Markwart 605 XO cap values

[Basplin]

Hi everybody,
I am the newest addition to the ALTEC fan club with a purchase of a 605A I'm very excited about turning into an awesome mono speaker! I'm going to build the Markwart 605 XO and I have a question about cap values. It requires 3 caps - 4.7uf, 5uf, and 7uf. The options for 5 and 7 are limited in that there are only a few available that are affordable. I managed to find a 5uf Genteq/GE Film Oil cap, but the closest I could find for the 7uf is 6.8 - Obbligato Film Oil. Would using 6.8 be acceptable, or am I better off finding a 7? For most things, I would think 6.8 is fine, but I'm just not sure how close these tolerances on the MW XO need to be.

Crossover for reference: http://home.earthlink.net/~jmarkwart...605a_brev1.pdf

Thank you!

[Elitopus1]

Welcome to the hostboard!

For instance on my xover they called out for 6uf, 12uf, and 25uf caps. I couldn't find the 25uf so I bought the 24uf. When I tested them before install they tested at 25.2uf and 25.3uf. Good enough for me!

Some people want to hit the values exactly. I am one that is ok with the values being within the 3-5%.

I also tested each one of my caps and made sure each crossover was "even" from side to side with caps values.

I have also heard of people buying many more caps than they need, testing them, and then using the closest values.

If you search the hostboard there are at least a few recent threads on Markwart's xover. I also emailed Jeff with a few questions and he was very helpful.

Please post some pics when you are done!

Altec 604G Markwart xover (1st attempt)

Jeff Markwart's 604-8G crossover

[Basplin]

Welcome to the hostboard!

For instance on my xover they called out for 6uf, 12uf, and 25uf caps. I couldn't find the 25uf so I bought the 24uf. When I tested them before install they tested at 25.2uf and 25.3uf. Good enough for me!

Some people want to hit the values exactly. I am one that is ok with the values being within the 3-5%.

I also tested each one of my caps and made sure each crossover was "even" from side to side with caps values.

I have also heard of people buying many more caps than they need, testing them, and then using the closest values.

If you search the hostboard there are at least a few recent threads on Markwart's xover. I also emailed Jeff with a few questions and he was very helpful.

Please post some pics when you are done!

Altec 604G Markwart xover (1st attempt)

Jeff Markwart's 604-8G crossover

Great info, thank you! I will definitely post some pictures and my results when this is finished!

[Elitopus1]

Well, the value of the cap, or its closeness to a schematic's proposed value, is NOT that important. Most people get this wrong all the time, priority - wise.

What is REALLY important is the QUALITY of the cap, if you want the best possible sonic result.

The quality of the materials and construction is always more important, than hitting an absolute value. It is nice, for values to be the same, in stereo applications, ( which you don't have in mono.)

See my recent post #7, on crossover caps, in my current thread.

So far, its hard to get answers on the question of high quality caps up here. The common goal is " as cheap as possible " and not " as good as possible ". Maybe one should talk to some advanced high-end speaker builders.

Low Ohms .......Jeff Medwin

The comment about only liking caps that are as "cheap as possible" is incorrect. We actually like how oil caps sound. The fact that they are also inexpensive is just an added bonus.

People have been using oil caps and Altecs for over half a century. There is just good synergy there.

[LowOhms]

The comment about only liking caps that are as "cheap as possible" is incorrect. We actually like how oil caps sound. The fact that they are also inexpensive is just an added bonus.

People have been using oil caps and Altecs for over half a century. There is just good synergy there.

Hi there,

Respectfully, Don, I don't think so at all !! Oil Caps are NOT the best possible caps, and I will NOT use them on my ALTECS - ever !!!

They just don't cut it compared to MODERN caps. I mean, IF you are willing to spend the money ( and on occasions I am) there are FAR FAR better sounding caps than mushy - midrangey oil caps. ( People often employ oilers to " smooth out" all the grunge from their poor sounding solid state amps, and poor system wiring ) You just haven't heard it yet - good ALTEC systems with modern caps.

Modern caps are far superior. WE have modern caps, sometimes audiophile, sometimes industrial and designed for pulse applications, that simply, easily, totally destroy ALL oil caps. The problem is, not every one knows what to use. That was the purpose of my other thread. But is seems like everyone up here is asleep, unaware !! Snoozing.

As one example, on a well set up ALTEC ( that ass/u/me s a LOT ) try any 4 uF oil to a 4 uF DynamiCapE ( available from Mike Percy ) with doctored leads. And there are even FAR better comparisons I could suggest, but can't for now, because they are still in the evaluation stage.

Lets get beyond this "mid - fi" and wasting ALTEC speakers' potential, ....and get into high fidelity !!!


Jeff Medwin Low Ohms

[Basplin]

Hi there,

Respectfully, Don, I don't think so at all !! Oil Caps are NOT the best possible caps, and I will NOT use them on my ALTECS - ever !!!

They just don't cut it compared to MODERN caps. I mean, IF you are willing to spend the money ( and on occasions I am) there are FAR FAR better sounding caps than mushy - midrangey oil caps. ( People often employ oilers to " smooth out" all the grunge from their poor sounding solid state amps, and poor system wiring ) You just haven't heard it yet - good ALTEC systems with modern caps.

Modern caps are far superior. WE have modern caps, sometimes audiophile, sometimes industrial and designed for pulse applications, that simply, easily, totally destroy ALL oil caps. The problem is, not every one knows what to use. That was the purpose of my other thread. But is seems like everyone up here is asleep, unaware !! Snoozing.

As one example, on a well set up ALTEC ( that ass/u/me s a LOT ) try any 4 uF oil to a 4 uF DynamiCapE ( available from Mike Percy ) with doctored leads. And there are even FAR better comparisons I could suggest, but can't for now, because they are still in the evaluation stage.

Lets get beyond this "mid - fi" and wasting ALTEC speakers' potential, ....and get into high fidelity !!!


Jeff Medwin Low Ohms

Thanks for your posts, Jeff! It seems to me that the best sound is really in the ear of the beholder, and I've heard as many people rave about the benefits of modern caps as I have the oil. With the sheer number of their fans, it seems that PIO/film oil caps have some legitimate pluses too. Taste in sound, equipment used, and especially the space/listening environment all have an impact on what works. Given the large propensity for oil caps, I think I'm going to give them a go. If I totally hate them, then well, I'll know then where I stand! I will admit too that major reason I think for my choosing these is that the film oil caps seem to be the best value for the money that I can find now. I'll keep this thread posted as to what I find!

[Basplin]

I just went to a local army surplus and found my caps for the Altec - old GE Dielekrol 5 and 7uf. These will go in the HF part of the crossover. I know the more recent Dielekrol's are film oil, but I'm not sure how old these are. Could be PIO? Anybody know? Either way, I think they will sound great!

[Elitopus1]

Very cool. Those should be similar in composition to the newer GE caps. I would try them out and see how they sound

[GM]

Could be PIO?

Non PCB, so no, what they call HAZY film foil. You could do a lot worse [scroll down to pg. 11]: https://www.geindustrial.com/catalog...rmonFiltrs.pdf

GM

[Elitopus1]

Like Basplin just mentioned, there are many people using oil caps who love them. Versus one person saying spend 100x more.