I have a problem that the gain is too high. I can only turn the volume knob to 7 o'clock position, with the 0 at 6 o'clock. I am sort of ok when using my computer where I can lower the volume in iTunes. But from my CD player, I cannot. I am using Maverick Audio DAC, PrimaLuna Progloue 3, McCormack DNA-1, and B&W CDM9NT.
is that my equipments are out of synergy? I just bought a pair of Zu which is 101db sensitivity, does that mean it will be a even bigger problem? should I buy another preamp with less gain, or should I buy another amp with less power output?
I tried connecting the DAC directly to the amp, the sound is not good. I also try to lower the volume on the DAC. Although it gives a more usable range for my preamp, it has a small impact on the sound. Lowering volume on iTune sounds better.
I think it is usable as long as I use iTunes, but the next thing I will change would be the power amp, or I will get an integrated. I will get the Zu this week and see how it work.
BTW, tube amps are expensive. I want to keep the budget around 1000, and there are very limited choice. Maybe I will start and thread about suggestions.
Gte, you have TWO problems. First is that you have about 130 more Watts of power than you'll need for your Zus. Second is that your poweramp has about 30dB TOO MUCH gain. Too much gain amplifies preamp noise (and the thermal noise inherent in the resistors in any attenuators) excessively and resticts volume-control movement. (At 12dB, your preamp does NOT have too much gain.) DIYaudio.com recently issued a newsletter about gain structure. I can't find it online; if you'll e-mail me at jeffreybehr(at)cox(dot)net I'll forward it.
Nelson Pass, with his FirstWatt amps, recognizes the general problem of too much system gain and solves it with one poweramp, the F4, with ZERO Voltage gain. Read about it at http://firstwatt.com/index.html . It has plenty of power for the Zus and looks to me like a great choice. .
I not saying what the problem is, I'm offering a solution. If he keeps the Zu speakers he should redo his preamp/amp. If he gets rid of the Zu, he just needs new speakers. Which is easier and less expensive to implement?
oNHWY61, The problem is`nt the Zu`s high efficiency(often a big plus). Again it`s not too much power or current, excess gain is a entirely different matter.Elizabeth uses very inefficient (84db) speakers and has the same issue. It`s gain folks.
It seems the gain of the amp is not a published specification. I can only see it inside the Stereophile review under measurement section.
As a rough approximation, you can calculate the gain by using the input sensitivity and output power numbers, and then adding a few db to the resulting number:
First, convert the 8 ohm power rating into volts, based on
P = (Esquared)/R,
where P is power in watts; E is the voltage corresponding to rated continuous power into 8 ohms; R is 8 ohms.
In this case, P is 150; R is 8. Therefore E = square root (150 x 8), or 34.6 volts.
Using the 1.5 volt sensitivity rating that was provided above by Dave, the voltage gain is 34.6/1.5 = 23.1.
Next, convert that gain to db by taking 20 times the logarithm of the voltage ratio:
20 x log(23.1) = 27.3db.
As I indicated, the actual gain will be somewhat larger than that number (in this case by 5db), because the continuous power rating will be lower than short-term power capability, and because of margin that is provided in the specs.
I would like to try the SET amp.... Does the requirement to have input impedance > 100k Ohm still apply?
Yes. That is a consequence of the preamp's output impedance characteristics. As for specific amp recommendations, you might want to research past threads to see what amps people have used with the particular Zu model, and/or start a separate thread on that question.
I can lower my DAC input so I can make the volume know of the preamp within a usable range. This is similar to if I lower the volume in iTunes. My question is, how would this affect the sound? Will I run into the bass roll off problem like using attenuator?
IMO reducing the setting of that volume control is a reasonable thing to try. The bass rolloff effect I described has no relevance to that. As Ralph (Atmasphere) indicated, the sonic effects of reducing the setting will depend on the specific design, and only you can make that judgment.
Gte357, I`m a huge avocate for SET amplifiers(particularly with your speaker`s 101db sensitivity) however power and gain are`nt the same. you can have a low wattage amp with very high gain and a high powered amp can have normal or low gain. You must also factor in the amp`s sensitivity, for example 300mv is very sensitive and 2v would be far less sensitive. Your current system simply does`nt need the gain of the active preamp. Thus direct source to amp or a passive preamp. If you want to keep your preamp you`ll need an amp with much less gain than your DNA1.
Sell the Zu speakers and get another speaker with lower, say mid-80s, efficiency. You'll get more of you're money back selling the Zus, they are a hot item compared to the McCormack amp. There are plenty of fine speakers out there that like an amp with power and current.
We have an amp that has only 23 db of gain. It works really well with ZU speakers too.
The problem you are having is classic- a DAC with too much output. I don't understand why DAC manufacturers do this- to me it seems like a fundamental misunderstanding of how power amplifiers work. There is not a power amp out there that needs more than 3 volts input, so why do you need 5 or 6V?
With that kind of output you have to attenuate the signal, either by passive control, digital volume control or something like the Rothwell attenuators. *All* of them rob the signal of musicality! With digital and passive controls, the higher you can run the control the better they sound (although for different reasons). So why force the user to turn things down so much??
Enough of my diatribe- you have gotten good advice from other posts here...
Wow, thank you very much for all the inputs. It seems all the parameters affects the gain, and it sounds like really my system is lacking synergy. And there is alot of technical stuff that I don't really understand, please excuse me if I ask something stupid.
It seems the gain of the amp is not a published specification. I can only see it inside the Stereophile review under measurement section. How stupid ...
Almarg, thanks for your insight about bass roll off with attenuator. I don't have the engineering background to understand the correlations between impedance and all those stuff, but I will take your words.
I really want to keep the PrimaLuan preamp. I don't have anything technical to back me up, but in my experience, the preamp has a bigger impact to the sound then the amp. And I like how PrimaLuna sound, so, I likely will keep it.
I will try to connect the DAC directly to the amp, but I will missed the PrimaLuna sound.
About the option to lower the gain of McCormack, I think I won't go that path also. It seems I will need to send the amp to Steve, it is kind of a hassle. Also, my new Zu speaker won't need such high current, so, if it is not compatible, I may sell it out and get something else.
As people can see, my Maverick DAC has a volume control as well. So, I can lower my DAC input so I can make the volume know of the preamp within a usable range. This is similar to if I lower the volume in iTunes. My question is, how would this affect the sound? Will I run into the bass roll off problem like using attenuator?
Another option is to get another amp. I would like to try the SET amp. If I want to keep the PrimaLuna, what parameters should I pay attention to? I know most of them are pretty low power, but as said, power is not the real problem. I don't think they publish the gain info. Also, does the requirement to have input impedance > 100k Ohm still applies? Maybe more straight forward, what is your recommendation?
04-29-11: Davehrab The PL3's output voltage is 5 volts as measured in a Stereophile review and way to much output for the DNA1's input stage.
With due respect for your well intended comments, I believe you are misinterpreting that spec. That number represents the output voltage at which the onset of clipping occurs, as indicated by a significant rise in distortion. The higher that number the better, everything else being equal. The actual output voltage at any instant of time will equal the input voltage multiplied by the gain that is provided by the preamp at the volume control setting being used (12db being the gain corresponding to the maximum setting of the volume control).
You can put a 10db attenuator at the amp's input or just remove the PL3 and drive the DNA1 from the Dac ... which has Tube output and a volume control.
If the PL3 is used, putting a 10db attenuator at the amp's input won't work well. Bass rolloff will result, as I indicated in my previous post. It also won't be a sufficient amount of attenuation.
Good point about the volume control on the DAC, though. Assuming it is the D1 model, I note that it also includes source switching, for both digital and analog sources. I don't know what its output impedance is, but if it is low enough to work well with an in-line attenuator, perhaps ditching the preamp AND putting a 10db attenuator at the amp inputs would do the trick. The OP might want to ask the DAC manufacturer what its worst case (maximum) output impedance is, across the audible frequency range.
If it were me, though, I would seriously consider Herman's suggestion of a 300B SET amp, or other low powered tube amp.
Nothing to add to the gain comments, I agree you simply have waaaaaaay too much.
Your speakers are begging for a low power SET amp like a 300B. Keep an idea on the classifieds and you can find a very nice 300B amp in the $1,000 range. A passive pre and an SET is my recommendation.
You can essentially nullify the gain of the preamp (reducing it to 2db) by placing a pair of 10db Rothwell Attenuators, or similar devices that are available from other manufacturers, at the preamp inputs.
However, to obtain an adequate overall reduction in gain, you would have to place an ADDITIONAL 10 or even 20db of attenuation at the power amp inputs, and there would be a problem doing that.
According to Stereophile's measurements of your preamp, its already very high output impedance of 2.7K at mid and treble frequencies rises to 11.5K at 20Hz. That rise will result in a significant deep bass rolloff when driving most or all readily available passive attenuators. (I've measured the input impedance of my Rothwell's as being about 33K, which is much too low to be driven properly by a preamp having that kind of output impedance).
As I see it, the fundamental problem is that your power amp is much more powerful than what is required by 101db speakers under typical conditions, and although (as was said above) power and gain are two different things, they generally have a significant degree of correlation. I would suggest selling the amp and replacing it with something that is less powerful and has lower gain. Having to pay for fewer amplifier watts may also allow you obtain better sound quality per amplifier dollar.
If you do that, be sure to choose an amp having high input impedance (ideally 100K or more), to be a proper match for the PrimaLuna.
Your DNA1 has an input sensitivity of 1.2 volts .. which means a 1.2 volt signal will drive the amp to it's rated output (150 WTs)
The PL3's output voltage is 5 volts as measured in a Stereophile review and way to much output for the DNA1's input stage
The PL3 is over powering the DNA1 input stage and you can't use all the volume control available in the PL3 as it only takes 1.2 volts to drive the amp to max output
You can put a 10db attenuator at the amp's input or just remove the PL3 and drive the DNA1 from the Dac ... which has Tube output and a volume control
The Dac's 2 volt output is much more compatible with the DNA1's 1.2 volt input sensitivity
Unless you need the PL3 to switch other sources ... take it out as you already have Tube flavor in the Dac
Wouldn't hurt or cost anything to give it a try ... Ditch the PL3 to and give it a listen
Given the exceptionally high gain/amp and very sensitive Zu speakers, you have the ideal setting for a passive preamp(high quality). Your system needs no additional gain at all. GoodLuck,
Couldn't find the Vout spec (or any others) on the Maverick DAC. If it's over 2V, that could be the problem. On a Monarchy DAC, it had an internal dip switch for 3V/6V output. High output is typical for DAC/preamps with a volume control.
The McCormack DNA-1 does have a pretty high gain but still a sweet sound. Even its little brother the DNA.5 Deluxe that is really musical has a gain of 29dB.
At one time I had a McCormack DNA-1 Deluxe, with a McCormack TLC-1 Deluxe preamp with signals being fed to it from a McCormack DAC-1 and an Oppo BDP 83 as a transport. Speakers were a rebuilt pair of KEF 104/2s that have a 92 dB efficiency. The room they were in was on the small side and the sound would get really loud with volume a little past the 9 o'clock position. The soundstage was great and the sound was crisp though.
I agree with some of the posts on top. You may have to modify or change your preamp to one that has lesser gain or your source to one that has a lesser gain or warmer sound. I say keep the DNA-1 but I have a heavy bias toward McCormack gear.
Less power output won't solve your issue - gain is separate from power. According to Stereophile, the DNA-1 has a gain of 32dB! That's really high, and a big part of your problem. I would investigate either a passive preamp or, if you like the Primaluna, talk to Steve McCormack (http://smcaudio.com/) and see if he can cut down the gain on your DNA-1.
The problem will definitely get worse with the Zus. I own Druids, and had to take some gain out of my power amp to make the system work.
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