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[howman7]

Hello All,

I recently purchased a pair of original Heresy's to be paired with a Yamaha DSP A1. I know - tube, tube, tube! I just do not have that in my budget. The amp is a very solid piece of equipment though.

When I bought the speakers, the seller made no mention of "re-capping" or anything else that may or may not be an issue with the speakers. How can I guage the performance of these speakers to the original specs?

Thanks for the anticipated assistance as this is my 1st post.

H

[Islander]

How old are your Heresies? They might well benefit from new caps in the crossovers, but if they sound fine to you as they are, that's an update that you can do at your convenience. It's not usually an issue as such. New caps are not expensive and are easy to install. The sound will be improved, but it's not a day and night difference.

Also, welcome to the forum!

[howman7]

Thanks for the response.

As far as I can tell they are first gen. Model HOO and serial number 8546449. They are beautiful speakers. I just feel from what I have read, the highs could be a little brighter for this speaker. Like high hat predominate? Is there a way for me to get in there with a meter and measure impedance for each the tweeter, mid horn and woofer?

H

[JohnA]

Those are 1985 models, nicknamed Heresy 1.5, here, because it has an HII squawker. They are at least 4th generation (Model H, H-700, Heresy (through ~1982), yours).

It is difficult to measure capacitors for quality. It requires unusual test gear. If you can find a really good electronics tech, ask if he can test the ESR (Equivalent Series Resistance) of your caps. Testing the drivers is straightforward with a multimeter. Disconnect the leads from the crossover and measure the resistance. However, if the driver in question is putting out clean sound, that's proof enough.

That said, normal Heresies are bright. if yours are not, you might consider replacing the caps. At 24 years old, they are prime candidates for replacement, especially if they haven't been used regularly over the years.

[Islander]

Is there a way for me to get in there with a meter and measure impedance for each the tweeter, mid horn and woofer?

It's easy to measure resistance with an ohmmeter, but I think measuring impedance is a little different. In one example I can recall, a speaker with nominal 8 ohms impedance shows 11 ohms resistance.

The meter will show you if the driver has continuity, if that's all you need to know, but if it's making sound, it has continuity.

[Q-Man]

I think that John was talking about measuring the resistance of the individual drivers. An 8 ohm driver will measure about 6 ohms, and a 16 ohm driver will measure about 11 ohms. A combination of drivers and networks in a speaker could measure anything. You would have to ask the manufacture what the dc resistance of the whole speaker should measure.

I bought a pair of Altec 288-16K midrange drivers a while back when I was doing some experimenting. Before I tried them I measured the resistance. One measured 11 ohms and the other 6 ohms. This told me that someone replaced the diaphragm in the 6 ohm one with a 8 ohm diaphragm. I opened it up and found an 8 ohm diaphragm. Did the seller know this? I don't know. I need to call Bill at Great Plains Audio and order a 16 ohm diaphragm, so I can sell them as a pair.

If I remember correctly, Trey once told me that the LaScala should measure around 3.4 ohms. I used this when I was buying LaScalas as a quick test.

[PrestonTom]

Congratulations on the Heresy cabinets.

My suggestion is don't bother trying to measure the caps. Simply go ahead and replace them. As mentioned above, the early to mid-80s cabinets have differences between them. So it is safest to simply pull out the old crossover and write down the cap values. If you need help then post a photo and we can guide you.

Once this is done, you can order decent replacements from Parts Express (or whoever) for about $20. If you want to go the extra step you can also "bypass" the caps (a second cap in parallel with 1-5% the value of the first cap). It is a simple enough job if you have a soldering gun.

Of course there are always more expensive alternatives. My own advice is that you spend some time on speaker placement etc. The cabinets are bass shy and will benefit when placed near "boundaries" (floor,wall, corner)

Good luck,

-Tom

[howman7]

Here are some photos that show the crossover.

Thanks for all the help.

Are there step by step instructions that outline this process?

Howard

[PrestonTom]

These are not step-by-step instructions, but enlist the aid of a friend and this will get you started.

1. Make sure sure you have the following drivers (there were some variations in these years/models)

Woofer: K-22

Mid: K-53

Tweeter: K-77

2. There are 3 caps you can replace, and others will recommend other brands (usually more expensive). I do not want to discuss which is the "preferred" brand since that discussion is not very interesting to me. I can not find a proper schematic. Perhaps someone could kindly post one. The other two pieces in the crossover are an autoformer (T2A) which adjusts the impedance/gain and an inductor (when in series is a low pass filter). These two devices are probably not worth replacing.

a. there is a 2 uF cap between the autoformer (T2A) tap & the tweeter (K-77)

b. there is another 2 uF cap before the autoformer (T2A)

c. There is a 33 uF cap across the woofer (K-22)

NOTE: If these are not the transducers in your cabinet or it does not have these three capacitors, then you need to tell us exactly what is inside.

One choice is to go to the Parts Express website and get the Solen metal polypropylene caps. For the 2 uF they cost about $3 per cap. The 33 uF cap is about $15. If you want to get fancy then you can "bypass" the caps by putting a second small cap in parallel with the first (about 1-5% of the uF value). For instance the Dayton film & foil cap of 0.10uF would be appropriate to bypass the 2 uF cpas with (and they only cost a couple of bucks each). If you want to change brands and the other brand only comes in 2.2uF or 30uF, that is close enough. So we are at about $20-25 per cabinet. However, you can always spend more....

All caps should be installed as before (either soldered or with a screw connection), all contacts should be cleaned and replace them exactly (do not reverse the polarities of the connections relative to the original wiring). You can attach the caps to the board with a dab of glue. If you are obsessive, then put a thin strip of weather stripping on the rear panel when you screw it back on. This seal will help to minimize air leaks. Some folks will also glue a board (1" by 2") to the inside of the back panel to stiffen it up a bit.

I shy away from using phrases like "the sound was now opened up" or the "veil was removed". I think you will find the sound to be a bit more balanced across the spectrum with a bit more energy in the highs. The difference will be noticeable but not earth shattering.

Good Luck,

-Tom