A tale of Gain.

DaveyF

Well-Known Member
Jul 31, 2010
6,129
181
458
La Jolla, Calif USA
Most of the forum members most likely already know that matching the gain between your preamp and your amp is pretty important. I hadn't realized how important until a few days ago. On my amp, I have the ability to change the amp's gain setting between 26db and 32db. I had been using the higher gain setting of 32db for some time and after reading up a little more on the subject, decided to change the setting to the 26db setting. Apparently this is the standard gain setting that most ss amps are delivered with. Since I use a tube preamp which can swing upwards of 7volts, the 26db gain setting is definitely preferable. The result was back ground noise from the amp was majorly reduced and the whole system has taken on a much greater sense of ease. Which brings me to my point, IF you have the ability to change gain settings on you amp, it is very well worth while adjusting the settings to see what the amp prefers. I noticed that the preamp is a little more in the 'sweet spot' on the volume control. OTOH IF you do not have the ability to change the gain setting on your amps input, then a very careful matching with the preamp is probably warranted. I question how many a'philes do not have this seemingly trivial factor taken into account, I know I was one who benefitted greatly by the correct matching.:D
 
Last edited:

LL21

Well-Known Member
Dec 26, 2010
14,411
2,509
1,448
Thanks. I hAve 26db pre and 31db amp...fortunately silent unless standing 3 inches from tweeter...and if I put on new tubes then u still have silence. Is there anything I should be considering here Davey?
 

DaveyF

Well-Known Member
Jul 31, 2010
6,129
181
458
La Jolla, Calif USA
Lloyd, try changing between the two. Preferably while playing music if possible. One setting will be clearly 'right'. The whole system takes on a much better sense of ease and greater dynamics. BTW, I suspect that we are lucky that the amp has the ability to change gain settings, I'm not sure that many do; which would lead to the probability that the amp isn't in the 'sweet spot'.
 

Steve Williams

Site Founder, Site Owner, Administrator
No typo as far as I can see either but thanks for bringing it to everyone's attention Bob

Back OT. Davey can you and/or would you change the settings on your amp playing music on the fly. I'd kind of worry about smoking something
 

DaveyF

Well-Known Member
Jul 31, 2010
6,129
181
458
La Jolla, Calif USA
No typo as far as I can see either but thanks for bringing it to everyone's attention Bob

Back OT. Davey can you and/or would you change the settings on your amp playing music on the fly. I'd kind of worry about smoking something

Thanks Steve, that's how I was able to do the 'AB'. My amp has this ability, I'm not sure if others would however...so precaution is the key here. Alternatively, probably safer to mute the input signal and do the change under the mute.
 
Last edited:

mep

Member Sponsor & WBF Founding Member
Apr 20, 2010
9,481
17
0
I don't think you should ever change the gain setting with the amp on. You are asking for trouble.
 

DaveyF

Well-Known Member
Jul 31, 2010
6,129
181
458
La Jolla, Calif USA
How many of us have the ability to change the gain settings?
The procedure needs to be followed according to the amps instruction manual...that is the safest.
 

mep

Member Sponsor & WBF Founding Member
Apr 20, 2010
9,481
17
0
Most amps that I'm aware of do not have provisions for changing the gain. There are some that do of course, but they are in the minority as far as I know. However, lots of preamps have switchable gain. Both of my Krell preamps (KBL and KRC-HR) have a switch on the front to increase the gain. With the KRC-HR, that gain is switchable from the remote. When I listen to LPs, I do switch in the extra gain.
 

Steve Williams

Site Founder, Site Owner, Administrator
I don't think you should ever change the gain setting with the amp on. You are asking for trouble.

I tend to agree with Mark here Davey


FWIW I can't change the gain setting on my amp
 

Mike Lavigne

Member Sponsor & WBF Founding Member
Apr 25, 2010
12,467
11,363
4,410
two issues typically affected by amp gain changes;

--volume control in the preamp. they typically have a sweet spot. and also the degree of fine adjustment can be affected by changing the gain on the amp.

--any source, particualrly any phono stage noise level. and it can work both ways. you can be overdriving the phono stage because your amp gain is too low.

it's all an issue of overall balance.

if it sounds better then it is.
 

DaveyF

Well-Known Member
Jul 31, 2010
6,129
181
458
La Jolla, Calif USA
I tend to agree with Mark here Davey


FWIW I can't change the gain setting on my amp

Not sure what Mark says, as I have him on ignore:D.
As my preamp is a tube preamp, and I am using a ss amp, this is where the discrepancy arose. The tube preamp has a considerable gain, as it turns out too much for
the higher gain setting on the amp. Like Mike L stated, it's very much a matter of balance, which is my point in this thread. When it's right, the sound will be better.
I suspect that IF one owns the same make of amp and preamp, then likely the designer has taken this issue into consideration with his gear, OTOH, IF like me you own
a different make of preamp and amp, then this is a consideration. Particularly if one is using a tube preamp and a ss amp. Since I am unaware of any tube preamps that have switchable
gain settings, then this issue may be a factor.

Once again, it is obviously best to observe the instructions in the amp's user manual as to the procedure for gain change.( IF this is even possible).
 

mep

Member Sponsor & WBF Founding Member
Apr 20, 2010
9,481
17
0
Cool that DaveyF has me on ignore. My Counterpoint SA-5.1 which was a true tube preamp had switchable gain. Switchable gain is much more common on preamps than power amps. As for what Bruce said, he is correct that you will increase the gain if you use balanced connections from preamp to power amp. However, lots of people don't have that option. Davey's preamp for example does not have balanced outputs. I don't know what he is using for a SS amp. Last I knew he was using the ARC D-70 MKII tube amp.
 

microstrip

VIP/Donor
May 30, 2010
20,806
4,698
2,790
Portugal
Sometimes you must also consider that speaker sensitivity in the equation. Most of the time, although we have a few guidelines (matching an high gain amplifier with a noisy preamplifier will probably be a mistake), only by experience we will know if the gains are adequate.

And even when the preamplifier or the amplifier has switchable gain most probably you will find that it sounds better in one of the positions - and Murphy law probably will assure that the best sounding position is not the adequate for your system!

My usual preference is to use the same brand of preamplifier and amplifier - usually the manufacturer takes care of these aspects. ;)
 

microstrip

VIP/Donor
May 30, 2010
20,806
4,698
2,790
Portugal
Cool that DaveyF has me on ignore. My Counterpoint SA-5.1 which was a true tube preamp had switchable gain. Switchable gain is much more common on preamps than power amps. As for what Bruce said, he is correct that you will increase the gain if you use balanced connections from preamp to power amp. However, lots of people don't have that option. Davey's preamp for example does not have balanced outputs. I don't know what he is using for a SS amp. Last I knew he was using the ARC D-70 MKII tube amp.

There is a lot more on using single ended or balanced connections than just the 6dB difference in gain. Needing to choose the operation mode just because of the gain is 90% of times a poor compromise. Most equipment having balanced outputs sound better in balanced mode, as they anticipate the common mode rejection of the balanced input stage.
 

LL21

Well-Known Member
Dec 26, 2010
14,411
2,509
1,448

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. This is THE place where audiophiles and audio companies discuss vintage, contemporary and new audio products, music servers, music streamers, computer audio, digital-to-analog converters, turntables, phono stages, cartridges, reel-to-reel tape machines, speakers, headphones and tube and solid-state amplification. Founded in 2010 What’s Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals, we enjoy learning about new things and meeting new people, and participating in spirited debates.

Quick Navigation

User Menu

Steve Williams
Site Founder | Site Owner | Administrator
Ron Resnick
Site Co-Owner | Administrator
Julian (The Fixer)
Website Build | Marketing Managersing