some measurements.

I've started to think that serious restorers should make a spread sheet with a line for every part in the speaker, then measure DCR, inductance, capacitance, resistance, free air resonance, part number etc. where applicable for drivers and crossover components. LST's will offer a lot of data for the mids and tweeters with 8 used in a pair, average value and percent deviation for groups of common parts could easily be calculated. It's a lot of work but would help nail down exactly what we're dealing with.

>Interesting about the filter idea. There is also a huge cap in

>series with the inductor about 5000 ufd if I remember.

Yes that's the large cap that I mentioned. If you happen to disassemble the speaker it would help if you could measure the DC resistance and inductance from each tap on the auto-transformer to the common. That cap is shown as four caps in the schematic did you notice what type they are? Are they Compulytics? Most manufacturers suggest a 10 year field life for electrolytic caps in light duty applications. Electrolytic caps in high temperature applications are rated for life in hours, typically 1000 to 3000 hours at very high temps.

>Saturation is not an issue right now cuz I don't have the

>right woofers. Notice in the schematic that the tweeters are

>just on a cap.. 6db/oct. In the AR3A I believe it was a 12 db

>network. Wonder if that would be beneficial from the point of

>protecting the tweeters...

The AR-3a schematic is on this site and it is also just a 6 uF cap with a 16 ohm pot. So the crossover is essentially the same. I believe the mid and woofer are also nearly the same and you could use the entire AR-3a crossover in order to eliminate the 5000 uF cap and auto-transformer. Another alternative is to wire the woofer XO directly to the input, retaining the fuse, and reduce the 5000 uF cap so that the auto-transformer is only used for mids and tweeters, if you wanted to minimize the number of changes.

Yes 12dB/oct would help protect the tweeters, but it has to be properly designed. I believe the 10pi and 11 use second order networks on the tweeters and there's no reason why you can't use the 10pi or 11 crossover, but if you change the tweeter, midrange changes should also be made including watching out for driver polarity.

>The midrange is more than 6db network but not a full 12... not

>sure if it's the same as the AR3a.

>

>If I was to eliminate the autotransformer would I have to put

>in some series resistance in the tweeter and the midrange

>lines to reduce efficiency? eg when you multiple woofers you

>get a 3db increase in bass frequencies for every doubling of

>drivers.. assuming impedance stays the same... does the same

>hold true for tweets and mids?

Yes exactly, so 1 to 2 is 3 dB and 2 to 4 is another 3 for a total of 6 dB. As I said you could use the exact AR-3a crossover and you'd just end up running the level controls much lower due to the 6 dB gain. I'd probably use Lpads (or switched pad type attenuators) rather than simple pots to maintain a more constant load to the crossover. A 4 ohm Lpad can be made by paralleling a stereo 8 ohm type. We would want to determine what load the AR3a XO saw with the pot in the center position, it might be as high as 6, this would be the number to match. An advantage of the auto-transformer is that it should provide a much more constant crossover point compared to pots, but an Lpad can come close.

Regards, Pete B.

[Wally]

>DC resistance and inductance from each tap on the

>auto-transformer to the common.

I'LL DO THAT WHEN I GET THE PROPER WOOFERS.

That cap is shown as four

>caps in the schematic did you notice what type they are? Are

>they Compulytics? Most manufacturers suggest a 10 year field

>life for electrolytic caps in light duty applications.

>Electrolytic caps in high temperature applications are rated

>for life in hours, typically 1000 to 3000 hours at very high

>temps.

IN FACT IT IS ONLY ONE HUGE 1200MFD COMPUTER TYPE ELECTROLYTIC.

>The AR-3a schematic is on this site and it is also just a 6 uF

>cap with a 16 ohm pot. So the crossover is essentially the

>same.

THEN I WON'T MESS WITH THE CROSSOVER EXCEPT TO REPLACE THE CAPACITORS WITH NEW FILM ONES FROM SOLEN.

I believe the mid and woofer are also nearly the same

>and you could use the entire AR-3a crossover in order to

>eliminate the 5000 uF cap and auto-transformer. Another

>alternative is to wire the woofer XO directly to the input,

>retaining the fuse, and reduce the 5000 uF cap so that the

>auto-transformer is only used for mids and tweeters, if you

>wanted to minimize the number of changes.

THATS ANOTHER GOOD IDEA I WILL EXPLORE WHEN I GET THE PROPER WOOFERS.

>Yes exactly, so 1 to 2 is 3 dB and 2 to 4 is another 3 for a

>total of 6 dB. As I said you could use the exact AR-3a

>crossover and you'd just end up running the level controls

>much lower due to the 6 dB gain. I'd probably use Lpads (or

>switched pad type attenuators) rather than simple pots to

>maintain a more constant load to the crossover. A 4 ohm Lpad

>can be made by paralleling a stereo 8 ohm type. We would want

>to determine what load the AR3a XO saw with the pot in the

>center position, it might be as high as 6, this would be the

>number to match. An advantage of the auto-transformer is that

>it should provide a much more constant crossover point

>compared to pots, but an Lpad can come close.

ONCE I MEASURE INDUCTANCE AND RESISTANCE I'LL TRY TO CALCULATE AN APPROPRIATE CAPACITOR TO DO JUST THAT.

I'M LISTENING TO THESE THINGS JUST THE WAY THEY ARE WITH THE MIDS AND TWEETS ON THE -6 AND -2 TAPS RESPECTIVELY. THE WOOFS ON THE 0 TAP. THEY SOUND SVERY SWEET. THE MID AND HIGH END ARE VERY SMOOTH. MUCH MORE LISTENABLE THAN THE ADVENTS OR THE AR'S. THE BASS IS NOT QUITE AS PROMINENT AS THE ADVENTS BUT THEY ARE ON THE FLOOR AND THE LST'S ARE AT EAR LEVEL ALMOST AGAINST A WALL. WHEN SOME DEEP BASS IS PRESENT IN THE MUSIC IT COMES OUT VERY CLEARLY AND SOLIDLY. I AM VERY PLEASED SO FAR BUT ANXIOUS TO HEAR THEM WITH PROPER WOOFS.

I'M LISTENING TO 'JAZZ AT THE PAWNSHOP' AND IT'S LIKE THE GROUP IS PLAYING AT THE OTHER END OF MY REC ROOM. I HAVE THEM AT THE NARROW END...12' BET THEY'LL SOUND BETTER AGAINST THE LONG WALL WHERE THE RIGHT AND LEFT MIDS WON'T BE BOUNCING OFF ADJACENT WALLS.

I'M DRIVING THEM WITH A McINTOSH C-28 AND AN MC-2105 AMP. IT'S A WONDERFUL COMBINATION.

WALLY

[Pete B]

>>DC resistance and inductance from each tap on the

>>auto-transformer to the common.

>I'LL DO THAT WHEN I GET THE PROPER WOOFERS.

We'd want to get the inductance of the auto-transformer alone, isolated from the rest of the system, this might be too much trouble. What would be interesting once you get the new woofers is to measure the frequency response from speaker input to the woofer terminals, and also to the mids and tweeters. I don't think there's a common ground in this system so you might need a floating meter.

> That cap is shown as four

>>caps in the schematic did you notice what type they are?

>Are

>>they Compulytics? Most manufacturers suggest a 10 year

>field

>>life for electrolytic caps in light duty applications.

>>Electrolytic caps in high temperature applications are rated

>>for life in hours, typically 1000 to 3000 hours at very high

>>temps.

>

>IN FACT IT IS ONLY ONE HUGE 1200MFD COMPUTER TYPE

>ELECTROLYTIC.

I wonder if this was replaced, I think 5000 uF is the correct value. Could explain the weak bass that you mention. I asked about Compulytics because these have a special construction technique that have many connections to the plates to lower ESR. They have much lower ESR than the typical non-polar electrolytic, around 10s of milliohms as compared to 500 or more milliohms for the typical non-polar electrolytic.

>>The AR-3a schematic is on this site and it is also just a 6

>uF

>>cap with a 16 ohm pot. So the crossover is essentially the

>>same.

>

>THEN I WON'T MESS WITH THE CROSSOVER EXCEPT TO REPLACE THE

>CAPACITORS WITH NEW FILM ONES FROM SOLEN.

I forgot to mention that you can do a quasi-second order system by using a larger inductor across the tweeter than would normally be used, say .5 to 1 mH. This keeps it first order around the initial rolloff point, but breaks to second order at much lower frequencies which can still cause heating and excursion. This should not change the system response since it alters the response of the tweeter well below the passband. A simple way to test would be to switch it in and out while listening to noise or music.

>I believe the mid and woofer are also nearly the same

>>and you could use the entire AR-3a crossover in order to

>>eliminate the 5000 uF cap and auto-transformer. Another

>>alternative is to wire the woofer XO directly to the input,

>>retaining the fuse, and reduce the 5000 uF cap so that the

>>auto-transformer is only used for mids and tweeters, if you

>>wanted to minimize the number of changes.

>

>THATS ANOTHER GOOD IDEA I WILL EXPLORE WHEN I GET THE PROPER

>WOOFERS.

>

>>Yes exactly, so 1 to 2 is 3 dB and 2 to 4 is another 3 for a

>>total of 6 dB. As I said you could use the exact AR-3a

>>crossover and you'd just end up running the level controls

>>much lower due to the 6 dB gain. I'd probably use Lpads (or

>>switched pad type attenuators) rather than simple pots to

>>maintain a more constant load to the crossover. A 4 ohm

>Lpad

>>can be made by paralleling a stereo 8 ohm type. We would

>want

>>to determine what load the AR3a XO saw with the pot in the

>>center position, it might be as high as 6, this would be the

>>number to match. An advantage of the auto-transformer is

>that

>>it should provide a much more constant crossover point

>>compared to pots, but an Lpad can come close.

>

>ONCE I MEASURE INDUCTANCE AND RESISTANCE I'LL TRY TO CALCULATE

>AN APPROPRIATE CAPACITOR TO DO JUST THAT.

The capacitor should be much larger than the midrange cap so as to not alter the midrange crossover response. The midrange cap is 50 uF IIRC, so 500 uF should be safe. We're trying to avoid the cost of the large 5000 uF Compulytic and reduce the amount of low freq going to the auto-tranformer. 500 is a good compromise.

>I'M LISTENING TO THESE THINGS JUST THE WAY THEY ARE WITH THE

>MIDS AND TWEETS ON THE -6 AND -2 TAPS RESPECTIVELY. THE WOOFS

>ON THE 0 TAP. THEY SOUND SVERY SWEET. THE MID AND HIGH END ARE

>VERY SMOOTH. MUCH MORE LISTENABLE THAN THE ADVENTS OR THE

>AR'S. THE BASS IS NOT QUITE AS PROMINENT AS THE ADVENTS BUT

>THEY ARE ON THE FLOOR AND THE LST'S ARE AT EAR LEVEL ALMOST

>AGAINST A WALL. WHEN SOME DEEP BASS IS PRESENT IN THE MUSIC IT

>COMES OUT VERY CLEARLY AND SOLIDLY. I AM VERY PLEASED SO FAR

>BUT ANXIOUS TO HEAR THEM WITH PROPER WOOFS.

>

>I'M LISTENING TO 'JAZZ AT THE PAWNSHOP' AND IT'S LIKE THE

>GROUP IS PLAYING AT THE OTHER END OF MY REC ROOM. I HAVE THEM

>AT THE NARROW END...12' BET THEY'LL SOUND BETTER AGAINST THE

>LONG WALL WHERE THE RIGHT AND LEFT MIDS WON'T BE BOUNCING OFF

>ADJACENT WALLS.

>

>I'M DRIVING THEM WITH A McINTOSH C-28 AND AN MC-2105 AMP. IT'S

>A WONDERFUL COMBINATION.

Good to hear your enjoying them and it's interesting to hear which taps people prefer.

Pete B.

[Wally]

>I wonder if this was replaced, I think 5000 uF is the correct

>value. Could explain the weak bass that you mention. I asked

>about Compulytics because these have a special construction

>technique that have many connections to the plates to lower

>ESR. They have much lower ESR than the typical non-polar

>electrolytic, around 10s of milliohms as compared to 500 or

>more milliohms for the typical non-polar electrolytic.

LOOKS ORIGINAL TO ME.

>I forgot to mention that you can do a quasi-second order

>system by using a larger inductor across the tweeter than

>would normally be used, say .5 to 1 mH. This keeps it first

>order around the initial rolloff point, but breaks to second

>order at much lower frequencies which can still cause heating

>and excursion. This should not change the system response

>since it alters the response of the tweeter well below the

>passband. A simple way to test would be to switch it in and

>out while listening to noise or music.

OK. ANOTHER OPTION TO EXPLORE. DO YOU KNOW WHO SELLS THE 15 OHM POTS...NOT SURE OF THE POWER RATING.

>

>

>The capacitor should be much larger than the midrange cap so

>as to not alter the midrange crossover response. The midrange

>cap is 50 uF IIRC, so 500 uF should be safe. We're trying to

>avoid the cost of the large 5000 uF Compulytic and reduce the

>amount of low freq going to the auto-tranformer. 500 is a

>good compromise.

I'M LEANING TOWARDS BYPASSING THE BIG CAP AND THE AUTOFORMER AND JUST PUTTING IN A COUPLE OF MID AND TWEETER POTS LIKE IN THE AR-3'S.AS PER PREVIOUS NOTES,WITH THE 4 MIDS AND 4 TWEETS THERE SHOULD BE MORE THAN ENOUGH MID AND HIGH TO OVERCOME THE DEFICIENCIES OF THE ORIGINAL AR3A AND THE POTS WOULD GIVE THE OPTION OF BACKING THESE OFF TO AR3A OR AR3 TYPE RESPONSE. JUST THINKING THIS APPROACH WOULD LOAD THE POWER AMP LESS AND MAYBE MAKE THE IMPEDANCE CURVE MORE EVEN.

GUESS THE IDEAL WOULD BE TO BRING OUT MULTIPLE TERMINALS TO THE BACK AND THEN I COULD WIRE IN DIFFERENT CONFIGURATIONS FROM OUTSIDE THE CABINETS.

WAITING TO GET THOSE 12'S TO GET A BETTER IDEA OF THE ORIGINAL SOUND OF THE LST'S.

WALLY

[Pete B]

>LOOKS ORIGINAL TO ME.

I noticed that you gave the serial numbers for your LSTs is there anything that could explain the different cap? Early/late production, they're not LST 2s are they?

>OK. ANOTHER OPTION TO EXPLORE. DO YOU KNOW WHO SELLS THE 15

>OHM POTS...NOT SURE OF THE POWER RATING.

I really strongly suggest a 4 ohm L-pad, or even better a switched L-pad type attenuator.

>I'M LEANING TOWARDS BYPASSING THE BIG CAP AND THE AUTOFORMER

>AND JUST PUTTING IN A COUPLE OF MID AND TWEETER POTS LIKE IN

>THE AR-3'S.AS PER PREVIOUS NOTES,WITH THE 4 MIDS AND 4 TWEETS

>THERE SHOULD BE MORE THAN ENOUGH MID AND HIGH TO OVERCOME THE

>DEFICIENCIES OF THE ORIGINAL AR3A AND THE POTS WOULD GIVE THE

>OPTION OF BACKING THESE OFF TO AR3A OR AR3 TYPE RESPONSE. JUST

>THINKING THIS APPROACH WOULD LOAD THE POWER AMP LESS AND MAYBE

>MAKE THE IMPEDANCE CURVE MORE EVEN.

I'm working on a brief web page with my suggestions, almost done.

>GUESS THE IDEAL WOULD BE TO BRING OUT MULTIPLE TERMINALS TO

>THE BACK AND THEN I COULD WIRE IN DIFFERENT CONFIGURATIONS

>FROM OUTSIDE THE CABINETS.

Yes would make experimenting much easier.

Pete B.

[Wally]

is

>there anything that could explain the different cap?

>Early/late production, they're not LST 2s are they?

Definitely LST's 4 mids 4 tweets, woofer hole is for a 12" woofer.

The 10"s in it are on 10-12 adapters...

Re the cap... check the schematic.... if you were to take 4 1250's in a series parallel you would have a total of 5000 ufd but only 1250 effective ufd because of the series parallel config. Maybe they just cut costs in later versions and just put in the one cap figuring the non linearity of the electrolytic would not be audible at those low freqs and maybe there is less effect at mid and high freqs with this large a cap????? I'll take a good look at the cap when I mod the unit. Maybe it's 4 caps in one giving 1200 ufd NP created by 4 1200's in series parallel????

>I really strongly suggest a 4 ohm L-pad, or even better a

>switched L-pad type attenuator.

Where do you get a 4 ohm L-pad... plus will that throw the original crossover freq off cuz it was based on the 15 ohm pot?????

>>THINKING THIS APPROACH WOULD LOAD THE POWER AMP LESS AND

>MAYBE

>>MAKE THE IMPEDANCE CURVE MORE EVEN.

>

>I'm working on a brief web page with my suggestions, almost

>done.

I'm looking forward to that. Let me know as soon as it's done.

>>GUESS THE IDEAL WOULD BE TO BRING OUT MULTIPLE TERMINALS TO

>>THE BACK AND THEN I COULD WIRE IN DIFFERENT CONFIGURATIONS

>>FROM OUTSIDE THE CABINETS.

>Yes would make experimenting much easier.

As soon as I acquire a proper set of woofers I'll start with the mods.

>Pete B.

[Wally]

OOPS,

My mistake, the IC150 doesn't have a processor loop, it's my Hafler that does. Nevertheless it's a nice unit to mod because of the size of the chassis.

regards, Wally

[Wally]

Hi Pete,

I installed the Tonegens that I got from Bret on this forum. They sound great and I'm anxious to do some of the other mods we talked about. Will have to wait till after I'm moved next month.

Did you ever get your information put together regarding L-pads and fixed resistor networks etc?

regards, Wally

[Guest Bret]

>I installed the Tonegens that I got from Bret on this forum. They sound great and I'm anxious to do some of the other mods we talked about. Will have to wait till after I'm moved next month.<

In the interest of full disclosure, you should have mentioned that I told you I had nightmares about those in LSTs, lead you to a pair of something closer to originals, and really did my level best (no pun intended) to talk you out of them.

I'm glad you are enjoying them, but an LST really does deserve the originals. I think you'll be surprised.

Bret

[mluong303]

Hi, Wally

Email me directly and see if I can help you out.

Minh Luong

mluong303@aol.com

[Wally]

LOL

That is absolutely true. I have never encountered such a difficult salesman. He did everything he could to NOT sell me those Tonegens.

I am very satisfied with the LST's now and if they can be improved with original drivers, that is something to look forward to.

Thanks Bret for all your suggestions and reviews of the various AR's that you have had.

I swear those LST's are bassier every day.... imagination or are they being 'broken in'?????????

[Pete B]

Hi Wally,

I've gotten busy with some other work, I am almost ready with the LST ideas on a web page. Let me see what I can do in the next week or so.

Good to hear about the Tonegens. I'd be very interested to know what the closed box resonant frequency is for the Tonegens in your LSTs, can you measure it? I'd suggest directly across the woofer terminals in box. Don't know if your up for a full measurement of T&S parameters?

You asked about 4 ohm L-Pads, the two sections of a stereo 8 ohm L-Pad can be wired in parallel to get a 4 ohm unit, but as I've said I prefer switched pads:

http://www.partsexpress.com/pe/showdetl.cf...tnumber=260-260

Regards,

Pete B.

>Hi Pete,

>

>I installed the Tonegens that I got from Bret on this forum.

>They sound great and I'm anxious to do some of the other mods

>we talked about. Will have to wait till after I'm moved next

>month.

>

>Did you ever get your information put together regarding

>L-pads and fixed resistor networks etc?

>

>regards, Wally

[Wally]

Hi Pete,

I'll try to do Fb tomorrow. I'm in the process of getting ready to move and I can't remember if I already packed my sig gen. I'll look tomorrow and let you know.

Bret has been very supportive and helpful and tried his darndest to discourage me from using the Tonegens. I couldn't get an 'old' set of AR 12's so I figured the tonegens would be better than the 10" substitutes that had been kludged in the enclosures on adapter rings similar to the old Advents.

The bass still semms very light compared to a pair of Celestion DL-10's that I'm comparing with. Since I don't have a pair of AR-3's to compare I don't know if they are 'light'

Should be getting a pair of AR12's next week so I should have a better basis for comparison. Again maybe it's just a matter of checking out that big ca in the xover or eliminating it from the woofer path..

All that will have to wait until I am relocated but I'll do the Fb if my generator is still unpacked.

regards, Wally

>Hi Wally,

>

>I've gotten busy with some other work, I am almost ready with

>the LST ideas on a web page. Let me see what I can do in the

>next week or so.

>

>Good to hear about the Tonegens. I'd be very interested to

>know what the closed box resonant frequency is for the

>Tonegens in your LSTs, can you measure it? I'd suggest

>directly across the woofer terminals in box. Don't know if

>your up for a full measurement of T&S parameters?

>

>You asked about 4 ohm L-Pads, the two sections of a stereo 8

>ohm L-Pad can be wired in parallel to get a 4 ohm unit, but as

>I've said I prefer switched pads:

>

>http://www.partsexpress.com/pe/showdetl.cf...tnumber=260-260

>

>Regards,

>Pete B.