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Tone Control


kevco
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Hello All- This is my first post here, as I have just acquired my first pair of Klipsch speakers. I am pushing my Forte II's with a highly modded Dynaco ST70 preamped by an Aric 3.6 linestage. For those unfamiliar, the Aric uses two 12AU7 dual triodes as a linestage with a volume control pot and switching for three sources, very simple, very affordable, very tube. I am immediately wowed by the Forte's ability to make fine use of the Dynaco's limited power. Who could ever have need for more than 25 watts?!? While the system as a whole sounds wonderful, I am suddenly feeling the need for some tone control. My varied taste in music has me switching from bass heavy rock to more trebly jazz offerings to midrange heavy vocal pieces. I love my simple preamp and would prefer to keep it, so do I have any tone contol options that would allow me to raise and lower levels on the fly? The obvious fix would be a graphic equalizer, but I'm unsure where to place one in my setup as there is no tape monitor loop. Placing it between my source ie: phono pre, cd player or Ipod would have me switching wires endlessly, while placing it between the linestage and amp seems inheritantly wrong. I also worry that an EQ will add coloration to my all tube signal. I wish, simply, that my preamp had a bass and treble knob, but I am not prepared to drop many hundreds of dollars (if not thousands!) on a new linestage. Any and all ideas would be welcomed. I love these speakers!

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Well,

One low-cost approach might be to look in craigslist for a good-but-used preamp or receiver. Marantz, Pioneer, etc. seems to be prevalent in the marketplace.

Here is another site in case you are wanting to spend a little more (I haven't used or heard any of this except for the "audiophile" archival [phono] preamp): http://www.esotericsound.com/elect.htm

Also, Behringer has some parametric EQs and mixers with low price points. For instance:

http://www.amazon.com/Behringer-DX626-DJ-Mixer-Channels/dp/B000972KQG/ref=sr_1_32?ie=UTF8&s=electronics&qid=1252240458&sr=1-32

Otherwise, you might look to build one yourself. Note that tone controls by their very nature introduce distortion, so
discussions about "distortion-less tone controls" is actually an
oxymoron.

Chris

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Welcome to the forum and congrats on the Fortes. Very nice speakers.

I've got a Sunfire tube preamp which has bass and treble contour controls which are nice on occasion. Usually use them to enhance very low volume listening. Other than that don't use them much.

One thing, in this season right after acquiring your Forte's, it could be a good thing to just listen to them and learn by heart their reference sound. That can serve you well as a baseline reference for other changes in your system, such as eq.

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You are in a dilema for the reasons you mentioned. I agree now that you have the Klipsch and are hearing a more open sound the quality of the recordings is showing up. One thing you could do is get a nice switch box so all your sources plug into it and you choose by push button which gets sent to the preamp. Then you could add the EQ between the source and preamp and not have to keep chaning wires. There are some nice switch boxes out there that would work for you. You could also put the EQ between the preamp and amp just to see how it sounds, but I'm thinking the between the source and preamp using a switch box would sound best. I do it with a vintage HH Scott LK-72 and it works great.

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One thing, in this season right after acquiring your Forte's, it could be a good thing to just listen to them and learn by heart their reference sound.

Good advice for the first year of marriage, too. Actually, I'm finding out that just keeping my ears open and my mouth shut still serves me well, after 22+ years...[;)]

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Hey kevco

I posted about this before but thought it easier to copy it here reather than just a link.

I'm using a Behringer DEQ2496 to do this but other brands with DSP processing can be used also.

The "BEST" thing about this setup you can have the best of both worlds which is with the Behringer you can do a hard bypass(relay) and eliminate the unit from the signal path (except fot the relay of course) for the very best recordings that don't need attention but with the recordings that need attention it is easily available.

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EQing..............Its in our equipment,our active and passive crossovers ,our rooms and our recordings!

It's a dirty word to many purist audophiles!!! I myself have used some forms of it in the past and wasn't satisfied with what it offered me but what I'm able to acheive with today's DSP based Crossovers and Equalizers has changed my mind and my system for the better IMHO.

One thing that many people who acheive a very accurate reproduction system will notice is the widely varying quality of our recordings and when very high quality recordings are reproduced through very good systems it can be a wonderfull experience but unfortunately far to many of our favorite music was recorded using bad methods, equipment, and often with an eye/ear on what will sell good soundwise(ie,, over a boombox or car system) instead of trying to faithfully capture the sound of a real event with the best equipment and methods we have today.

Even when the best methods and equipment are used to make recordings there are still many variables that will effect the tonality that the recording engineer heard and recorded versus what we will hear when we reproduce the same recording over our own unique system/room. This alone IMO shows the need for us to have the ability to compensate the best we can for the recordings we want to reproduce in our own listening rooms.

One ear opener for me was about 10 tears ago when I was repairing a Marantz 7C for a friend. I installed the pre-amp in my system and as I listened over the next couple of weeks I noticed how much I enjoyed more of my music by the subtle use of the bass and treble controls of the Marantz 7C.

As many know there are very few high quality pre-amps made with tone controls and even when they do have them they have been of limited use.

Another product caught my attention when it was produced and to me made more sense when it comes to EQing for various recordings was the Cello Palette Preamplifier and of particular interest was the EQing features it offered.

So if anyone has a desire to see what being able to EQ like the Cello Palette would offer them and they own a Behringer DEQ2496 or similar processor I have come up with the PEQ settings that will very closely mimic those of the Cello Palette.

For the Behringer DEQ2496 program into the PEQ Module the following settings:

Freq. B/W(Oct) Gain(db)

20Hz 2 0.5db see note (1)
120Hz 2 0.0db see note (2)
500Hz 2 0.0db
2000Hz 3 0.0db
5023 Hz 2 0.0db
20khz 3/2 0.0db


(1) note: You must program some value of gain into one of the PEQs for the Behringer to save your PEQ module into memory so if something is already presently programed to the PEQ module before you add these Cello Parameters then this can be set to 0.0db also.

(2) note: All PEQs set to 0db Gain will be adjusted as needed depending on recordings.

One great feature of using the Behringer like I am is when I have very good recordings I just place the Behringer in Bypass Mode but otherwise I have the ability to make subtle but very enjoyable changes to the less than ideal recordings.

I would suggest reasonable adjustment limitations so far based on what I have experienced are; the bands of 20Hz, 120Hz and 20khz should be limited to approximately +/- 6db with something around 2db to 4db being more common. The 500Hz , 2000Hz and 5023Hz will often stay within +/- 2db with (1/2 db adjustments being discernable in these bands). On vocal recordings it is really pretty easy to tweek these 3 bands for the best tonal balance and the reproduced image is often improved in a meaningfull way also.

This ability to compensate tonally has definitly improved my ability to enjoy more of my recordings.

Something I didn't expect was how easy it is to use these bands for compensation (because they are very wide bands) and used within reason there effect is subtle yet clearly discernable and I never really could srew up the sound.

This is another tweek I added after forum member Cask05 brought some articles to my attention about room gain. I could easily see a recording being made and the engineer's tonal balance choice being made based on a unique room gain and other variables in the recording studio and even studio monitor system. Also our own rooms unique construction and room gain could easily come into play and after using it I do consider it a very usefull adjustment.

I actually found myself using this more and in preference to the 20Hz and 120Hz PEQs mentioned earlier. For my room and recordings I tried this with I used 100Hz and gains of usually around +2db to +4db maximum for the most realistic reproduction.

Using the Behringer DEQ 2496, program one of the (10 available) PEQs for a Lshelv 6db slope and by varying the frequency from around 100Hz to probably a maximum of 200Hz ( I'm assuming unique room size, types and other variables like modes might alter the best frequency for this purpose) and also by adjusting gain you can again add some compensation for differences in recordings and your own listening room possibly.

Not sure how many have the equipment to do this or interest but I of course would be very interested in anyone elses thoughts on this subject and especially if you have the Behringer or something equivalent and try this.

Note: Remember this EQ program is best and proprely used when used with subtle adjustments and any large increases at the extreme low or high frequencies aren't necessary and could damage equipment and/or loudspeakers.


Enjoy your music!

mike tnSmile

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Please read this Link to the Cello Palette review because it highlights IMO some very important reasons why the ability to EQ is very logical when done properly.

http://www.printthis.clickability.com/pt/cpt?action=cpt&title=Stereophile%3A+Cello+Palette+Preamplifier&expire=&urlID=15374165&fb=Y&url=http%3A%2F%2Fstereophile.com%2Fsolidpreamps%2F692cello%2Findex.html&partnerID=3834

Note: The graph showing the bands and their maximum ranges but of course small adjustments would be the proper way to use this method of EQing.

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Interesting thoughts all over the place...The inherent magc of my very simple all tube system is it's direct signal path straight to the speakers...I have no interest in returning to solid state for this system (as I already have a lovely Marantz 2275 gathering dust..). The very fancy parmetric EQ's are beyond the simple RCA inputs that I have at my disposal. I guess my first plan is to try an older high quality EQ between the source and the linestage. Worth a try. I am only looking to make very subtle corrections to compensate for differences in recording techniques and the sound of my room. I was listening, for instance, to the brand new Beatles Stereo Box Set just this morning. While being a measurable improvement over the 1987 cd masters that we've all been suffering with for so long, I find it to sound very bright on both my home system and in my car. It would be nice to simply turn the treble down a hair, and enjoy the music, but....alas no knob!

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...I was listening, for instance, to the brand new Beatles Stereo Box Set just this morning. While being a measurable improvement over the 1987 cd masters that we've all been suffering with for so long, I find it to sound very bright on both my home system and in my car. It would be nice to simply turn the treble down a hair, and enjoy the music, but....alas no knob!

If that is your problem, then I'd recommend a little room treatment instead. Just a little bit more carpet on the floor, a diffuser on the ceiling/walls, or a bass trap in a corner or two can make a big difference in tonal balance, especially with your Forte IIs, which tend to spread their energy around the room more than say a Klipsch K-402 horn.

Chris

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I can relate to your situation, at least the part about the simple configuration and pure signal. I have a single ended amp with volume control driving my KHorns. I also have a very nice vintage Yamaha receiver (Model R-2000) in my living room (available for background music, so at least it's not collecting dust). I've tried the Yamaha's pream section driving the tube amp, and I gain a lot of control over the sound but I lose a lot of detail and magic.

You might try rolling the preamp tubes. I realize that it may be more trouble than the cable swapping you mention in your original post, but at least you're keeping the signal pure. I roll my 6922s, but just for kicks and not for the reasons you state. There is a significant difference in sound between tubes. I'd suggest contacting a good tube dealer (I recommend Jim McShane, although there are others) and tell him what you would like. They can recommend tubes that will allow you to tailor the sound to your liking. You may find that a more mellow set of tubes and you don't have the issues after all.

Hope this helps.

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If you decide to add a solid state EQ unit in between your preamp and amp, please keep in mind that the majority of tube gear needs to feed a high impedance input (47k-100k ohms). Many pieces os SS gear have an input impedance that it too low (12k-20k), and you end up with a filter that rolls off the bottom end. The output of most SS gear is very low, so it will have no problem at all in driving the power amp.

Bruce

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I suppose that it's entirely possible that what I'm looking for may not exist. I will reiterate that 90% of the time the system sounds exactly as I want it to, acurate, powerful, warm, spacious, airy...I have spent six months rolling both preamp tubes and power tubes. I have been absolutely thrilled with the NOS mid 1950's black plate RCA 12AU7's that are currently in the linestage. I will also mention that the Beatles reissues sound bright to me on every system that I've listened to them on. I was hoping somebody would say simply that I needed get a "Joe Whammy Tube Tone Miracle Box" and all would be good...Perhaps I should invent one...The room treatment is good, the system is even better, but on occasion the sources are only mediocre. Such is life. I'm going to try a used EQ just for fun though.

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I would like a bit of tone control for recordings that need help as well (room is as treated as it's going to get). I think Mike's suggestion is the best, as the Behringer can be completely switched out of the circuit, save for one relay. Plus you have a lot of flexibility in regards to EQ control (and an RTA to boot). Just my 2 cents.

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kevco,

I'm not a big fan of tone controls, I only have one system that has them and I don't use them at all. Horns can sometimes be a bit bright and some guys really like the "bite" that horns can produce (reproduce?). I don't. I hate overly bright systems and really hate it if the system is overly bright and very top end is missing (air). I have found that lamp cord speaker wire and el cheapo interconnects can be a bit bright (ok boys start posting your BS smileys). Anyway I've had very good luck with certain wires and I have no need for any tone controls on any recording.

Thanx, Russ

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I'll take one step up from lamp cord. I use Monster XL speaker cable, and my runs are only 6 feet. Off the shelf (albeit heavy guage Monster) interconnects are all the wire I will ever need. $200 preamp + $400 amp + $400 speakers + $100 tubes = $1100 well spent. Sounds better than anything I could have imagined. If I had $500 more to spend on the system today, would I be better off spending the money on new wires, or a good used Conrad Johnson preamp with tone control? I'd have to take home that preamp...[8-|]

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I've got the DIYTube board for my ST70, but haven't had the time to get it finished (it has a Curcio board in it at the moment). Truth be told, I could live with my Moondog 2A3 amps with no regrets.

Bruce

Hi Bruce-

The DiyTube board is an excellent mod, clean looking and clean sounding. The individual tiube bias feature is top notch. I recommend installing it. I can't say enough good things about Shannon and the forum community over at diytube.com.

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....would I be better off spending the money on new wires, or a good used Conrad Johnson preamp with tone control? ...

What model Conrad-Johnson preamp has tone controls? I don't know all the models but mine didn't have any.

Thanx, Russ

My error Russ, although some phono stage equipped CJ preamps had variable RIAA curves, apparently none had tone controls. It seems that what I remembered to be tone control on a friends early 80's CJ pre, must have in fact been a balance knob...[:#] So sorry!

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