Wirrunna

Here is the T2A as mentioned earlier. I have always understood that the autoformer is just a simple attenuator in the AK3.

200v caps will be fine, but what kind of Arizona caps are they ? Paper & Foil ? Polyester, Metalized etc.

https://community.klipsch.com/index.php?/topic/200515-my-first-k-horns/&do=findComment&comment=2627740 This is excellent advice. I have 1990 K-Horns and a few years ago started down the rabbit hole of modifications. The first thing I did was to have a good look at the AK-3 balancing network and the cabling. The Monster Cable from the AK-3 to the speakers had gone a lovely green in sections and the clear insulation had gone sticky. Also, there was no terminal strip connector, the cables were soldered directly to terminal pins on the crossover board. After some research on this forum I ordered a cap replacement set from Bob Crites as well as a terminal strip. I measured the caps after I removed them from the board, and while a couple of them were close in value their ESR was up around 5 ohms. Others were way off the nominated value. The cabling in the woofer was OK but the caps were off spec. So, I recommend that you get the K-Horns installed and playing, and inspect the crossover boards and internal wiring in the top hat. Then investigate the JEM Performance cap replacement kit, for the AK-2 or AK-3, the only difference I am aware of between the AK-2 and AK-3 is the AK-2 has 140uf (2 x 70uf) in the woofer circuit and the AK-3 has 100uf (2 x 50uf). Scroll down this page to the AK-2 AK-3 diagrams. https://community.klipsch.com/index.php?/topic/113804-klipsch-crossovers/ As Tom said in his post, listen to them for a month or two. Different crossovers won't make as much difference as moving furniture around in your room or putting a thick rug on the floor in front of the speakers. Certainly before you try anything other than the cap refresh, get yourself a miniDSP UMIK measurement microphone and teach yourself how to measure the speakers with REW.

Read all about it here -

TexDrone, I found that the miniDSP added noise that did not increase when the volume control on the preamp was turned up. After a bit of googling I found a suggestion to use an L-Pad to reduce the speaker output which included the noise and that in turn required an increase in gain to bring the level back up to where it would be without the L-Pad, but the noise stayed reduced. http://www.sengpielaudio.com/calculator-Lpad.htm shows how. My project is https://community.klipsch.com/index.php?/topic/195572-bc-dcx464-as-the-mid-hi-drivers-for-a-k-horn/

TexDrone, I tri-amped my K-Horns with a miniDSP 2X4HD for each channel. I had noise in the mid and hi speakers and made L-Pads to drop the sensitivity of the speakers. The noise is generated by the DSP. Chris, I have often wondered if on the DSP I could up the gain at the input by say 3db or even 6db and then drop the gain on the DSP outputs by a corresponding 3 or 6 db on the theory that if the low level signal from the pre-amp is down near the noise floor of the DSP then by boosting the signal level as it enters the DSP the noise added by the DSP will also be attenuated when the gain is cut as the signal leaves the DSP. I have also noticed that noise is far more evident when a USB cable is attached to the miniDSP.

I recommend a polyswitch - https://www.parts-express.com/electronic-parts/Fuses-Fuse-Holders/polyswitch-resettable-fuses At around 60c , buy a few pairs in increasing amperage, put the lowest in circuit and try it, if it cuts out too often then move up to the next value. Auto bulbs are going LED, which don't work as well due to much lower wattage. Edit: Good description of how they work here - https://www.jaycar.com.au/rxe075-ptc-fuses-speaker-protection/p/RN3460

Why the 5" length ? I went with the 4" as Claude specified when I swapped the Dayton into my Super Heresy back on page 14 of this thread.

erez, the ALK Extreme Slope networks are expensive to build. I know, as I built some a few years ago - https://www.stereo.net.au/forums/topic/118361-k-horn-crossovers-from-ak-3-to-universal-to-es/ and have recently replaced them with an active system using miniDSP 2X4HD - I spent a lot less on the miniDSP 2X4HD and Audiophonics Hypex N-Core amps than I did on caps for the ES networks. ALK pulled the DIY instructions for his networks some time ago.

Here is the T2A spec sheet

How did your search go ? Here https://community.klipsch.com/index.php?/topic/122257-klipschorns-can-i-sealclose-the-back-w-plywood-or-smth-else-instead-of-adding-walls-to-the-room-do-not-kill-me-for-asking/&do=findComment&comment=1355838 is Don Davis' simple solution attached to the mounting boards on the grill with 4 screws.

Madman, A good starting point is https://www.parts-express.com/Loudspeaker-Design-Cookbook-7th-Edition-Book-500-035 and here is a primer on crossovers - https://sound-au.com/lr-passive.htm

Here are two more threads about ALK Universal crossovers, this one which includes changes to crossover at 4500Hz if you are using an upgraded tweeter . and this one shows how to utilise an AK3 woofer section with the Universal

What driver did you use for the measurement ? The thread is a really good read, lot of good information.

Apologies in advance if this is the wrong thread - I'm pretty sure that this https://community.klipsch.com/index.php?/topic/42953-false-corners-screwed-into-k-horns/showed Khorns being in false corner cradles but it appears that Deang has deleted all the images ! In fact this is not the first thread I've found that Dean has deleted text and pics, what's going on ?

For completeness - https://community.klipsch.com/index.php?/topic/105239-another-tractrix-horn-design-program/ Also, the Eliptrac is FC310Hz - https://community.klipsch.com/index.php?/topic/122814-round-tractrix/&do=findComment&comment=1358020

Is the K400/401 a CD horn ? It is a bit hazy now, but I seem to remember a wider coverage when I swapped to the Eliptrac.

Thoughts ? Eliptrac horns have been around for a while now. I believe Dave Harris is still making the kits although his web site has been gone for a while. First, replacing a K400/401 with an Eliptrac is a modification and will alter the sound of a Klipschorn. Second, as far as I can tell most people that use Eliptrac horns no longer use the K55 drivers. Third, as they are a kit and take quite a bit of effort to build, I suspect there is a fair bit of self fulfilling expectations in the evaluation of their performance. Having said that, I built a set for my 1990 KHorns, initially using Bob Crites A55G drivers with an Al Klappenberger designed Extreme Slope 400/4500 crossover and Bob Crites DE110 tweeters. I found the modified KHorns lost the harshness that was evident on some orchestral music and completely eliminated listener fatigue. The sound was smoother and more open with a more detailed soundstage. I then had an opportunity to purchase a second hand pair of B&C DCX464 co-axial drivers locally (a unique opportunity in Australia where most HiFi components are imported with associated freight, customs duties and delays due to shipping). Attempts at passive crossovers were disappointing at best so I went active with very pleasing results. I don't know how much you have read, so I will list a few links that I have bookmarked - https://community.klipsch.com/index.php?/topic/122814-round-tractrix/ https://community.klipsch.com/index.php?/topic/144700-eliptrac-400-kit-finishing-update/&ct=1557489906 https://community.klipsch.com/index.php?/topic/124081-testing-the-faital-pro-hf200-driver-on-the-eliptrac400/&ct=1612245896

Dave, I have never seen a precision L-Pad. One of the problems in calculating L-Pad values is that a speaker's impedance varies non-linearly with frequency, and the manufacturer's publish a "nominated" impedance. One way of getting there would be to measure the system response, determine the tweeter attenuation needed, refer to the manufacturer's impedance curve for the impedance at the passband and use https://sound-au.com/articles/l-pad-calc.htm to calculate the values needed.

You could try https://www.madisoundspeakerstore.com/yung-binding-posts/posts-hg-postr-binding-post-red/ Looks like it bolts through a panel and accepts banana plugs. I tri-amped K-Horns and just used a terminal block in the top hat.

Chris, I have added the remaining measurements including the EQ'd but no delay in the miniDSP. Now, a question - how flat should the phase be ? Certainly the first music I played back in early January when I got this flatish phase cross over working was a revelation. There were some tracks that you could swear it was a mono system and the speaker was disguised as a slow combustion wood fire sitting near the wall in the middle a long way from the two corner cupboards with Klipsch labels. While other tracks had instruments coming from further out than the corner cupboards. And Dark Side of the Moon when the alarm clocks went off frightened everyone. Is there some acknowledged measurement for phase, e.g. + - 30 degrees from 200 to 10,000 ?

Using REW and rePHASE to create a flat phase crossover for miniDSP 2X4 HD. Section 3 - Measuring and setting Gain and Delays in miniDSP 2X4 HD Section 3 - Configuring the miniDSP.pdf

Using REW and rePHASE to create a flat phase crossover for miniDSP 2X4 HD. Part 2b - measurements. of the reworked miniDSP configs. Section 2b - rePhase for xovers and flatten phase - Oct rev 1.pdf

Using REW and rePHASE to create a flat phase crossover for miniDSP 2X4 HD. rePhase screenshots updated pdf Section 2a - rePhase for xovers and flatten phase - Oct rev 1.pdf

Chris, I agree with what you said above which is why I have spent a day or two going back over the rough procedures that I wrote down to dial in my DCX464 in my K-Horns with a miniDSP and have assembled REW measurements, EQ settings and the resulting REW measurement and RePhase settings and the resulting REW measurements for each driver. Today I intend to set up the measurement microphone again, get into the miniDSP and turn off delays and level matching and run some REW measurements to show before and after plots, spectrographs and GD. I have expanded the resulting document and will break it into into a series of .pdf files rather than a great long thread full of REW plots and screen captures. I suspect that a lot of members of the forum are daunted by the technical challenge of adding a DSP and a couple of amplifiers to go "active". I have the motor board from my K-Horn's top hats, complete with original K401 / K55M and K77M, it is only 4 screws to swap this from the DCX464 / Eliptrac motorboard. So I'm thinking hard that it may be worthwhile doing an AK3 to Active project some time and document it. The resulting REW measurements and EQ, RePhase tweaking and miniDSP settings from a K-Horn would be good starting point for a La Scala or Belle .