Modified Forte 1 Upgrades-Bob Crites Autotransformers and Titanium Tweeters

[SET12]

Looking at the schematic again and looking at the tube data sheets it looks as though your amp may be rated at 40 watts and after looking at the feedback circuit I come up with 1.32 volts for its rated output on the 8 ohm tap

At 10 watts out again on the 8 ohm tap it would be .663 volts in.

I think this is enough for the Forte's as your amps sensitivity match my amps which are 10 watt amps with about the same sensitivity.

I would think the Curcio modded ST70 may be better in some regards but I haven't heard one yet. The Dyna is not known for the best output transformers. I suspect the Scott are better! I do have a Curcio here for repairs though.

Also you can damage an output transformer without noticing anything in particular going on with a no load on the amplifier by high voltage arcing over the windings insulation.

My Forte mods run today twice of what the Forte's sold new. But then again their performance is worth 10X or more then what they sold for new.

With various mods YMMV but well worth the effort IMO.

SET12

[PDXMike]

Well, it turned out my analog MM was not reading ohms properly, so I went out to Frye's and picked up a new one. Both tweeters are dead. The squawker (K-53-K) in the speaker I was getting some odd sounds from reads 12.8 and the woofer reads about 4.4. I think I remember those figures being about right.

So, on to the rehab.

Mike

[SET12]

Yes Mike,

I just read mine which is one heck of a lot easier than what you had to do.

I got 12.2 ohms for the Squawker so I think your fairly safe and your bound to hear the squawker reacting in strange sounds from applying the DC to it.

I do hope you replace the tweeters with Crites Titanium diaphragms as I think you'll find them a real enhancement over the stock ones being so much smoother!

SET12

BTW I have been consulting with an AK member on his Forte crossover mods which he has decided to go with the North Creek 12 AWG Inductors after much discussion. He has also decided to use Mundorf "M" caps for his woofer and tweeters and will be using the Mundorf Silver/Oil for the midrange. He'll also be up grading his Autotransformers and tweeters. Hopefully he'll post the results of his work.



1.0mH Music Coils in 14 AWG, 12 AWG, 10 AWG, and 8AWG

And as you know I am using the 8 AWG which I enjoy immensely.

[PDXMike]

I'll be ordering the Crites titanium diaphragms based on all the positive comments in this thread to start. Then I'll do something about the X-over.

I imagine that the Forte's will sound better with ANY working tweeter

I'm actually pretty embarrassed that I hadn't noticed this before. My excuse is that I haven't been using these as my primary speakers; I had been using these as fronts in a Forte and Heresy-based home theater set-up (I decided that I didn't really get a whole lot out of it and sold everything off except the Fortes). But still....I hope my ears aren't that bad.

Thanks again. I'll post again when I can review the new titanium diaphragms (although all I'll really be able to say is "Hey, I've got high end now!")

Mike

[SET12]

Hi All,

A Member of AK that is building a Forte Outboard Crossover told me that their were just 3 photo's that he was working from so I decided to take some updated ones which include what I feel are IMO of the best speaker crossover components manufactured today, Duelund.

From these photo's I would think one could easy derive all its connection points.

[David Pritch]

Your crossovers are a true source of inspiration. Are you still using the Mundorf silver/oils on the tweeter circuit? For my Klipsch KLF-20 the tweeter calls for two 2.o uf caps. Mundorf and Clarity MR caps seem to come in 2.2 uf values. How much would this lower the crossover frequency? Did you buy your caps as matched pairs? Or does one just go to an all Duelund cap system despite the cost.
Thank you again for your unselfish and pioneering work.
David Pritchard
575-644-1462

[SET12]

Originally Posted by David Pritch

Your crossovers are a true source of inspiration. Are you still using the Mundorf silver/oils on the tweeter circuit? For my Klipsch KLF-20 the tweeter calls for two 2.o uf caps. Mundorf and Clarity MR caps seem to come in 2.2 uf values. How much would this lower the crossover frequency? Did you buy your caps as matched pairs? Or does one just go to an all Duelund cap system despite the cost.
Thank you again for your unselfish and pioneering work.
David Pritchard
575-644-1462

Hi, Dave

Thank you very much!

Yes, I'm still using the Mundorf Silver/Oil's and like them very much!

Yes, I would use two 1uf caps in parallel if you have to!

2.2uf I think would be a bit much I wouldn't risk it! its very easy to damage a tweeter going lower than what it is designed for.

Yes matched pairs!

Duelunds are very expensive! Depends how much you love the KLF's

They are some of the finest!!!

If you have a crossover schematic I'd love to see it!!!

No, Thank you Dave for your appreciation!!!

SET12

[David Pritch]

Thanks to SET 12's experimentation and inspiration, I ordered the Duelund VSF copper midrange and tweeter capacitors through Partsconnexion. The KLF-20 speakers take 2.0 for the tweeter(2 per speaker) and 1.25 for the midrange(1 per speaker). These have to be made at Duelund so it may be a 6-8 week wait.
Mike and Chris (the owner) at Partsconnexion were quite helpful in taking my order. Next I have to order the air core inductors. The KLF-20 uses 2 -10 inch woofers. The woofer value is 1.6. I am wondering if 10 guage will work. The 8 guage are costly and I stii might want the crossovers mounted inside the speakers, as are the current Crites crossover network.
SET, what is the name of the connectors you are using between the components and who is your source?
David Pritchard

[SET12]

Originally Posted by David Pritch

Thanks to SET 12's experimentation and inspiration, I ordered the Duelund VSF copper midrange and tweeter capacitors through Partsconnexion. The KLF-20 speakers take 2.0 for the tweeter(2 per speaker) and 1.25 for the midrange(1 per speaker). These have to be made at Duelund so it may be a 6-8 week wait.
Mike and Chris (the owner) at Partsconnexion were quite helpful in taking my order. Next I have to order the air core inductors. The KLF-20 uses 2 -10 inch woofers. The woofer value is 1.6. I am wondering if 10 guage will work. The 8 guage are costly and I stii might want the crossovers mounted inside the speakers, as are the current Crites crossover network.
SET, what is the name of the connectors you are using between the components and who is your source?
David Pritchard

Dave,

First off, Welcome to AK!

Its a nice feeling that this thread inspired you to post your first couple of post's as I see you have been a member for a while.

Your project should be very interesting! And this can get expensive! But it pays big dividends depending on what you make for choices. And just what you're using for gear!

Once more it is possible to get some of the Klipsch Palladium P-39F performance at a fraction of its price!

I was fortunate to be able to hear a pair and was really able to appreciate just how valuable DIYing can be.

You have purchased some of the finest caps that I have ever heard that have a smoothness that has to be heard to be appreciated!

Duelund spent his life pursuing the finest sound possible and you will hear some of it no doubt!

If you can post the schematic of it I'm sure a lot of people would like to see it!

And if some of your choices will involve compromises then the schematic will be all the more helpful in soliciting some opinions.

Pricing http://www.northcreekmusic.com/COILS.html

10 AWG is fine for the woofer

I would recommend the 8AWG for the tweeter due to its size for the money its not much difference in cost from a 10AWG

And of course I do highly recommend the North Creek Inductors.

For their reasons posted on their site above in Inductor FAQ's
You'll see this by scrolling down the page.

Without a doubt not all Inductors sound the same IMO based on what I heard from a Solen Litz vs North Creek tweeter Inductor comparison I made. Perhaps its just preference and voicing to my system but never the less they were dramatically different with my preference for the North Creek in its sheer body and smoothness. The Solen was clearly thin harsh and wiry sounding.

My main reason for doing my crossovers Outboard is that all Capacitors are Microphonic meaning that acoustic energy can affect their sound!

And it makes auditioning various cap and resistor flavors very easy!!

Many very high quality speakers will have a separate compartment for their crossovers just to get away from the Microphonic's issue.

To what level you hear is determined by the rest of your gear!

My own is so high that it will resolve the grain of analog tape being from coarse to fine grain.

I recently had a $4000 CDP here that while it could resolve the fact that a recording was made with analog tape it couldn't resolve the grain composition. Though the CDP was superior in its liquidity it seemed it was hard to tell if the liquidity was a fact due to lower resolve or a superior low jitter level of playback! as a result of that comparison I have just ordered a Burson Clock for my highly Modified Sony X77ES Burson Discrete Op Amp equipped CDP, It also has a 150,000 uf supply that is as large as some HT receivers in energy storage (Joules) along with a regulator modification that is unique. The foundation of the player was really expressed by the North Creek 8 AWG's to be sure! It certainly put a smile on my face!

And of course I don't use a preamp but use my CDP direct, We did his as well!

I might add we are going to have another face off after he dumps some $1700 more into it in mods! I will of course have the new clock at a $120 DIY investment along some new wide bandwith shielding called "TI Shield" from Percy Audio. It will be interesting!

Here's the connectors or Distribution Blocks as they are called

Here http://www.parts-express.com/pe/show...number=265-800



SET12

[David Pritch]

Thank you for the recomendation on the inductors and connectors. I also like the simple system. My Modified Marantz SA-11S1 runs directly to an Art Audio PX-25 amp. I think these low watt systems do bring out the best and worst of components such as crossovers.
David Pritchard

[SET12]

Originally Posted by David Pritch

Thank you for the recomendation on the inductors and connectors. I also like the simple system. My Modified Marantz SA-11S1 runs directly to an Art Audio PX-25 amp. I think these low watt systems do bring out the best and worst of components such as crossovers.
David Pritchard

Hey you're SET

I have heard the amp! It doesn't get much better than that

A set of world class crossovers will do wonders!

SET12

[SET12]

Well David,

I think I was a little brief with the above post!

I want to tell I am impressed with your system!

It has been some yrs since I heard the PX-25, But I will tell you, I won't forget it! It was one of the sweetest SET's I have ever heard no doubt.

And I can see this reviewer liked your combination as well! Using it himself with KLF20's

http://www.artaudio.com/px25_audiophilevoice.html

As to your player all 31lbs of it!

http://www.stereotimes.com/cd122005.shtml

I'd like to make some comments about the KLF20 which I think is a better choice than the KLF30 for various reasons when time permits.

Here are the two schematics

KLF30

So what don't I like about the KLF30?

Well the expense is one thing!

If David was doing these it would cost a lot more!

Cost wise for North Creek 8AWG Inductors for comparison and Duelund VSFCopper Caps is.

$172 for the 1.35mH

$196 for the 1.75mH

$56 for .16uH

$276 for a 6uf Duelund

$360 for a pair of 2uf Duelunds

$1060 Total Cost For a KLF30



KLF20

Now for the KLF20 which I like a lot.

$172 for the 1.6mH

$56 .16uH

$166 for 1.25uf Duelund Approx. these have to be custom made So I'm guessing here.

$360 for a pair of 2uf Duelunds

$754 Total Cost For the KLF20


So the KLF20 offers a $600 savings in the project right here




So in the end if one is looking at various speakers to use for such a project you have to consider the network that is being used!

Otherwise your looking at compromising! Or much more cost!

Also what I don't like about the KLF30 is the series resistance in the Squawker network which I think can be damaging in dynamic response L-Pads typically are depending on the severity of cut even if one uses Duelund Graphite Resistors Here which have a negative temperature coefficient which enhances dynamics.

Also I would very well try a 39R Duelund resistor in the KLF20 tweeter network. Most if not all tweeters have a rising high frequency impedance. This comes across as harsh if not treated. Adding a resistor also protects tube amps from getting damaged here do to a high frequency no load situation should a tweeter let go.

I once heard a demonstration by an Engineer of how much the response smooths up by having a resistor in parallel with a tweeter!

When I switched from an Ohmite to the Duelund it was a very audible improvement which I was greatly surprised as it was in parallel and not in series. I might add I bought the Ohmites from North Creek which was their choice in sound quality after voicing dozens of manufactures. But in the case of the Duelund it wasn't even a contest.

[David Pritch]

I will be ordering the North Creek inductors for sure. I am going to have to find my original crossovers to see how the speaker wires hook up to the crossovers. The schematic does not show bi-wiring but the back of my speakers have 4 terminals. To me the KLF-20's do sound better with 2 runs of cables to each speaker (using Audioquest).
I am thinking a butcher block would make a good stable external crossover platform. Maybe Vampire speaker binding posts-5 per crossover. Two for speaker cables in and three for running the wires to the woofer, mid, and tweeter.
I would appreciate input on the hookup wire. Solid core copper, stranded copper-silver plated or?
Any thoughts on putting these quality crossovers in a box and covering the outside of the box with copper foil to possibly decrease RF noise.
The Marantz uses a lot of copper.
A new topic is the tweak of putting a 1 1/2 inch copper coupler, also called a copper union on both end of the CD player's power cord. Have it touch the player's metal box if possible. Available at Lowe's and many hardware stores. Cost is $10.00 and if you don't like the sound change you can return the pieces of copper for a refund. Worth a try.
I have great memories of Wisconsin going to Oshkosh for the airshows in the 1980's.
David Pritchard

[SET12]

Originally Posted by David Pritch

I will be ordering the North Creek inductors for sure. I am going to have to find my original crossovers to see how the speaker wires hook up to the crossovers. The schematic does not show bi-wiring but the back of my speakers have 4 terminals. To me the KLF-20's do sound better with 2 runs of cables to each speaker (using Audioquest).
I am thinking a butcher block would make a good stable external crossover platform. Maybe Vampire speaker binding posts-5 per crossover. Two for speaker cables in and three for running the wires to the woofer, mid, and tweeter.
I would appreciate input on the hookup wire. Solid core copper, stranded copper-silver plated or?
Any thoughts on putting these quality crossovers in a box and covering the outside of the box with copper foil to possibly decrease RF noise.
The Marantz uses a lot of copper.
A new topic is the tweak of putting a 1 1/2 inch copper coupler, also called a copper union on both end of the CD player's power cord. Have it touch the player's metal box if possible. Available at Lowe's and many hardware stores. Cost is $10.00 and if you don't like the sound change you can return the pieces of copper for a refund. Worth a try.
I have great memories of Wisconsin going to Oshkosh for the airshows in the 1980's.
David Pritchard

Well David,

I don't think you'll regret the North Creek! I know I'm sold!!

As to the your 4 pairs crossover binding posts I am curious as well! Perhaps you could e-mail Klipsch's Service Dept. they are usaually more ten willing to help out!

I might add as easy as these networks are its easy to misinterpret the wiring.

As to Audioquest, I use their wire as well.

Which I used to wire my crossovers. I also used it directionally.

What I did is to take some used AQ Midnight single individual strands for extension wires on my caps if I had to.

And all the multiple grounds I used multiple strands in new polyester stretch sheathing with crimped ends that were spades or straight flat pin that could be clamped down in the gold distribution blocs.

I did use multiple strands for hot connections as well like from the low frequency distribution block which has the low frequency inductor output connected to it. to the positive woofer output terminal post.

And I see I also used multiple strands on the Autotransformer wiring which you can see in the last photo's

When I say multiple strands I probably took either the negative leg or a positive leg of the AQ Midnight to do this with.

As we know wire is audible though subtle from comparisons of stranded in connections from my amps those subtleties can get to be like mountains once known!

I am not a fan of stranded wire due to its change in sound over the course of a few yrs due to oxidation causing skin effects bleeding from strand to strand which lead to a very blah sound quality which I have heard! With insulated individual strands this isn't an issue.

So I have AQ Midnight for my woofers internal and external, I have AQ Indigo for my mids and tweeters and I picked up used from a local dealer a 2 meter pair AQ Clear to run from my monoblocks to the crossovers.

I don't think I spent $150 for the $1500 retailed AQ that I used.

So I'm a big advocate of used wired.

Any thoughts on putting these quality crossovers in a box and covering the outside of the box with copper foil to possibly decrease RF noise.

While my CD player like yours is copper lined I haven't thought of putting the nework in a copper lined box.

But if I did I wouldn't use just plain copper. I would likely use "TI Shield" available from Michael Percy Audio. This was developed for the Military for eliminating RF and low frequency EMI as well since plain copper does not absorb low EMI very well. TI Shield was a result of the Libyan conflict when some of the smart bombs were not so smart! Due to all the RF in the air. Counter point used this material in there amps and preamps very effectively. I have some of this that I am going to use on my CDP chips in my Sony RF is funny stuff with a mind of its own it seems! As I work with the stuff and see how it losses energy in cabling and on circuit boards wher even the amount of solder can effect it.

I'll look into the copper union thanks.

I use a thing called "The Plug" from

http://www.essentialaudio.com/creative.htm

Its the darnedest thing I ever heard! Plug your player into it then the plug into the wall or your conditioner. Which case I use 3 Furman Power Factor Correctors one on each amp and one for my front end.

But anyway the thing makes your player really sound more analog like and everyone heard this in my local audio club. All's I know is I can hear it!

Even one Furman is beneficial these warm up a system helping with body and punch not to mention their unique protection circuitry which has protected my gear twice from line voltages exceeding a 136 volts.

Furmans counter the effects of Inductive AC lines very effectively I might add! They use this in their best Line conditioners which was reviewed by Stereophile Magazine.

Line Inductance is a very serious problem in some areas. Since havin these I don't have power quality issues that I use to be suspect of.

Yes, I live about 30 minutes away from EAA on the North side of Appleton just off of HWY 41.

Oskosh EAA is better than ever no doubt. A far cry from the 80's.

Last yr I was just feet from a P38 Lightning starting up and taxiing to a runway. My favorite WWII plane also the greatest WWII ace Richard Bong of Wisconsin his favorite aircraft that he flew of all aircraft. I saw Glacier Lady featured on National Geographic.

SET12

[SET12]

Just a quick note!

My private messaging was disabled for some reason and has been just restored!

I hadn't noticed it till clipper informed me of it on one of his threads.

So if there are any questions I would be happy to help!

The is as great as ever

Thanks

SET12