Thiel Owners

jafant - the pleasure is mine. Good work here, guy.

magnet7 - my latest schematic (22dec'87) shows an 8uF (not 8.2) which had replaced the original 7uF spec.

magnet7 - yes, that 8uF tweeter blocking cap is the best bang for the buck. Psychoacoustically, its function range in the midrange and treble is where our hearing is most sensitive. 

@tomthiel 

Tom, can you confirm that in your view the most effective (both, sonically and economically) upgrade for 3.5s is the 8.2uf cap replacement in the tweeter feed?

tomthiel

I hope that you are well and ready to kick off Spring starting this Sunday.

Thank You for being a strong supporter in this thread and the advancement of our beloved Thiel Audio loudspeakers.

Happy Listening!

magnet7

Good to see here again. Thank You for the 3.5 upgrade, update.

I know that Tom is working very hard to deliver a viable upgrade path 3.5 loudspeaker. Stay tuned.

Happy Listening!

jeff_pvd

Thank You for the follow up and citing Serial Numbers (S/N) on your speakers.

Those are nice, low, numbers. Good to read that a Rotel receiver can drive the 03.

Happy Listening!

For those interested, the original 03 EQ was similar to the 01 as a fixed point boost at 30Hz, enabling the speaker's -3dB point at around 27Hz while maintaining 90dB sensitivity at 8 ohms (6 ohms minimum). Those early EQs had less sophisticated circuitry and implementation, with electrolytic caps in the signal path and so forth - creating a transistory veil on the music. Each generation got better with the CS3.5 becoming direct-coupled.

Jeff - you're not alone in preferring the direct path and sacrificing the deep bass for more transparency. You might consider the CS3.5 in your replacement search. The EQ is getting upgraded well above stock and the speaker is in line for significant driver and crossover upgrades.

tomthiel wrote:

"Jeff - my memory was unclear about the ported 03. Please confirm NO equalizer."

My ported 03s came with the Thiel equalizer. Early on I made the determination that I liked the sound/setup better without the equalizer in the pipeline. I no longer have the EQ box, I should have hung on to it. 

Jeff - my memory was unclear about the ported 03. Please confirm NO equalizer.

BTW, it's great to know these speakers have given you joy for so long. They were made in our first garage shop on the little farm outside Lexington, about the time we were building the new 16' x 28' addition onto the original dirt-floor 15' x 22' garage. Memory Lane Lives. 

Good weekend too you all.. 

Tom gave me some tips on cables for my speakers and I must say that they are both more open ( the one on the right was a bit cramped/ held back and on the first listen benefits more than the left , but both are more present with my self made new cables. )

I've got the electronics for my surround speakers nearly finished and ask in their own little boxes (filled with holes for venting). Just need one or two resistors and caps and Rob to finish my coax...

****** Weekly reminder ******

Just to remind those willing to upgrade their 2.4

Clarity Caps PUR 14 uF@630 VDC for €165,00 / piece

Clarity Caps PUR 28 uF@259 VDC for €142,50/ piece

This would total in USD something around 670 for the set

******** PM me if interested ********

Cheers

Pieter

@tomthiel - Thank you so much!!  

I'm aware of the non-essential importance of shunt electrolytics in the woofer cell. Precisely for this reason I have already ordered two 8.2uf ClarityCap CSA polypropylene capacitors to replace the 8uf Solen caps in the tweeter path. From what I understood these units are the ones on which to invest the most in terms of cost /sonic results.

As for the other electrolytics:

- the two 100uf caps in in the midrange cell (one in series and the other in parallel shunt), essentially for budget reasons, I thought  to replace them with new 100uf Mundorf electrolytics (RAW series - ECAP 100), and to replace the 1uf Solen with one 1uf “Audyncap Q4” (polypropylene). The small 12,000pf bypass polystyrene capacitor would remain in place;

- I would follow the same path for the 100uf electrolytic in the tweeter cell: replacement with a new Mundorf electrolytic of same capacity and replacement of the 1uf Solen with a new 1uf Audyncap Q4, keeping the small 12000pf polystyrene cap.

This is why in my previous post I asked for advice only on how (and with which units) to replace the woofer capacitors. However, if collective knowledge / experience of this Group believes that I’m taking the wrong path as regards the intervention on the crossover, I still have time because I have not yet sent the order for the new capacitors.

Thanks

    
tomthiel - Thanks for the history, makes good sense! 

BTW, the 03s I have (SN 0287, 0288) have a round 2.5" port below the woofer on the left side. 

Jeff - here's a lesson from Thiel history. All our products shared the same goals of flat frequency, phase, time, and dynamic response. The family signature is quite similar between models. Also, along the time-line, new technologies were invented and incorporated, so a newer product will always be more sophisticated than prior ones. Higher model numbers get you more bass. In your particular case, you will sacrifice bass extension and power going from your equalized, sealed 10" woofer to the 2.4's reflex 8" woofer. (Unless you weren't equalizing your 03.) The 2.4 is a highly mature product, whereas the 03 is the first generation of its format. Huge difference in subtlety and sophistication, but very similar family resemblance.

Notes about your 03. Only 500 pair were made before the upgraded 03a (2500 pair.) Your 03 is the base on which Thiel succeeded. Its phase/time coherence was unique and the equalized bass was unusual and powerful. They earned immediate distribution and reviews in Europe which seeded interest from east coast US dealers - and the rest followed. The 03 is quite rudimentary compared with later models, but in 1978 it shone quite brightly.

jafant  - Thanks for your response!

After looking at all the Thiel models on https://coherentsource.wordpress.com I can see why the CS 2.4 would be considered the sweet spot, the most modern model before the price starts doubling. 

I know this is a hard / subjective question to answer, but I'll ask anyway :) If I go from my 03s to something like the CS 2.4s, what can I expect? Will it sound like a completely different speaker/a huge jump in performance or just a nice refinement of what I already have?

As for my system: I'm guessing it's rather basic or maybe even "crude" to what others have on here, but I have a good ear and find it highly enjoyable to listen to. 

I  play mostly high quality recordings / files from a MacBook Pro feeding a Schiit Modi Uber DAC then to a Rotel 1052 receiver (100 wpc) out to the 03s.

magnet7 - Others here might help you find your best brand fit. Here’s my broad input. Those woofer electrolytics are in shunt (shaping) resonance circuits which are the least sonically important. The Solen 1uF bypasses are very good. The styrene ultra-bypasses are extravagantly good. Those woofer shunt circuits are least worthy of expensive audiophile electrolytics.

On the other hand, the caps in the midrange circuit are of greater sonic importance. The 100uF electrolytic mid feed cap is worthy of the best cap you can afford, perhaps a ClarityCap 250 volt (or $higher) CSA with a very good 1uF bypass and then decide by ear to keep or toss the styrene bypass. Similarly the 100uF mid shunt.

The tweeter also has a 100uF electrolytic feed, which is at least as important as the midrange.

Short story, concentrate your budget on the upper drivers. I suggest looking at Nichicon for those woofer shunts. (high quality pro-level audio cap.)

Hello everybody.

I would like to ask your opinion on the crossover update of my CS3.5.

I have already ordered (and am awaiting delivery) two 8.2uf ClarityCap CSAs, which will replace the two equal capacity Solen polypropylene caps installed in the tweeter’s cell (these are the two units to which - following the precious advice of Tom Thiel - I want to allocate the largest budget).

The doubt concerns instead the replacement of the two electrolytics in the woofer cell. As you may know, in the latter there is a 66uf electrolytic cap (branded "Versa-Tronic") and another 24uf electrolytic cap (also branded Versa-Tronic). These two capacitors are bypassed by a 1uf polypropylene (Solen) and a small 12pf polystyrene.

Now, as the two electrolytics mentioned above have come to the end of their service period I would like to replace them.

With which units do you recommend replacing them, having to replicate the overall capacity of the two groups of capacitors (that is 25.012uf (24uf + 1uf-12pf) and 67.012uf (66uf + 1uf ​​+ 12pf))?

Thanks to everyone who will want to advise me!

Happy Friday! All

jeff_pvd

Welcome! Good to see yo here today. Thank You for sharing your Thiel 03s experience.  After 34 years, you are certainly due for an upgrade. IMO, the sweet spot is a pair of CS 2.4 loudspeakers. These are easily found all over the internet.

Model CS 2.4 can be placed 8-10 feet apart. Then, 2-3 feet away from back walls/side walls. This particular speaker sounds great with as little as 75 watts up to 200 watts per channel (wpc). Again, easy to drive and easy to place without too much fuss. Most sellers are honest about the condition of a demo/used pair of Thiel Audio loudspeakers.

What other gear is in your system? I look forward in reading more about your Musical taste.

Happy Listening!

Looking to upgrade my Thiel speakers - What should I get / look for?

Back in 1988 (when I was 23) I was looking to upgrade my Polk Audio floor standers, the Polks had plenty of bass and treble but lacked detail. I made my way over to a small audio store in Cambridge, MA  (Q Audio - still in business after all these years) and saw a pair of used Thiel 03s. I listened to the Thiel’s briefly, was impressed but the setup in the store was less than ideal to make any sort of sound judgement. The salesperson very kindly told me “take them home and try them out for a few weeks, if you don’t like them, bring them back and i’ll happily give you your money back no problem!” I took them home and have now been delighted by them for 34 years! What I noticed right away was their uncanny ability to reproduce the human voice so naturally. The Thiels are not just “speakers” but really fine instruments that come alive with the right recordings. After many years of use I had the foam around the woofers expertly replaced. A few years ago I also added a subwoofer to the 03s, extending the bass but more impressively adding more 3-dimensionality to the sound stage. 

After 34 years, I’m feeling the itch to upgrade:) I need some help. I want to buy a more modern/advanced pair of Thiels (used of course) in the $2K range. I have a few questions If anyone has some input:

1) When evaluating a used pair, what should I look for a far as defects, things that might to be fixed? Ideally I don’t want to fix/restore too much.

2) My current listening room is narrower than ideal but my 03s work just fine in the space. Do all the models require the same space or are some better suited to narrower L to R walls? I can sit as far back/away as needed. 

3) Is there a particular model in my price range that stands out?

My idea is to look at any that come up for sale within 100 miles away to check them out in person. It may take a while for the right ones to appear.  

Any thoughts are much appreciated, I found this wonderful forum a few days ago!

~ Jeff
 

@vair68robert thank you very, very much👍🏼🍻

pieper

partsconnexion says that the resistors are a few weeks out if you can wait ,

I had to contact about purchasing 8 Mundorf electrolytic capacitors , so I asked they about your resistors .

Excellent discussion Guys , on the CS 2.4 / CS 2.4SE loudspeaker.

Happy Listening!

I see MRA-12 12 Ohm on Sonic Craft and Parts Connexion websites

???

If *I* was going to spend $25 per resistor, I would get Path and put them only on the coax feeds. I recall looking into this and some of the values are not available in single resistors. And it gets super complicated, with the available Path values,  trying to get the proper values by combining resistors.

It looks like it's not super hard to make your own graphite resistors but it probably takes *many* attempts to get the correct value, especially as a matched pair!

@vair68robert ... I already checked there it seems. They don't have the 12 Ohm 12 Watt resistors, unfortunately..🤷🏻‍♂️

@vair68robert thank you. I'll look.

@beetlemania I'll keep that in mind when I get around to the 2.4's. I had my eyes on some hand made resistors from Poland.. think they would come down to 20-25 dollars a piece... 

pieper

have you tried Partsconnexion ? 

they list that they are in stock .

Some of the power resistors can benefit from 25 watt versions, thus 2x12watt. This resistor thing was a short suit for Jim (in my opinion), since the compact layouts can only afford so much real estate. Modeling software can ID those candidates; so can pink noise and a thermometer (or fingers.)

Beetle - I do remember the aluminum cooling bar mis-step. Moving air and greater distance work better.

@tomthiel thanks for the information. Heat management was definitely on your radar when I did my build. You’ll recall an early solution that we abandoned. But it sounds like you continued to work things out. I hope you can share this with the world sooner than later (products or “how to” manuals).
 

@pieper1973 when I upgraded the sandcasts on my OEM boards (sourced from FST), I bought all Mills in identical values. But when I did the full rebuild, Tom had me parallel 60.4 ohm Mills for the 30 ohm position - more surface area for cooling that big resistor. The downside is it costs twice as much. But there is a sonic benefit to running in parallel, at least for bigger resistors. 

@beetlemania 

Among others I have the 2.4 ..

The 12 Ohm is needed for my one point monitor with the SCS3-N Thiel coaxes.

Audi, I don't want to combine resistors to get to 12 Ohm. I'm just looking for a good substitute for the Mills, if anybody knows of one.. 

Beetle - I looked extensively at thermal dynamics as a source of 'aural congestion', drifting crosspoints, etc. That's where the new layouts came from, which have all the resistors separated from caps as well as positioned over ventilation holes in the board for natural convection, and moved either to the exterior of the cabinet or to separate XO enclosures. The hookup wire(s) also mount to pin-type heat exchangers close to each driver to drain voicecoil heat directly through the lead wires. Taken together the thermal management significantly improves dynamic range and 'sonic orderliness' during high-power use. The small-signal Thiel reputation got bigger.

My investigation began by remembering 'warranty claims' for melted caps and charred XO boards in the old days. In my power tests, some resistors got too hot to touch. Series coils also get hot - I put them on 3 rubber feet for all-round radiating and convection. My tool of choice is a non-contact infra-red thermometer to identify small scale/ local differentials. That led to some heat-sinks being added in-line on the XO board for dissipation before entering caps. I don't remember at what stage all that investigation stood when we hot-rodded your 2.4s. There's always more. 

Nice tweak, @tomthiel Curious to hear the back story on how you discovered that.

@pieper1973 you have CS2.4, right? Why do you want 12 ohms?

Also, I forgot to mention one of the Mundorf lines is comparable to Mills . . . It’s a re-badged Ohmite.

pieper

try using parallel resistors 

http://www.sengpielaudio.com/calculator-parallel.htm

a 20 and a 30 = 12

Adding to Beetle’s excellent summary, here’s a cheapskate trick for the Thiel resistors that you might keep.

Turns out, a big part of those resistors’ ’sonic problem’ is the thermodynamics due to their mounting. They are non-inductive wire-wound with current flowing around their coil circumference, dissipating into the ceramic body. The bottom of that body is glued to the panel, creating a large differential in wire heat distribution. Solution is to mount that same resistor on an edge rather than a flat. Put the edge on Mortite / BluTac pads for even better results. Cheap fix, much of the improvement of Mills, suitable for woofer and midrange. Spend your savings on a Path, etc. for the 12Z tweeter feed.

@pieper1973

Are you in the US? Sonic Craft is your friend. They stock MRA-12s in all the values used in the CS2.4 although you do have to mix and match the old Mills (brown body) with the newer Vishay-Mills (black body). Fast shipping, fair pricing, and excellent service. IIRC, I paid for the mid-grade level matching and they gave me the full set measured at better than the top-grade level matching.

If you are really stuck, the only thing comparable, from my extensive research, is the Ohmite. Wilson uses Caddock but I could never figure out anything that would be suitable in the CS2.4. If you have really deep pockets, you might try Path or Dueland graphite resistors. People say they are the best. They better be at those prices - 5-8 times the Mills! At that’s if you can get the correct resistance in a single resistor. You have to get really creative running in series/parallel to get the proper values. Other than Mills, those are your choices. Otherwise, just keep the OEM resistors.

Good day to you all..

I'm having a problem getting my hands on Mills resistors 12 Ohm @12W.

The sender has given me a very long list of other brands..

Anybody here recommend a substitute for the mills at same price range and sonic performance?

Thank you

 Pieter

@tomthiel 

Thank you for the detailed answer. Interesting observation re: Thiel v Vandersteen house sound.

Those 7 uF PURs are the first I’ve seen in that capacitance value. Will be interesting to see if the North American retailers stock those. In the meantime it looks like @pieper1973 has a lead on getting the 14 and 28 in single caps.

If I ever make any further mods it will probably be to try an ultra bypass (eg, Jupiter copper foil), Path graphite resistors in the coax feed path (really tough to get the correct values at all positions), or, if your reports are over the moon, PUR in the coax feeds. Regardless, I’m sitting on some tricked-out, sweet-sounding CS2.4s.

vair68robert,

Please let us know what the results turn out to be. 

Tom T. & Duramax747

You got me rethinking the shunt circuit on the 2.7 , so I'm sticking with 

the 220uf  6% ERSE and the 330uf 10% changing it from a Topmay ? %

to an ERSE , I was thinking 2 x 220uf 6% and 110uf 6% .

But I will be changing the 400uf ? % Topmay to 2 x 200uf 6% ERSEs .

I also ordered new 6 x 15uf 400V PulseX caps up from 250V .

Thanks again for all your insight .

Rob

In most all applications I never liked the addition of bypass caps especially those on speakers. At one Thiel dealer in 80s we did a comparison of bypass caps on and off the result was they were left off.  For what its worth 3 of the 4 listeners on that day.continued on in the business at least one to this day and still dug in. Tom D

@beetlemania

re: " Curious if you have an opinion or knowledge about how to pair "main caps" if the full capacitance is not available in a single cap. Is it best to optimize balance between caps (eg, 7+7=14) or is there some degree of leeway (eg, 10+3.9+0.1)?"

My opinion is based on Thiel experience and related observations - both approaches are valid, but will produce slightly different sonic signatures. I believe the cascading bypass format compensates for deficiencies in the large cap which produces dielectric cycle anomalies (charge lag, erratic discharge, Effective Series Resistance irregularities relative to power levels, etc.), along with possible smoothing of the signal in general.  A small cap is inherently less reactive, plus a higher quality small cap is more affordable considering budget constraints. As you have previously mentioned, Thiel’s 1uF bypass cap might sometimes introduce less-than-best characteristic balance when bypassing at greater than 10% of the base cap value. We arrived at our format because we developed that great 1uF tin foil / styrene film cap for the CS5, bought 6-figures of them, and put them to work wherever they made an improvement (that we could afford.) Our main (base) cap was a single cap unless its value exceeded 100uF, where the deleterious secondary effects broke through. In those cases, we used single value multiples. You’ll see ganged 100uF caps (often electrolytic) bypassed by a good polypropylene, bypassed by the great (yellow) 1uF tin/styrene. 100uF was the maximum cap value we identified from listening, and same-value was identified as more correct than cascaded values.

Note this scheme runs contrary to common practice. Note the CS2.7 (outsource engineered after Jim’s death) uses a 400uF lytic in the midrange feed (400E/15PP/1S) and other large, cascaded lytics in that shunt circuit (330E/220E/15PP.) That scheme differs from Jim’s. Note that people who prefer the 2.7 sometimes note they like the "smoothness" or "refinement" of that model which may be attributable to this cascaded approach. Note also, that Vandersteen employs such a cascaded-value, multi type approach to cap bundles. I have wondered if that difference might be a significant contributor to the obvious character difference between Thiel and VdS. The two brands share very similar philosophies and solutions down to wire configuration, but exhibit very different personalities. Jim’s engineering approach was always to identify the solution that addressed the hard-core principles most directly, optimize the particulars and confirm by ear that the most accurate solution had been found. Little to no slack was cut to make harsh recordings sound smoother or mitigate other signal chain problems.

In summary, I would choose the 7+7 option as truer to Jim’s approach. There is, of course, leeway and your other string presents the option of using a CMR (PUR+) as the 0.1uF value without breaking the bank.

If you climb back into your 2.4s and try these options, let us know what you learn. No end to the fun.

prof

out of curiosity what 5751 tube are you using ?

I've had an interesting time tube rolling with my Conrad Johnson Premier 12 tube monoblocks.

Same ones I drove the Thiel 3.7 and now my 2.7s.

When I had both the 3.7 and 2.7 in the house I was trying to decide which one to keep.  One of the distinguishing factors is the 3.7s sounded like they were: a bigger speaker.  Even though by specs only slightly extended further than the 2.7, there was a sense with the 3.7s of the proportion of the sound being a big different.  Bass went a bit deeper, the scale was a bit larger on everything.  The 2.7s seemed like putting a bit of a girdle on - like the bass frequencies were lifted slightly upwards, putting more emphasis on the punchiness of the mid-bass.

I finally tried replacing the 6550 power tube on my amps with the larger more powerful KT120 tubes.  What a difference!   Bass feels deeper, the scale of everything - soundstage, image sizes - expanded.  Now the 2.7s truly remind me of the 3.7s in that sense.   Pretty amazing.

Rob - I can recommend the SonicCap from Sonic Craft that still has the old aspect ratio. Anything Sonic Craft carries has been carefully considered and chosen.

Dear Tom, first of all I must tell you that I am honored to be able to talk directly with you on my beloved speakers.  Also wanted to thank you for the truly kind and thorough preliminary answer you gave me. 

I will definitely proceed to ask you questions on specific aspects via pm.

Thanks again

@tomthiel 

@duramax747   contact Tom PM ,  he's been of great assistance to me .

duramax,  I am now going to wait for the PUR series for the 4 x 1uf caps needed for the tweeter/mid boards , they solve the size dilemma the I was agonizing over ,

as well as being an upgrade to the upgrade I was planning .

Still searching for an upgrade to the 15uf caps = in size to the ERSE pulse X caps 

Stefano - Here are some thoughts from having owned, listened to, appreciated and messed around with CS3.5s for decades. You are correct that anything you do will have sonic consequences; and also that some of those consequences will take you closer to the speakers’ original performance. Regarding the tweeters, unless you are hearing problems, I recommend you follow the advice to keep the 28/2s as backups. If you swap, see if Rob at Coherent Source Service can renew your ferro-fluid in your originals to save them as backups. Those VersaTronics caps are high performance, long-life caps. I don’t know of a single failure. However, 40 years is considered their estimated service life, and you are getting close. Some of those electrolytics are in signal paths where their failure would wipe out their driver; so I would replace those for safety. Rob or I can coach you; A’gon disallows sending schematics, etc. Note the 3.5 was the last product with the ultra-bypasses - styrene .015uF around PP 1uF. Great caps, keep them. Also keep your hookup wire.

Caps: better caps exist today and caps are an expensive upgrade. Your biggest bang / buck is to swap the 8uF tweeter feed for a ClarityCap CSA or PUR. These caps will not alter the ’house sound’ whereas other brands will.

Resistors: Jim developed those non-inductive ceramic resistors and they’re better than normal sand-casts. At the time we considered better resistors, but budget prevented their inclusion. I highly recommend swapping at least the series resistors, especially in the midrange and tweeter with Mills MRA-12s. Pretty short money, same circuit performance, sweeter sonics.

Binding posts: If your plastic-cap binding posts work, keep them. They are better than later big, brass posts which were Kathy’s capitulation to market perceptions.

Note: XO values were weaked end of 1987, you want the revision. What are your serial numbers?

Grille frames: This suggestion is just that, offered for general understanding. Those frames cause diffraction, but the fabric was considered in final voicing. IF your room is well damped (soft stuff, especially at wall reflection points), the difference in frequency response is often OK when bare. In that case, best performance is to create a grille frame that functionally fills the baffle edge voids, but eliminates the outer frame members. Conceptually, the new frame would keep the base perimeter and chop off the aerial parts. The long side struts would be rounded over to finish the curve of the baffle. Affix in place with Mortite or BluTac. You improve the anti-diffractive base function and eliminate the diffractive aerial elements.

Equalizer: The equalized bass was fundamental to Jim’s vision - it was abandoned due to market forces. It produces more integrated, better performing bass than the later reflex system. The EQ can be substantially improved (I am close to an available product.) Resistors replaced with metal film, Transistors replaced with lower noise, higher performance, maintainable versions. Caps upgraded as appropriate. Power supply redesigned as regulated rather than present unregulated circuit. Original all-discrete, Star Darlington, direct-coupled design remains. All in, big step up.

There are other hot-rod tweaks which we can discussed via PM if you wish. I posted all this detail for all you who might have been wondering.

Good morning everyone,

… first post here, but I have been reading you very carefully for some time. 

The question is about the possible crossover upgrade of my cs3.5.  
Currently the speakers are open for maintenance and therefore with possible access to the crossovers. The crossovers are still fully standard and  Rob Gillum tells me that the electrolytics (versa-tronics) even after all these years should be ok. 

That said, what do you suggest I do: replace the caps and also the resistors currently installed?  Which products in particular do you suggest and of which capacities for the 3.5?  Keep in mind that I absolutely do not want to alter the tonal balance  conceived by Jim Thiel. What I would like to do is restore the speakers in question to their original splendor or even improve them, but always keeping the original timbre imprint of the 3.5.  

Another doubt concerns the opportunity to mount some NOS D28/2 dynaudio tweeters that I managed to find. 

The technician who works on the speakers advises me not to install them  saying that the current ones are in good working order and to keep the new units as a reserve (in order to preserve the tonal balance of the speakers that could be altered installing new drivers). That leaves me a bit doubtful because it seems strange to me that the frequency response of the original tweeters has not dropped in a speaker of over thirty 'years, if only for a deterioration of the ferrofluid. 

I am eagerly awaiting your indications on what you believe to be the most appropriate approach. 

Thanks in advance
Stefano

vair68robert,

Do you have a schenatic for the CS2.7 crossover. I have a few boxes of cpas I think I could find those values. 

Happy Friday! ALL