[Roger A. Modjeski]

Yes, there is a new line level preamp coming out soon under $800. We currently offer complete phono preamps with passive RIAA.

[ooheadsoo]

What can we expect from this preamp, what engineering goals, etc?

[richidoo]

Yes do tell, <$800? Yikes!

[hiradi]

Glad you found your way back. Wasn't it Jeffery Teuber?
[/quote]

[Roger A. Modjeski]

The under $800 preamp is designed to match the EM7 series of power amps both physically and electrically. There are two OB2 shunt B+ regulators and a single 12 volt (heater) gain stage. You can use a 12AX7, 12AU7, 12AT7, 5751, 6072, and a few other tubes I am researching.

Simple features, volume and input selector. We will also offer a simple passive EQ option that will bring new life and body to the thin sounding single driver speakers that could use some help in the lower midrange. The difference is astounding. I have auditioned many of these speakers on my EM7 and 45 amps and even the best need some help. Many who own these thin sounding speakers quickly make the excuse (often in a very apologetic tone, "Well, I mostly listen to chamber and solo music". I gently point out that the Cello in a chamber group is a powerful instrument that is not properly heard in a system that starts falling off at 300 Hz.

Most OB speakers start of fall off around 300 Hz because the baffle is no longer able to sufficiently block the back-wave cancellation. Even in a box (ported or sealed) the FE-103 speakers (including mine) start to fall off in this general area. Either we help them with a little, mild, passive EQ or just go on suffering. I prefer not to suffer when such a simple solution is at hand.



Roger

[schotter]

Simple features, volume and input selector. We will also offer a simple passive EQ option that will bring new life and body to the thin sounding single driver speakers that could use some help in the lower midrange. The difference is astounding. I have auditioned many of these speakers on my EM7 and 45 amps and even the best need some help. Many who own these thin sounding speakers quickly make the excuse (often in a very apologetic tone, "Well, I mostly listen to chamber and solo music".

Hey Roger (almost feel like I am hijacking this thread since I have never appeared here),
someone in audioasylum pointed me towards your post since you are describing exactly what's my problem with my small single drivers in combination with my op amp.
Very interested in the EQ option and the EM7 amp. Do you think the 2.5 watts will be enough with 97db speakers?

cheers

kai

[Roger A. Modjeski]

Simple features, volume and input selector. We will also offer a simple passive EQ option that will bring new life and body to the thin sounding single driver speakers that could use some help in the lower midrange. The difference is astounding. I have auditioned many of these speakers on my EM7 and 45 amps and even the best need some help. Many who own these thin sounding speakers quickly make the excuse (often in a very apologetic tone, "Well, I mostly listen to chamber and solo music".

Hey Roger (almost feel like I am hijacking this thread since I have never appeared here),
someone in audioasylum pointed me towards your post since you are describing exactly what's my problem with my small single drivers in combination with my op amp.
Very interested in the EQ option and the EM7 amp. Do you think the 2.5 watts will be enough with 97db speakers?

cheers

kai

I am glad the asylum is sending some people here and I don't mind your hijacking the thread. 2.5 watts is enough if your average listening volume is around 97 dB. Many people listen way below that. You need to get an SPL meter (everyone should have one). I hear Radio Shack has re-introduced the analog one.

What are your speakers? Any response curves or idea of how they behave in the lower octaves? The problem usually starts around 300-400 Hz. I've heard people say "the speaker or amp stops playing bass at X frequency. That's not how it is. It would be more correct to say "This speaker starts to fall off at 400 Hz and by the time it gets to 50 its down several db". That's why the EQ has to be gradual. I don't know of anyone making gradual equalizers so I am. We make one in a nice box with good parts and gold jacks for $150.

My web guy is a little slow lately. Here's the new price list that will go up soon.

Music Reference Price List  2007

Amplifiers:

EM7 Stereo 2.5 watt/channel SE power amp.    $750
EM7 Stereo 5 watt/channel SE power amp.      $925
EM7 12 Watt Monobloc (each)         $950
Stereo 5 and Mono 12 can be supplied any voltage at no extra charge.

245 45 or PX4 based Deluxe Stereo 4 watt/channel        $6,000
245.1  45 based Stereo 4 watt/channel less output tubes      $1,850

RM-10 MK II    35 watt/channel Push-pull EL-84/6BQ5       $1,950   
RM-200 MK II 100 watt/channel Push-pull KT-88         $4,200
RM-300 MK II 300 watt Monobloc Push-pull (each)      $4,750

Preamps:

Pot in a Box                  $135
2 Input Toggle Pot in a Box            $195   
3-6 Input Rotary Pot in a Box add $25 per input to above
Volume and Balance with multiple inputs        (call)

C4 Preamp 2 inputs with Regulated Power Supply   $850
Additional inputs up to 6, add $25 per pair.

RM 4+ 6DJ8/6922 Passive RIAA phono preamp       $950
RM 4 Our classic, first product Head Amp          $750
RM 4 and RM 4+ Two Box M/C phono system      $1,600

Speaker Systems:

The FE-103 Single Driver Speaker (each)         $225
EQ in a Box*                     $150
EQ in the EM7 or C4 preamp*            $100

The ESL-1 Integrated Speaker System         $6,500

*This Passive EQ brings body and fleshes out the lower midrange of speakers lacking in that area. It improves our speaker and other hi-efficiency speakers markedly. No more thin lower midrange to suffer through. The difference is startling.



Roger

[schotter]

What are your speakers?
[/quote]

They are Omega Super 3 XRS hemp speakers. And a TBI powered sub for anything below 100. The problem is indeed above the sub and below what makes the XRS really shine. I was starting to look into tube amps (47 Labs Shigaraki is what I am using right now).

But before I go ahead it might be worth trying an EQ in a box...

[Roger A. Modjeski]

I would say the moderate EQ I have developed is an order of magnitude larger than changing amplifiers. Here's how I look at it. Say you are finishing a very rough piece of wood. You don't start with 400 grit sandpaper, you start with the big stuff, say 80 grit. Then you work your way down through the grits, maybe a few big steps at a time till you get to the 400. So do the big things first and then the fine tuning.

Roger

[schotter]

I would say the moderate EQ I have developed is an order of magnitude larger than changing amplifiers. Here's how I look at it. Say you are finishing a very rough piece of wood. You don't start with 400 grit sandpaper, you start with the big stuff, say 80 grit. Then you work your way down through the grits, maybe a few big steps at a time till you get to the 400. So do the big things first and then the fine tuning.

Roger

Hmmm, just doublechecking (not a native speaker so I am getting confused easier...) if the EQ is an order of magnitude larger than amplifiers then it's rather the 80grit than the fine 400, right?
Making it the 1st thing to try before an amp change?
Thing is I am cautious when it comes to a new amp since I like a lot what my current setup does (speed, pace, imaging) and I would not want to lose the virtues. The problem is probably the 'voicing'. Some things (amplified guitars, brass instruments) are missing some beef in the lower mids and voices end up being a bit nasal and without 'body'.
My setup wins in the small chamber category but fails completely with the 'AC/DC test'.
Actually, a vintage tube friend of mine just said 'why not an EQ?' and that made me think.
But before I warm up to the EQ idea...I am not even sure where I would put it in my chain. The current amp I have is an integrated (47Labs Shigaraki) and there is only a set of 'line out' and three source inputs:
http://www.sakurasystems.com/products/shigaamp.html

cheers

kai

[Roger A. Modjeski]

Yes you are right. In re-reading my analogy it's not so clear. The point is this: No amplifier change alone will fix the problem you have in the low end unless it is an amplifier with EQ built in. This is why I offer the EQ as a box to go between your preamp and power amp. It could also be put into a tape loop if that is available. I also offer to put it into the amplifier thus saving one extra pair of patch cords, jacks, and stuff to deal with. It can be made switchable so you don't have to use it should you audition or buy a speaker that has a good low end.

The point I was hoping to make with the sandpaper is that many who write me expect an amplifier change to fix some problem that is not about the amplifier. I advise them, and you, to get on the big stuff first, get that right and then work on the fine tuning via amps and preamps.

When I listened to several single driver speakers, including my own, I could not enjoy them. I had to make too many allowances for what they could not do. If these speakers were auditioned in a store against some more conventional speakers of similar price, Polk for instance, I can't imagine choosing to take home something so thin sounding.

The promoters of open baffle and other speakers that start to fall off around 300-400 Hz are ignoring something very important. In my experience listening under those conditions requires a lot of mental energy resulting in listener fatigue. Granted these speakers have certain virtues but the loss of lower end is too much to suffer through.

[miklorsmith]

I think this is a great idea, Roger.  I've been using EQ of different sorts in my setups for a while now.

How does this bugger work?  What are the adjustments and what does it "assume" about the problem it aims to correct?

[schotter]

Yes you are right. In re-reading my analogy it's not so clear. The point is this: No amplifier change alone will fix the problem you have in the low end unless it is an amplifier with EQ built in. This is why I offer the EQ as a box to go between your preamp and power amp. It could also be put into a tape loop if that is available. I also offer to put it into the amplifier thus saving one extra pair of patch cords, jacks, and stuff to deal with. It can be made switchable so you don't have to use it should you audition or buy a speaker that has a good low end.

The point I was hoping to make with the sandpaper is that many who write me expect an amplifier change to fix some problem that is not about the amplifier. I advise them, and you, to get on the big stuff first, get that right and then work on the fine tuning via amps and preamps.

When I listened to several single driver speakers, including my own, I could not enjoy them. I had to make too many allowances for what they could not do. If these speakers were auditioned in a store against some more conventional speakers of similar price, Polk for instance, I can't imagine choosing to take home something so thin sounding.

The promoters of open baffle and other speakers that start to fall off around 300-400 Hz are ignoring something very important. In my experience listening under those conditions requires a lot of mental energy resulting in listener fatigue. Granted these speakers have certain virtues but the loss of lower end is too much to suffer through.

Hey Roger,
that's actually good news.
And I checked with Yoshia at 47 labs, I can try using my line-out and a source-in for the EQ, like a tape loop. This might save me from looking for a new amp.
Will send you a PM to order an EQ in a box.

cheers

kai

[Jampot]

I can try using my line-out and a source-in for the EQ

A word of caution - using a source in means you effectively have to select 2 inputs at the same time, the actual source AND the EQ source.

Perhaps Roger could comment on the possibility of putting the EQ between the source and the input, particularly as to whether the source output voltage is sufficient to 'drive' the EQ circuit.

A lot of us use (for instance) Squeezeboxes direct to power amps, if it could work in that position perhaps it can work infront of the integrated, the only problem being that it would only work for one source

If it does, Roger will likely have a rush on his hands

Perhaps the EQ should have thread of it's own....

Jim

[lowrider]

schotter,

I pointed you to this forum because I think EQ will help you more than any change of amplifier, but I also think the reason of your "problem" is that a 4.5" driver cannot be really full-range, except maybe horn loaded...

An active subwoofer, with active bass management, like I use, and my full-range drivers are 10", would be the most effective remedy, with EQ still possibly helping the higher bass...

[rajacat]

Why not use a BSC (baffle step circuit) in series with the positive lead speaker cable to correct the lower midrange rolloff thereby eliminating the extra interconnects needed for an EQ.

schotter--BTW my Omega Hemp Dipoles don't have nasal vocals and cellos sound just fine. They don't sound thin either.I do use a sub for the lower frequencies. Are your XRS's fully broken in? Perhaps, with your present amp, a tube pre might be good medicine.

Raj

[ooheadsoo]

Wouldnt BSC kill sensitivity, which is key when youve got 4 watts to work with?

[schotter]

Perhaps Roger could comment on the possibility of putting the EQ between the source and the input, particularly as to whether the source output voltage is sufficient to 'drive' the EQ circuit.

Yep, that's exactly what Roger said (obviosly a silly idea trying to choose two sources...), we had an interesting chat (thanks for your time Roger!) and I ended up giving the EQ a try, before I get an amp or different speakers.
And no, I guess you are right Jim: I am not really expecting huge amounts of air moved with my 4.5"ers but going a different route speaker wise will be a possible next step, maybe even before getting new amps. Thing is, I really like so many other things about the XRS that I would like to preserve. My subwoofer is active and a little fill between it and the XRS'es upper mids might be just enough to get the right balance for now.
Well, if not, then there is always hemp dipoles, revolutions and a very appealing Fi X or EM7...

but in any case, I am learning a lot.

kai

[lowrider]

The subwoofer beeing active is important, but I also filter the bass out of the stereo amplifier and speakers, that helps even more...  aa

This extremely usefull feature from Roger's 6EM7/13EM7 Amplifier:

Two sets of gold input jacks; one full-range, the other set at 100Hz highpass, 6 dB/octave. (changeable to another frequency or useful to daisy chain your preamp to another amplifier or subwoofer).

[Roger A. Modjeski]

I can try using my line-out and a source-in for the EQ

A word of caution - using a source in means you effectively have to select 2 inputs at the same time, the actual source AND the EQ source.

Perhaps Roger could comment on the possibility of putting the EQ between the source and the input, particularly as to whether the source output voltage is sufficient to 'drive' the EQ circuit.

A lot of us use (for instance) Squeezeboxes direct to power amps, if it could work in that position perhaps it can work infront of the integrated, the only problem being that it would only work for one source

If it does, Roger will likely have a rush on his hands

Perhaps the EQ should have thread of it's own....

Jim

Jim,

You are correct, one cannot take a signal from a line out and go into another input. Here's why. Suppose you have your CD in input 1 and take the line out through an EQ and back into 2. You then have to select input 2 to listen to it and then you loose input 1.

Here is what you can do. If you have one favorite source (CD or Squeeze box for instance) you can disconnect it from the preamp input, run it to the EQ input and then connect the EQ output to the former CD input. In this configuration the EQ is only applied to that one input that goes through it.

Sadly we have lost the "Tape Monitor' input/output on most modern products. This is a perfect way to insert an EQ. The other perfect way is between a preamp and power amp or an integrated amp that has preamp out and main in jacks. Main out alone is not sufficient because there is no place to connect the EQ out. A "preamp out/main input" setup has either jumpers connecting those jacks together or a switch to "break" the path. In either case you break the path, send the signal to the EQ and take it back in the main inputs.