New preamp, loss of low freq.?

Hooked up new preamp, and I lost what I think is some low freq slam. Reasoning behind this?
i have been rewarded with the best cleanest, accurate midrange/highs I have ever heard, but did lose some low frequencies.      Normal?  

Sanders preamplifier is the new addition. 

Should i I hook up my equalizer to  smooth out, and add some low freq. 

it it is recording dependent, I still feel I lost some bass when sanders is in the mix. 

Not complaining, this has completely opened up my energy rc-70's, I have never heard these sound so loud, so clear before.   It's I feel I lost a few octaves in the lower register. 

Better? Leave it, I can definitely get used to this sound, as before it was a small bit boomy, maybe I just need time to adjust, and to let the pre warm up for a couple weeks. 

thoughts, recommendations, tweaks? I suppose I could move the speakers a little closer to the wall, this may add a little more bass. 
I did change speaker wire, I hooked up 16" cables with banana plugs with true 8 awg wire, short runs to speaker, this definitely helped with the damping factor.  I am using auqioquest quartz cables.  

I will ill be getting some groneberg Quattro ref rca's in a week or two. Maybe this will add the missing low freq a little bit. 
If the preamp is brand new I would give it some time to break in, about 150 hours, before you make any determination.
Roger says how it sounds after the first hour, is what one will get indefinitely.  
If the preamp is brand new I would give it some time to break in, about 150 hours, before you make any determination.
Of course, listen to atmasphere and give it some time. But, what amp are you using and are you going balanced or single-ended?

Conrad Johnson / McCormack DNA-750 monoblocks.  Are the amps I use.  I don't think the sanders has enough output volts to fully drive them???  Not sure

unbalanced rca. Buying new rca's in week or two. Groneberg Quattro ref with wbt connectors
Volume to 99 digital, I don't get volume until I reach almost 50 , from 50-99 is my range. I can set pre to add additional 18db gain,. 

Great pre, won't be changing for long time

If the preamp is designed right, then there can be one reason for the loss of bass. If the preamp has an output coupling cap and it is not big enough (in uf) if it sees a low impedance input of the next component.

 So the question is what is the input impedance of the next component after the preamp (EG: amp or xover etc.)

Cheers George   

Amps input imped is 10 kOhms

preamp: output 50 Ohm
input imped 47 KOhms

max output 10 volts

b&k output is I think 17 or 21. Pro 10 mc

onkyo p-308 not sure

Amp 10kohm, this could be the problem if your preamp is capacitor coupled on it’s output. As if the preamp’s output cap (if it has one), the size of it could have been calculated for a more normal (industry standard) >47kohm input impedance power amp.

Which the size of the cap may have been done so it’s say -3db at 10hz  with a 47kohm poweramp. Which is fine. 

But if that amp is 10kohm input then the -3db point will be 4.7 x higher at 47hz  easily heard and so will sound like it has a bass roll off. 

To test this, you can find out if the preamp is capacitor coupled by talking to the designer, or a quick test is to get another amp that you know is >47kohm input impedance and see if it still has a bass roll off.  

Cheers George


Amp 10kohm, this could be the problem if your preamp is capacitor coupled on it’s output. As if the preamp’s output cap (if it has one), the size of it could have been calculated for a more normal (industry standard) >47kohm input impedance power amp.

Which the size of the cap may have been done so it’s say -3db at 10hz with a 47kohm poweramp. Which is fine.

But if that amp is 10kohm input then the -3db point will be 4.7 x higher at 47hz easily heard and so will sound like it has a bass roll off.

To test this, you can find out if the preamp is capacitor coupled by talking to the designer, or a quick test is to get another amp that you know is >47kohm input impedance and see if it still has a bass roll off.

So, I purchased a amp or preamp that is a mismatch? And won't sound good??  Wtf, I'm always fuc**ng something up. 
Tried for a stellar system, and always something wrong when I make a purchase,    Always!!!! Damn.

what is recommended? Sell preamp?

Yes, the amp's input impedance is extremely low at 10kohm, and is not a good match for this preamp. But the preamp's output impedance is very low, so an amp with an input impedance lower than 47kohm can be used for testing, correct?

If he can borrow an amp with an input impedance of >25kohm approx., it should be adequate for testing. Your thoughts?
From a design perspective, why does the McCormack have such a low input impedance?
Yes, inquiring minds want to know............
Made by Conrad Johnson, does it have to do with impedances of tube preamps, or ones that CJ makes?
Tube amps and preamps typically have higher impedances than SS.

If and I state if, this preamp has an output coupling cap this could be the problem as I’ve outlined above, it has nothing to do with the output impedance of your preamp which is nice and low at 50ohms being solid state, it's to do with the output coupling cap size if it has one.

As for poweramps that have 10kohm input impedance, yes this is very low and I really have a hate for this, not only does it create problems of preamps with to small a coupling cap as you "may" have.

It can also create this problem: 10kohm input impedance on power amps can also create problems with output impedance of passive or active tube preamps that have high output impedances, but this is another problem, and not associated with the preamp you have being solid state. 

Cheers George   

George, of course you're right, it's not an impedance mismatch...I'm terrible at math.
The only way to know if there's an output coupling cap is to call the company since this preamp was designed to mate with the Sanders amp.

Or you could just use another poweramp that you know is 47kohm or higher, and if that then gives you the bass your missing you know the output coupling cap is not big enough in the preamp when it’s with the 10kohm McCormack amp.

You also asked why they make such low impedance amps, sometimes it’s because they’ve use Bipolar input transistor, if they used Fet transistors on the input it can be much higher, even 100-200kohm.

That was the nice guy in me talking.

This is the nasty guy talking now. Some manufactures make it low purposely for a reason, so only their preamps that are dc coupled or have large coupling caps and low output impedances work properly with this sort of amp, and many others don’t, especially many tube ones because they are nearly all capacitor coupled and or high impedance, this gives them a sales advantage for selling their own preamp with that poweramp when an A/B is done.

Cheers George 

I do hate low impedance amps - I have Mcintosh 501's that are 10K and do not work as well with my CJ preamp.  I have a Classe with a 75K and the combination is much more dynamic.

George - good call on the output coupling cap...
So should i return the pre, look for a pre which is more compatable with my amp?  The pre is quite nice, it definitely opens up my speakers quite a lot,!
I do have bass, it just isnt as thick as before this preamp. Definitely some is gone. 

Anything else i can do

The preamp does not have any capacitor in the output circuit. It has a very low output impedance of only 50 ohms, so it will drive an amplifier of extremely low impedance without any problems. What this means is that the preamplifier is not rolling off the low frequencies of your amplifier. The preamplifier has linear frequency response (as do all other quality preamps).

The solution to your problem is to use a DSP (Digital Signal Processor). With one of these, you can adjust the

thoughts on this???
I suppose if I knew these amps were hard to drive, I would have bought others which are more compatible ,  so I'm stuck, and blew my whole fuc**ing rat hole money which I saved for almost 5   Damn years for new amps, stereo, and I end up buying something which is not compatible with many preamps, because of some impedance output, f'n great, just great. Now I'm stuck with them, goddamnet !!!!!!!!!!!!!!!!!!!!!!!!!!!

nothing has ever gone correctly for me, I buy a new amp, breaks shortly after, preamps, with problems .  I'm just gonna buy a Bose wave, and be done with this whole schlock, impedance, I or, output, capacitors, f this
The preamp is just very accurate, neutral sounding.  What I put in is what is going out, nothing more, nothing less, with the onkyo, it was boosting the low freq, per the specs. I guess I am not used to a neutral sound, reproducing exactly what is fed into it, through the speakers without coloration in the slightest. 

I do do have bass, just not as boomy as with the onkyo, it is more controlled, tight, than before.   

I dont know, with all this happening, I still feel. Maybe I bought lemon amps, with their goofy impedance of 10 kohm.  

On on a good note, my speakers are a warm speaker, which makes for a descent combo really, as the highs are rolled off at 600 , so even with the rolled highs' the sanders pre, and McCormack amps really do make a good sounding combo feeding my Energy's. 

I will ill give it a year, or maybe a little longer, to see how I like it. 

arctikdeth, take it easy or you'll blow a gasket.

We now know that the preamp is not capacitor coupled, and can drive the McCormack's 10kohm input load fine 

What was the preamp you used before this Sanders that gave you bass?

Cheers George   

Please give it 200 hours. Keep it playing and you will be happy. All gear needs to run in. That is the "issue". 

 prior to the sanders I was using an onkyo p-308 from 1989. 
Also, a B&K pro 10 mc.   The onkyo is adding low freq, the B&K is closer in sound to the sanders I think,.............

will ill try to breathe, promise, I've just had such bad luck over the years, equipment, a job I wouldn't wish on my enemies, and other stuff as well. Sigh- the preamp does not have a sub output, I hate mucking around with eq's. I still have my old onkyo eq from. The early 90's, pristine shape, maybe hook it up one night and see what can be done.   

Oh boy, . 
Thank you to everyone who has helped me. Merry Christmas this season, to you and your families.  


As far as the missing bass.   I am using audioquest Quartz cables from 1991 or a1990, I'm sure things have changed since then. I will mess around with cables, and speaker wires also.   Hopefully I can get back a small portion of my low end, then all will be prefect. 

 It's 2:30 now, time for a Negro Modelo !!!!  Have a good evening everyone. 

Just looked at the Onkyo P-308 and it has a switch, similar to a loudness switch but without the HF boost, it only boosts from 200zh down. Maybe you used to have this switch on when you used to listen to it, and your Sanders pre is not going to give that.? Anyway you've now learnt something about capacitor coupled outputs.

From Onkyo:

"A contra-bass switch is added for those in need of more guts down below but only at 200Hz."

Cheers George

I always had all buttons off!, no contra bass was ever used. 

 Even with all the extras off, I had more boomy bottom end with onkyo.   Strange.  

Will output put volts have something to do w it? 

Sanders is only 10 volts.  

Onkyo and B&K were min 17 or 21 volts for driving the amp. I was using more of the amp, compared to the sanders

Post removed 
I will hook up my onkyo eq-540 equalizer, keep everything at 0 and just lightly boost the lower freq, just a little bit.  Hate using an equalizer, but I don't have a choice, the sound I'm getting from the preamp is remarkable to say the least. Mids/highs NEVER sounded so crystalline / accurate before. Onkyo, mids & highs were recessed quite a bit more. Not as clean.  

Maybe be its a trade off' lose a wee bit of bottom end, and gain exponentially in every other aspect. Worth it, sure is!!  Will let burn in for  2 weeks, will report back. Thank you all. 
I have a thought, the Groneberg Quattro ref ICs may have more low-end extension than your current cables. But let them burn-in before making judgement.
 IME, installing Cardas Clear Light from my pre to amp added deeper bass and more weight to the sound.

You can also contact The Cable Company to find a low capacitance IC that has good low-end specs.

"Will output put volts have something to do w it?"

No they both have enough volts, unless you had to turn them up full volume only still not to get to your listening level you wanted.

"I'm getting from the preamp is remarkable to say the least. Mids/highs NEVER sounded so crystalline "

This will nearly always be the impression, if as you say you have lack of bass.

Cheers George

I will be getting new cables, I called klaus at odyssey with money ready to spend, he said not til 1 week from now, he's going on holiday. Son of a ........I get ready and now I have to wait longer. My 1m pair are stretched very tightly from amp to preamp as it is, which is why I wanted to order the 1.5m Groneberg from klaus asap

i hooked up an old toshiba sd-4000 dvd player to use as a source, and mother fuc**** the bass is in full force.   I was using my iPods at 128k to play through the preamp, and at 128k, I'm sure a lot of the low and highs have been left out during the sync to the iPod. I'm such a dipsh*t. Don't yell at me, it didn't hit me until I played some megadouche (peace sells), and some helstar (king of hell) cd's, the bass was massive, and so was everything else.  Mercyful Fate is insane good now. 

Also, the pioneer elite dv-48 I was using as a source, was giving me some very audible static noise from tweeters, why, I don't know, I pulled it, and now %85 of static is gone. Only a small bit of the same static noise is audible, maybe from house ac line, I don't know. 
I will be getting a new CD player, most likely the NAD 565 for my source, my last CD player purchase was the acurus acd-11 which shows the last time I bought equipment, and the B&K pro 10 mc also back in early 90's.   I am sure bass is back, as I played some same songs I played from iPod, and played the cd, and night and day difference.  I am such a moron!

i am still investigating the bass issue, as I'm not completely sure a good source is absolute, I'll be back.........
Hi George, I have a EE design question.
When no output coupling cap is used, can't DC be outputted into the SS amp? In tube to tube, this isn't a problem, but what about DC transients from a tube pre entering a SS amp when the design of the amp's input stage is unknown?

In our case here, we don't know if the amp is DC coupled. Is it standard to use a capacitor to block DC in modern SS amps?
An iPod at 128k ?

arctikdeth, I'm losing respect for you.
Many power amps use servo on DC (very  low frequency NFB), that might become unstable with low input frequencies.  For that reason amplifier's low frequency is often limited (in my amp to 5Hz).
Hahahaha. Nooooooooooo

 I know, I know, I'm a full on dipsh*t.  Live & learn. 

Happened years ago, when I didn't know about lossless, aac, what the fu*k a nitrate even was.  So I have all my cd's, and many of my lp's ripped to my iTunes, at AAC (256) I didn't know what it all meant, now I do, it sounds great anywhere else, except for my main rig, where its resolution is bad when played through very good equipment. 

It it took me several years to import all my cd's into iTunes, that in itself is another mess I'm not talking about. 

Im not reimporting 3000 cd's and all my LP rips now all on taiyo yuden cd-r's.  Back to iTunes, will take longer as I'm not as hung ho anymore.  So I'm gonna live with the 256 versions. I will re arrange your iTunes, put all the live stuff, so I can load iPod back at 256 k, and not the 128 I was using. Hopefully this will help a little. We moved, so all my cd's are in boxes after 1 year, I hate it, but no room to display them anymore.  

lowrider57 hi.

Just one example, just about every piece of gear cdp, dacs, preamp and amps made by Krell is dc coupled. And there are many many others ss brands that do too. 

Tubes are a different story "most" tubes amps, cdp, dacs and preamps are have massive dc offset, to block this they either have capacitor coupling or are transformer coupled. 

Cheers George

Thanks for the explanations, fellas.
To me it looks like preamp does not provide sufficient output to the poweramp input. It also has user-adjustable gain.
Get the right gain settings and you're happy camper.

If he can get the levels he wants to listen at, there is no problem with "output" voltage from the preamp. 

Cheers George 

I get my volume, and then some, as well as bass, and everything I need!!! I have zero more to say about the bass, sound of my system. I have found my last amp, preamp for my ref system. Cables and CD player are on Santa's list, and time to re-import all 3000+ cd's in lossless.  I wish those 1TB iPods weren't a f'n thousand dollars though, would love to have that, using iPod is so convenient through stereo.  

Changed a letter in my screen name. Same ol me. 

I had a similar experience. Rebuilt some circuitry in my Parasound JC-1 power amps, and the midrange detail was significantly enhanced. But it appeared I had lost bottom end. All my Parasound equipment is direct coupled and uses DC servo controllers (no coupling caps).

I put a wide band pink noise source on the power amps and they were dead flat to below 10 Hz. So all I can conclude is the enhanced upper end detail has shifted my perception of a thinning bass, but it is not there in reality.
This is a really good example of how the MP-3 is killing music :) People think that the bass out of an MP-3 player is how it should be, and it just isn't.

High End audio isn't all bells and whistles generously polished with snake oil... The fact of the matter is that you can hear more with good high end equipment and the problems with mid- or lo- fi suddenly become really obvious!
Yes!  Playing a cd i do have a little more bass. But i think the pre is slightly voiced to mid /high freq, for sanders electrostatic speakers which require this for the panels to become crisper.  Just my opinion. 

The pre is very neutral/accurate.  I think it may work better on my cerwin vega d9's which are boomy, maybe a good combo, im also looking at the para p-5 and nad 165bee pre.  1k each. Might help with the bass with my ref system. 
Help me understand what happened here, i posted this in cables also

i bought a rocketfish rf-acnt2 component cable,. The 30 pin for older ipods etc, with component cables and usb on other end. My volume seemed to go up about 5x as loud vs using the 3.5mm jack on ipod to rca to preamp.  Did i bypass the output of the ipod? Why did the bass, high, mids go up in volume 5 fold?  Holy crapper, this is amazing. I thought my cd cheapo sounded good,.  

Someone please explain.