[Hobbsmeerkat]

The newest video for anyone that missed it:
https://youtu.be/ZabTPk4XxBk

I took on the upgrade for these speakers and figured I would share some of my thoughts on the before/after results on these speakers.



Out of the box, these were not fun to listen too.. they were dull, unfocused and really muddy. It was easy for elements of music to get lost, especially in more complex or layered music. Nothing had a solid placement within the soundstage it was fuzzy at best, assuming you could even hear it. After about 5 songs I had enough. 

Onto the upgrade!
Spent the next couple days disassembling the speakers, designing a crossover board for it and putting the boards together.



The customer wanted top-level parts for the upgrade so thats why it includes miflex caps.

The new board is actually larger than the original, and only just fits into the woofer hole... With maybe 1/4 inch to spare... Fits onto the same place the stock board did. I used a combination of 3M "heavy duty" adhesive strips and a single screw I placed in the middle of the board to secure it to the cabinet.

I used a few more of our mounting screws to fill in the holes in the back left behind by the crossover boards, drilled out the bottom holes in the rear cup to fit the tube connectors and secued them with zip ties and hot glue, then ran the posts and tubes in parallel so the customer can easily swap back and forth if they wish.



Order: binding post > tube connector > crossover so the binding post connection doesn't interfere with the tube connectors connection.

I have some butyl damping material I used for the stamped-steel frames and that really quieted them down, and did the same for the long ports in the cabinet

I then pulled out the remaining stock insulation and lined them with norez. Added some polyfill to the upper secition and put the stock felt stuffing back over the crossover.

Attached the drivers and put them back up on the stands for some more listening.

WOW. These things really came to life.. you would bever know that they were the same speaker.. they no longer sound anything like they used to. All of the lost details were present and everything was focused and clear, right where it should be. I listened to them for maybe about 2 hours? They were a lot more fun than they were before the upgrade.
Getting rid of the felt on their baffle also really improved their overall soundstage presentation.

I'm really impressed how they turned out.



This is what we found worked best with the NoRez on the outer face to allow the speaker to work with the grill.

Here are the measurements with the grill before the norez (green) and after (Red)



Cheers! 

[Tom Bombadil]

Interesting.

I have owned a pair for about 25 years. 

Out of the box they were as you described - dull, boring, lifeless.  I couldn't believe it as I had heard a pair and they had cast a beautiful big image.  Mine sounded like cardboard.

Not being much of a believer in speaker break-in, I did decide to go that route.  I had been in contact with their designer, John Bau and while he generally very scientific, he did tell me they needed a break in period.   

I had an audio generator and SPL meter on hand and did run multiple frequency sweeps.  There were multiple "holes" where the output fell by several decibels.   Also bass output was weak.

I had two weeks in which to return them, so I figured "why not give them a workout?"  I put them in my basement and had them playing music for 72 hours.  I never went down to listen to them, I didn't want to break in my ears by growing to become familiar with the sound.  I wanted to listen to them right out of the box and then not again until they had 72 hours on them.

I brought them back up and positioned them exactly as I had them before.  Played the same music.   I couldn't believe my ears, they were tremendously improved.  Big, open, natural sound.  A joy to listen to.  Ran my frequency sweeps again and noted several differences, the big multiple dB drop around 100Hz was totally gone.  Bass output was significantly higher. 

To this day I do not understand how the sound changed so much.  I've had other speakers which haven't changed at all after a break-in period. 

John Bau worked on the design of the TC-60 for about 5 years.  Tweaking every aspect of it and measuring again and again.  Each driver set is matched. 

It doesn't play that well at loud volumes, but when set up properly and played at moderate to moderately-loud volume, it creates beautiful sound, with a very wide and deep soundstage, if a bit rolled off on the highest frequencies. 

Stereophile gave them a very positive review back in the 1990s, writing, "the soundstage thrown by the Spicas on this atmospheric track was huge, as in occupying a huge space between and behind the speakers, as in inducing a huge goosebump rush in moi, the listener ... Every audio reviewer lives for the moment when he or she hears true high-end sound quality emanating from affordable components. Which is why I got excited by the Spica TC-60. At $800/pair (plus $250 for the excellent stands), these speakers produce a sound that is much better than anyone with only so much to spend has any right to expect. "  They had them listed on their Recommended Speaker list for a while.

[77SunsetStrip]

Owned a pair of TC-60s since about 2006.  Found the midrange, particularly vocals, to be very natural.  Highs clean but a bit reserved.  Paired with subwoofer the only way to get sufficient bass.  There was a transition point in volume where they came alive, as if flipping a switch, and would fill the room with great sound.  Below that point sound was good, but one dimensional.  However, never thought the sound was lifeless without dynamics.  Anybody that heard the speakers wanted to know where they could get a pair.

During the lockdowns of 2020 upgraded the crossovers with good quality components, duplicating the John Bau design with a small tweak to increase the tweeter output.  The original crossovers were on a double sided board with heavy and wide paths, different than the picture shared by Hobbs.  After the upgrades separation of notes clearly improved.  Vocals better, able to hear small details previously just not audible.  The final icing was to raise the back of the speaker about 1/2 inch, tilting forward a little.  The high end simply sparkled.

In XSim the original circuit with my small tweak showed a frequency response +/- 2dB from 100 Hz to 20KHz.  Of course, XSim only works with component values and speaker parameters, not considering quality.  In room measurement with REW showed +/- 3dB from 200 Hz to 16KHz.  Just for fun tried an 8 component crossover in XSim.  Virtually the same FR as the original John Bau design with tweeter polarity reversed. 

No doubt better quality components make an audible difference, even if an FR plot does not reveal any difference.  Eager to see the cost of Danny's 6 component crossover design.  Might have to start another project.

[Hobbsmeerkat]

Cost of parts for this exact build was $563
Cost for a more typical upgrade kit, without the Miflex, and a erse/solen cap in the bass circuit is $410
That includes the crossover parts, tube connectors, wire heat shrink, solder and NoRez.

[ksypolt]

Hello, I would like information regarding this kit when you get it ready for sale. Thank you!

Kevin Sypolt
3919 Coldwater Drive
Rocklin, CA 95765

ksypolt@starstream.net

[adminRH]

Kevin it would be wise to edit out your personal information from previous post.
Thanks
AdminRH

[Tom Bombadil]

Paired with subwoofer the only way to get sufficient bass. 

During the lockdowns of 2020 upgraded the crossovers with good quality components, duplicating the John Bau design with a small tweak to increase the tweeter output.  The original crossovers were on a double sided board with heavy and wide paths,

I communicated with John Bau a few years ago.  He recommended upgrading the crossovers with newer, better quality components.  He felt all of his values were correct, but had to use less expensive components to hit his price point.  Also he acknowledged they would be old & tired parts now. 

As I wrote earlier, he spent years tweaking this design.  He was an early proponent of using test equipment to measure and model, he went into the test equipment business after leaving Spica.  His front baffle was the result of a long effort to measure different materials, thicknesses, and the exact cutouts in it to maximize imaging. 

I have always found the bass extension to be pretty decent.  My own measurements were very close to what Stereophile found in their lab, down -6dB at 40Hz, about -10dB at 32Hz.  Really strong bass down to around 45-48Hz.  His primary goal was to retain the imaging of his famous TC-50 while extending the bass.   He felt he achieved this. 

The drivers were an off-the-shelf Vifa which cost around $25 back then, and a customized Peerless 6.5" which cost him around $30-$40 each.  After Parasound purchased Spica and then shelved the line, they sold off all of the remaining mid-woofers to a company in Asia.   You can't get a replacement nowadays, there isn't even a close recommendation.  Bau felt that substituting anything else would radically change the sound.  He actually kept some of them and sold them on eBay for several years.  If you blow the mid-woofer, he recommended purchasing another TC-60 and hope that you get one which pairs with your other speaker.  They were custom matched in pairs. 

Sensible Sound also published a formal review of the TC-60:
"...if you like an immense and natural soundstage with 3D imaging, beautiful midrange reproduction and eerily real ambience, I strongly suggest you check out the TC-60s ...  Very highly recommended"

There's a very good webpage for Spica speakers
https://spicaspeakers.com/

[77SunsetStrip]

After a while on other projects, recently circled back to TC-60 Mods.  My duplication of the original crossover a while back with higher quality parts made a positive difference.  However, have not been able to get Danny's significant mods out of my head.  Was a 25+ year old speaker representative of the original designers goals and performance.  Jon Bau recommended replacing the electrolytic caps after 15 years with good poly caps.  Was ferrofluid in Vifa tweeter still good?

Researched ferrofluid to learn pros and cons.  Checked the Vifa tweeters in my TC-60s.  Hardly any ferrofluid present.  Theil-Small parameters measured no where near the Vifa spec sheet.  Could that be why my TC-60 as stock crossover FR measurements showed a high end drop off above 10K?  Better quality crossover parts, particularly a 0.01uF bypass in the tweeter circuit moved the drop off out to above 16K.  I described the change as sparkle in the highs.   

A week ago cleaned out old ferrofluid and replaced with new.  Theil-Small parameters measured close to the Vifa spec sheet.  Have not measured FR yet, only listened.  Now I would describe the highs as silky, clean, smooth. Previous sparkle gets your attention, but silky, clean and smooth is better.  Have to wonder if the TC-60s Danny/Hobbs modified need a ferrofluid refresh?   

[tull skull]

I have not listened to Danny's video yet but I am pleased that he included in the title the term "Legend". Yet it is not the speaker itself that deserves the accolade. John Bau did speakers like no others. They were soaked in solid design and innovation. Unique, off the beaten path innovation.

 If you got the ho-hums from listening to his speakers then it's a good indicator that something is not right. And I ain't talkin' bout the design. It may be speaker damage or your set up but I just wish there could be more respect given for what some accomplished with what they had to work with. That goes for driver tech and measurement gear.

Never been a Parasound fan unfairly because they scrapped the speakers but honestly there was no way they could afford to go to the trouble that John required for his designs. They also lost their enclosure maker and no, China couldn't pull off a cheap copy.

John measured each resistor for close tolerance pairing. Parasound's copy would have almost doubled the price.

I suggest you look up interviews and see if you get an appreciation for his design thoughts. I remember an incredible breakdown from International Audio Review on the TC-50 but I am not sure if it is online. Today with how far tech has come it is so easy to find the weaknesses of past designs and dismiss but perhaps stop and realize that when you unscrew a woofer or tweeter from a speaker that you just my be peering into the design of a giant. A legend perhaps.

77 Sunset, that is a very interesting and also very intriguing observation you discovered with the ferro fluid. Excellent detective work!

[Hobbsmeerkat]

It probably did, considering the TC60s sent to us had a rolled off top end also, but it wasn't something we looked into.

[77SunsetStrip]

Here are some REW measurements of Spica TC-60 in stock condition, after crossover component upgrades, after tweeter ferrofluid refresh.  REW measurements taken in my listening room under as identical conditions possible.  Not an REW expert, so welcome thoughts or advice from more experienced users.  For all graphs 4ms window, 1/3 smoothing.




TC60 in stock condition.  High end starts dropping above 4K.




October 2021 TC60 after crossover mods. Duplicated original crossover with higher quality parts.  Changed 1 resistor value to increase tweeter output.




April 2022 after tweeter ferrofluid refresh.  Might need to go back to the stock resistor value previously changed.  Although with seasoned citizen ears, the high end sounds pretty good.   

[Tom Bombadil]

Here's the TC-60 frequency response as measured by Stereophile way back in 1994

[Tom Bombadil]

I should have included the link to all of the TC-60 measurements taken by Stereophile :

https://www.stereophile.com/content/spica-tc-60-loudspeaker-measurements

"In my listening room (fig.6), the result of this excellent on-axis performance but more idiosyncratic off-axis behavior was a superbly flat balance throughout the audioband. With the exception of the presence region, where the contribution of the above-axis response resulted in a slight lack of energy in the speaker's room sound, the Spica's 1/3-octave response met superb ±0.7dB limits from the lower midrange up to 10kHz. Few speakers at any price have done this well in my listening room. That the $800 Spica can do it is testament to the talent of its designer. "

[Randy]

I had two pair at different times of Spica TC - 50s, predecessors to the model being discussed here,  back in the 80s.  The soundstage they threw was uncanny. Never heard speakers like them where sound seemed to emanate beyond, left and right, and above the physical units. They were noted for that illusion. I must have moved on to Magnepans after them, but was temped a few times later to buy another pair. Never did, however. Legendary speakers, indeed, despite their weak points.

[77SunsetStrip]

First, personal curiosity regarding the TC-60 owner reasons for sending to Danny, did they perform the suggested mods, and do they like the results. 

My crossover mods and Ferrofluid refresh definitely made a difference.  Did those changes improve upon the original or just return a 25+ year old speaker to original performance?  Prior to my mods would never have described the TC-60 as Hobbs did.  Although, understand with my after mods listening experience the prior sound of my TC-60s could be described as a little dull.  However, never unlistenable.  The TC-60s always produced a soundstage unlike any of the other dozen or so speakers owned. 

Reading a John Bau interview where he mentioned replacing the TC-60 electrolytic caps with poly caps was the initial impetus for considering crossover mod efforts.  Then, discovering Danny's videos inspired me to just jump in.  The process with the TC-60 was baby steps, one change at a time on 1 speaker.  From the first component change the difference over the original undeniable.  With all the changes, my ears say they are better than the original condition.  Soundstage is more three dimensional, with no sense of music coming from two boxes.  Still, would not call the original TC-60 condition unlistenable. 

[Hobbsmeerkat]

First, personal curiosity regarding the TC-60 owner reasons for sending to Danny, did they perform the suggested mods, and do they like the results. 

My crossover mods and Ferrofluid refresh definitely made a difference.  Did those changes improve upon the original or just return a 25+ year old speaker to original performance?  Prior to my mods would never have described the TC-60 as Hobbs did.  Although, understand with my after mods listening experience the prior sound of my TC-60s could be described as a little dull.  However, never unlistenable.  The TC-60s always produced a soundstage unlike any of the other dozen or so speakers owned. 

Reading a John Bau interview where he mentioned replacing the TC-60 electrolytic caps with poly caps was the initial impetus for considering crossover mod efforts.  Then, discovering Danny's videos inspired me to just jump in.  The process with the TC-60 was baby steps, one change at a time on 1 speaker.  From the first component change the difference over the original undeniable.  With all the changes, my ears say they are better than the original condition.  Soundstage is more three dimensional, with no sense of music coming from two boxes.  Still, would not call the original TC-60 condition unlistenable.

The owner bought the TC60 after giving away his old system to a friend. But they didn't live up to his expectations, and sent them to us to design an upgrade for them, and have me install them.

They sounded like a totally different speaker after the upgrade. Worlds ahead of their original configuration.

I tried reaching out to them to see what they thought of the speaker after having it on hand for a while, but I never hear back from them.
I may need to reach back out to them again, by phone if necessary, as I'm still curious about their thoughts.

I may have been a bit harsh in my initial listening impressions, but I'd still call them dull. Cuz in my system, that's exactly how they sounded, especially compared to the other speakers I normally use in my system. After the upgrade they came much closer to the performance level I know its capable of.

[Mitsuman]

Just to add my $.02, my nephew has a pair and they were original and unmolested when he picked them up. I remember hearing them and thinking they sounded flat, kinda muddy, with no sizzle on the top end and average imaging.

Some time after me expressing my opinion on their sound, he had them upgraded but I honestly don't know if he just had them re-capped or to what extent they were upgraded. Since they were upgraded, they do sound like totally different speakers. Imaging is very good, and the music is all "there" now with no muddiness. The upgraded sound is night and day from how they sounded when he first picked them up. They are very pleasant to listen to, and I can see why folks would enjoy them. They still aren't really my cup of tea, but the improvement in sound that can be had over stock is not subtle.

[77SunsetStrip]

Hobbs, no need to amend your listening impressions of the TC-60s before mods.  You heard what you heard, no argument intended.  The rest or your system, or mine, certainly contributes to the overall listening experience.  After my mod experience, in total agreement the stock configuration can be improved significantly.  In my case, there was not a specific audible shortcoming I heard that required attention.  Really started as preventative maintenance to get rid of electrolytic caps.  Turned into an experiment to discover what could be possible.  A very rewarding experience.

By the way, veered off course a couple times with ideas for circuit adjustments that did not end well.  Every change was not automatically positive just cause I did it.

Keep up the good work.  Definitely interested in any additional customer feedback.