Thiel Owners

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

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 - Yes, I know that according to the scheme it should be an 8uf.  I ordered the 8.2uf because the Clarity CSA does not exist in 8uf, only in 8.2uf.
The technician who is helping me with this upgrade project says that a difference of 0.2uf is not relevant.  What's your point of view?

@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?

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!

@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

Does anyone know the capacitance  of the 6 small polystyrene caps in  3.5’s crossovers?  

In the crossover schematic in my possession the capacitance of these units is not indicated, they are instead identified only with the letter "S" (which perhaps stands for styrene). 

The actual units installed in my speakers have the writing "ASC 12000H" (they should therefore be 12000 Picofarad capacitors, built by ASC Capacitor), but according to what can be found on line these caps should be 15000pf.

Therefore I’d like to ascertain the exact capacitance and brand of the stock units installed by Thiel (in order to ascertain if my capacitors are original or have been replaced at a later time). 

Thank you all 

And … are they Picofarad or Nanofarad?