Archive | Home Audio RSS feed for this section

DIY Klipsch Heresy Baffle Seal

10 Sep

In light of the recent coverage on Klipsch Heresy capacitor replacement, I’d like to follow up with an even easier upgrade for your compact, sealed wonders that costs about $5 and takes less than 5 minutes to install.

Let’s first look back at the term “sealed.” The Heresy got its name because it was such a radical departure from the previous designs of Paul Klipsch, which revolved around large, ported cabinets, 15″ woofers and folded bass horns to improve low frequency response. With the Heresy, Klipsch broke many of his own design principles, achieving quality, full-range sound from a relatively small, sealed enclosure, housing a front-loaded 12″ woofer.

Now I can’t speak for the second and third generations of Heresy cabinets, but the original boxes have a removable rear panel, secured with eight Philips head wood screws. The panel simply butts up against a 3/4″ strip of wood around the perimeter of the box interior. While this does secure nicely when screwed down tightly, I’m skeptical of the wood on wood air tight-ness–an important detail for a sealed speaker design to adequately reproduce low frequencies.

Here’s the part where you go to the local hardware store and pick up some foam weatherstripping like you would use to eliminate drafts from door jams and window frames. You’ll need at approximately 136 linear inches of the stuff (11′ 4″) to seal one pair of speakers. It comes in several different widths. I chose the 1/4″ variety, which in reality is closer to 1/3″ wide. If you wanted to really go for overkill, you could spring for the 1/2″ or 3/4″, but the wider you buy, the more you should plan to spend. It does spread out in width a bit when compressed, so I feel the 1/4″ stuff does the trick. It also fits nicely between the edge of the cabinet and the existing screw holes.

Application, just pull the tape off the adhesive backing, apply a strip of the weatherstripping around the perimeter of the cabinet and replace the rear panel.

Don’t expect a night and day difference, but those who know the Heresy will welcome any help in the LF department. The expansive properties of the foam also apply pressure against the back panel, helping keep the screws tight and eliminating possible vibrations and rattles in the rear baffle.

Just another step to ensure your Klipsch Heresy speakers are operating at their highest potential for many more hours of listening pleasure.

Klipsch Heresy “Type E” Capacitor Replacement

8 Sep

Eight years ago I picked up a beautiful set of Klipsch Heresy speakers.  My dad used to sell hi-fi in the 80s and one day an old friend and former customer called him up to say he was moving to Florida and letting go of his stereo (apparently they don’t allow nice stereos there).  We went over to his house and auditioned what he had, which included this first generation Klipsch Heresy pair.  After a brief listening session I couldn’t help but take the speakers home with me.

There are some fairly heated debates among hi-fi buffs over whether or not the Heresys are worth a damn. Some listeners hate them, some love them.   I happen to be in the latter camp, so I’ve toted them along from place to place, most recently in my cross-country move to Montana.  They always manage to find their place in my primary listening system, driven by a Kenwood M2A at 220 watts/ch.

With a manufacture date of sometime in 1980, these particular speakers are now 33 years old.  They have been well cared for throughout their lives.  The cabinets are in excellent condition and all the drivers are original, with the exception of diaphragm replacements in both K-77 tweeters.  I had one die on me a couple years ago and opted to replace the HF diaphragms in both speakers for sonic consistency, with genuine Klipsch parts, of course.

Even when well cared for and used properly, the capacitors in the crossover network are bound to fail to some extent over time.  The “Type E” crossover network found in Klipsch Heresy speakers up to 1982 consists of two capacitors, two transformers and a wiring block.  All capacitors have a lifespan.  While in a few rare instances they die suddenly when overdriven, they usually tend to drift off spec with age.  Of course, as the caps drift off spec, so does the sonic character of your speakers.

Mine seemed to sound fine, but I figured they deserved some maintenance after several years of faithful service.  I’m a bit of a novice when it comes to replacement of electronic parts such as this, so I didn’t feel comfortable sourcing my own capacitors.  Luckily, a gentleman by the name of Bob Crites has replacement kits available on his website.  Within a few days I had four caps and a wiring diagram on my doorstep.  Time for some fun.


It’s pretty easy to remove the crossover, or “balancing network,” as Klipsch calls it.  Loosen the screws on the wiring block for the three pair of driver leads and the rear panel input, remove two screws for board the x-over components are mounted to, and the whole network comes right out.


Isn’t that steel label plate cool?  The two old capacitors are those oil-can looking things, located top center-ish on the board.  Note the rust starting to build up on the outside–yeah, pretty old.  Just clip the leads, unscrew them from the mounting plate and you’re ready to install the new caps.  Along with new Sonicap capacitors (rated at twice the voltage of the original caps), Bob also includes mounting blocks and zip ties, leaving you with everything you need to complete the task minus some solder and an iron.  Mount the new caps, consult Bob’s included wiring diagram (or take detailed pictures of the crossover before you remove anything), sling some solder and there you have it.


It took less than an hour to pull and update and reinstall the crossovers for both speakers.  Not a bad Saturday project–plenty of time left over for a bike ride, a drink or an extended listening session with your refreshed speakers–or all of the above.

Let me take a step back and say that I had no proof my old capacitors were “bad.”  Again, bad caps can continue to work, just not to their original specifications, so even though my speakers seemed fine, they may very well have strayed from their original sonic signature.  My personal stash of electronic testing tools is limited to a couple of multi-meters, so there was no scoping to be had.  However, I do own a cheap Dayton EMM-6 measurement microphone, a USB audio interface and a computer.

Before I even unhooked the speakers for their surgery, I downloaded a trial version of FuzzMeasure and set up a little measurement rig.


While the angle of the photo is a little misleading, I placed the microphone so its capsule was one foot off the grill, pointing about halfway between the tweeter and woofer–pretty much right at the K-55 midrange driver Klipsch lovingly named the “squaker.”  I put some tape on the floor to make sure got things back in the same place for my post-installation measurement.  I measured the speaker, swapped the caps as described above, then measured again.  Below are the two measurements overlayed.


As you can see the response stayed more or less the same.  A slight gain in HF output and a little change in the transition zone between the LF and MF drivers.  Of course these measurements aren’t perfect, but it is nice to have a visual representation.  But do they actually “sound” better?

Verdict: Experiments like this are often hard to judge.  You’ll read all sorts of ambiguous adjectives when looking at others’ accounts of capacitor replacement.  “The soundstage was vastly improved.”  “A sparkle was restored that I hadn’t heard in years.” “I discovered a 4th dimension after replacement.”  Yadda, yadda, yadda.  While I cannot say right off the bat this “upgrade” drastically changed my speakers’ sound, I can say the project was greatly rewarding.  These speakers have been with me for many years and have never let me down.  Day after day, night after night they enable me to listen to music.  If nothing else, this endeavour is an insurance policy that our relationship will last many years more.

Infinity Sterling SS 2003 Bookshelf Speakers

7 Oct

Yesterday I picked up some Infinity Sterling (model SS 2003) bookshelf speakers on Craigslist for $10. They had the rotten foam surrounds typical of nearly all Infinity speakers their age, so would obviously need some work there. The cabinets are quite heavy and very solid, but I don’t really want to pay for an overpriced woofer refoam kit online, nor do I really want to put a bunch of time into this project (I’ve already got plenty of others on the back-burner) but I think there may be another solution.


It just so happens I had a couple of Dayton Audio RS255-8 8″ woofers I picked up on Parts Express a few years ago for a project that never came to fruition. That was money spent long ago, so in my mind they’re free woofers in this situation. The SS 2003 has a crossover point of 3khz, and these woofers are only “usable” to 2khz, but I’ll let my ears decide if that’s a big issue. Again, woofers I already had sitting around.


The Daytons dropped right in with no cabinet modification required. They’re slightly bigger regarding basket diameter, so they sit on top of the baffle as apposed the the inset bevel of the original drivers, but a little mounting foam and a few screws later, they were seated nicely.

The woofers are pretty darn inefficient at 86.2 db versus the original Sterling system efficiency of 90 db, so the tweeter outruns the woofer a little bit, but its a pretty good sounding set of boxes for at total investment of $10 and 15 minutes of repair time. Of course the perfectionist in me always wants to restore speakers to their original condition, but there’s something to be said with working with what you already have on hand.

At the end of the day, it’s nice to have saved another set of speakers from the dump.


Infinity Qb EMIT Tweeter Repair

12 Apr

Lots and lots of shows at the Gillioz these days, but I’m still finding time to take on a few personal projects here and there.  When I saw a set of Infinity Qb speakers on Craigslist for $50 I couldn’t pass them up.  As seen in an earlier post, I restored a set of Infinity RS5b speakers and fell in love with their sound.  The Qbs are essentially the grandparents of the RS5b.

However when I arrived to buy the speakers, a quick visual inspection (and subsequent listening) revealed both EMIT planar tweeters where non-functional.  You could easily see a tear in each of the drivers, so I talked the guy in to letting me take them home for half his asking price, which seemed fair for both of us as the woofers and mids were working just fine.  If nothing else I could always part the speakers out, though I really hate promoting that practice.

I did a little research online and read about a guy who fixed some EMIT tweeters with this conductive paint used for repair automobile rear-window defrosters.  My local auto parts supplier had some for about $10 a bottle.  An additional trip to Hobby Lobby to find the smallest paint brush I could (the one included with the paint was too wide) and I had everything I needed to tackle the project.

The whole task was a little daunting, as the line I had to paint to restore the circuit was so very small, but it’s hard to break a tweeter that’s already broken so I just dove right in.  I filled in the missing gaps and let the tweeters sit overnight before running audio through them (though I did confirm I had completed the circuit with a volt/ohm meter).

This slideshow requires JavaScript.

Low and behold, it actually worked.  I’m still in disbelief, but both tweeters work and sound just as they should.  One of the two tweeters quit working after a few seconds, but a second coat of conductive paint resolved the issue.  We’ll see how they hold up after additional hours of play time, but I’m really happy about how things turned out.

Now I’ve got a (second) cool set of vintage Infinity speakers and am only out about $37.50.  Let the listening commence!

Infinity RS5b Woofer Refoam

21 Jul

I recently acquired some Infinity RS5b speakers in nearly perfect condition.  However, the foam surrounds on the woofers would crumble if you so much as looked at the speakers, but that’s a fix I can handle, and this seemed like a project worthy of my time.

Sure enough, new surrounds were easily found online and with only a few hours of work, the speakers were restored to new.

In my excitement to get these things in listenable condition, I forgot to take “before” pictures, so you’ll just have just take my word for it.

Klipsch K-77 Diaphragm Replacement

2 May

Last week in a momentary lapse of judgement, I fried the K-77 tweeters in my Klipsch Herseys.  I don’t really want go into details, as the experience was quite traumatizing, but what do you know, a quick call to Klipsch in Hope, Arkansas had two diaphragm kits on my doorstep in only a few days.

The “diaphragm kit” that Klipsch offers is different from the bare diaphragms you’ll find online in that they come pre-mounted on the little cup that holds the diaphragm between the magnet and the horn lens.  If I had ordered the bare diaphragm, I would have had to mess with soldering those tiny lead wires on to the driver’s terminals–an operation I’m willing to perform, but is always a risky process.

Klipsch didn’t include any directions with the diaphragm kits, but there is enough information online to answer most any question that could come up.  I did get a little stumped when I had trouble removed the old diaphragm cup from the horn lens, but a call to Klipsch customer support informed me of the “whack the horn with a screwdriver handle to pop it off” trick.  Worked like a charm.  My customer service rep said he’d talk to the guys in parts about including directions with the diaphragm kits in the future.

Here are a few pics from the adventure.  I love the old school badges on the Klipsch Type E crossover network.  Hmmm…I wonder what condition those capacitors are in…

This slideshow requires JavaScript.

After 20 minutes of listening to my Heresys with fresh tweeter diaphragms, I realized how much I had missed these speakers over the six day period they were out of commission–a truly classic speaker.

Side note: A cool factoid I found out while researching the K-77 tweeter is that the Electro Voice ST-350 tweeters use the same diaphragm.  I already knew this was true for the EV T-35, as it looks nearly identical to a Klipsch K-77.

Carver “Premiere” AV-705x

25 Apr

I just scored this beauty from a guy on craigslist.  Rated for 125 watts x 5 with a THD <0.03%, I’m quite excited to give this piece a listen.  Apparently one of the channels is not functioning.  However, notice the five distinct heat sinks visible on the top of the unit.  This amp is a modular design, with a common power supply and capacitors supplying five individual channel cards.  Hopefully I can get the bad card repaired or replaced, but if not, it’s still going to make a great four channel amplifier.