Preamp has too much gain


Hi.
This is my first post here. I have a Consonance Reference 1.1 preamp that has too much gain. Is there anyway I can reduce the gain without any loss to the sound and does any member know how I can go about purchasing a schematic. I try to fax them, but their tel. number is not in service.
electra
A quick and easy method is to install an in-line attenuator between your pre-amp and amp. There are typically classified ads here on AudiogoN for a Rothwell 10bd in-line attenuator. I've never used them, but the subject comes up often and I've read that they don't seem to have a negative impact on overall sonics.

Personally, I would prefer this method to modifying the circuit. I wouldn't want to do anything to the unit that may damage it or lower its resale value.

Enjoy,

TIC
I have a Consonance Reference 1.1 preamp that has too much gain.

I'm assuming by this you mean it is too loud with the volume barely turned up, but your assessment of the problem is not correct since you never use the gain that the preamp has. The stated gain of the pre is with the volume all the way up, but you don't have it all the way up (the preamp is attenuating the signal all the time instead of amplifying it) so the problem is it doesn't attenuate enough and/or the steps are too big (and here is the important part) for your combination of components.

It is normal to blame the pre because that is where the volume control is, but that isn't the correct analysis. You need a source that puts out less voltage, or a pre with more attenuation, or an amp that has less gain, or speakers that are less efficient, or some combination of these.

In line attenuators as suggested is one approach, or find components that go together better.
Very easy to fix, just need couple of high-quality resistor to construct a voltage divider.

Assuming your preamp has an input impedance of 100kOhm, then, to reduce the gain to 1/3, you can insert a 200kOhm resistor in series to the input RCA.

The gain will be reduced by 100k / (200k + 100k) = 0.33x, i.e. 1/3 in this example.

You can also use a high quality variable resistor, such as a Bournes pot then you can adjust the gain with a screw driver.
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Wow, answers to a question I didn't even know I had. I have the same pre as Electra and always wondered why I could only turn it up to about the nine oclock position, (with zero being about 7 oclock), without it being too loud for your average listening session. My source is a Sim Audio Moon Eclipes, my amp is a Redgum, forget the model but it's about 150wps, speakers are Osborn Grand Monument Refs. Am I going to get a better/ different sound by doing some of the changes you have recomended, or does it really matter where the dial is set?
One of the few things that designers will agree upon is that the closer you operate to maximum volume then the better the sound. Volume controls always take away. The ideal system would have an overall gain (source + preamp + power amp + speaker efficiency) that plays a particular recording at the ideal volume level with the volume control all the way up.

I’m not talking about loud volume, but the maximum that a system will allow. The problem is that the level from recordings varies widely and we want to listen to different types of music at different volumes, so the maximum volume is often too loud.

If you consistently have the volume control way closer to the minimum than the maximum then the volume control is choking some of the life out of your system.
The electronics should be run at the highest possible gain, at a given supply voltage, where feasible. For example, if the line stage is designed for 20dB of gain, and you run it at 5dB, the THD will go up tremendously, and the circuit may even become unstable. The higher gain also gives you the best S/N ratio.

It's the right way to pad down the signal level, then to lower the gain. The noise in the system is typically 'White', so the less gain, the less useful dynamic range.
I also had a gain issue. I installed rothwell 10db attenuators between my cd player and pre-amp and that solved the problem.

Chuck
The electronics should be run at the highest possible gain, at a given supply voltage, where feasible.

I don't understand. How would you lower the gain of a preamp without major reconstruction? THD comes from operating an active device in a non-linear manner. The operating point (bias) of the active device determines where you are on the curve and this isn't really related to gain so THD really isn't related to gain except in the sense that it will increase if you allow the signal to become so large it swings into the non-linear portions of the device's curves. It's a bit more complex than that since bias and operating points can affect gain but that's the basics. Maybe I'm missing something here.

Mark Levinson superb 326S preamp allow you to adjust the gain of the inputs from 0, 6, 12, and 18db. So, depending on your amp and speakers you can match the gain that brings out the best of your source. Your room acoustics will also play into it. With my McIntosh amp, the 12 db. gain settings sounded the best. Now I have a Mark Levinson amp and the 0db setting is very enjoyable, imaging is stable and in place and solid, bass is tighter, brass and such as the correct bite. Vocals sound so real you can see the artist face in front of you. the other settings sound good, will give you more upfront bass and such but you lose that coherency of the overall sound. Things just sound right at 0db, I like 12db if I want to have a bigger fatter sound with more upfront bass. The 326S at 0Db gain setting is just sweet, classy sounding, sounds like a gateway to the recording. Also, the way the ML volume control is designed it adjust to the gain setting so the old ways of thinking that a preamp gain should be low enough to where you turn the volume control almost all the way up, ML is way past that old way of how volume controls were designed back in the day. The best preamp I've owned tube or SS in 40 years. 

SPL Phonitor 2 Pre/HP also allow gain adjustments and is transparent zero coloration, you hear the actual source material. It is studio equipment. 

OP: 

Can you give us a little more detail?

Is the amp too loud or do you have too much noise?

If the amp is too loud a passive attenuator would work.  Having said that, there are many examples of preamps with too much gain, and therefore too much noise.

Which is you?

 

Erik

I had a preamp with a Goldpoint stepped volume pot with too much gain and installed Takman resistors on the pot and fixed the problem.

In-between the pre and power amplifier, insert another passive preamp ( without power), that let you adjust anytime in the future.

 

LOL, maybe he did 16 years ago but now this thread came back to life I need some help with my Audio Research LS1 Line Stage's gain control.

I am streaming Eversolo DMP-A6 into the LS1 at line level.  A6 is using volume bypass but it is so loud that I can use only 1-2 clicks on the LS1 gain level knob.

I then use the CD inputs on the LS1 because it lowers the input by 10db and now I can use 3-4 clicks on the gain knob but it is still far below the 9 o'clock position. Reading from above I now know this can impact the sound quality.

I do have the option of turning the volume bypass off in the A6 and it can lower the volume coming out of the streamer.  However, that is a digital volume control and my understanding is attenuating it will impact the dynamic frequency and is not ideal.

The LS1 user manual did mention that doing some de-soldering "gain change connection" on the circuit board can reduce all line inputs by 6 db.  Is this the best way to go or is there an easier way?

The power amp is a Classe CA-2200 (200W x 2).

Thanks for any help on the subject!

 

 

 

 

 

 

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