Gain Question

I have just noticed that there is a Cary CAD200 for sale here on the Gon. It is a SS unit that puts out 200 watts and 27db of gain. Might be an interesting pairing with my SLP05. I'm interested in opinions from more knowledgeable people on this possible pairing

Call Herron just to make sure it is ok to do this.

Yes give that a try,it might be the problem.

phono preamp uses 4 12AX7's and 1 12AT7. Are you saying I should try a 12AX7 in the 12AT7 spot?

If phono preamp uses 12at7 type tubes replace with 12ax7 this will give you 40% more gain,I think it might solve low gain problem.

John

Unfortunately when I checked out the Clearaudio carefully, the stylus was bent so without a retip, don't think I can try this option. HOWEVER see my next post about another avenue I am considering

Summed up very well Markus1299. Don't be hard on yourself though, we all learn as we go through this journey together. It's not the destination, but the journey itself which enthralls us. (I take it that means the Clearaudio Virtuoso didn't work out?).

If you go looking at another cartridge, you may find this thread helpful in understanding the difference between the two standards in which cartridge output is measured. Using this formula you can compare cartridge specs as apples to apples, instead of apples to oranges.

Cheers,
John

You know, as a fairly new audiofile enthusiaist, I have learned a valuable lesson here. Do your homework well before purchasing components that you think will match up in a system

You don't "need" to run the MM into the MM input. You could try it into the MC as long as the phono stage has enough headroom. It would not be ideal since the MC input wouldn't have the capactive loading that the MM wants to see so not a permanent fix but an interesting experiment that can do no harm. As long as it doesn't clip, or maybe even if it does a little it would answer the question of whether or not you have enough gain prior to the amp. If you use the extra 20dB of the MC input AND it doesn't grossly clip AND that gives you the volume you are looking for then you would know the amp is capable as long as it gets a bigger input signal. If it is loud enough then you need to get the gain somewhere else. You're not going to find a phono stage with significantly more gain so that leaves a higher gain preamp if you want to keep the amp, or an amp with higher sensitivity, or a combination of the two.

Many preamps have gains over 20dB which looks to me to be the ultimate solution as long as 120 watts is enough to get the speakers where you want them, and I suspect it is. . You could also search the classifieds for a fair price on a preamp with 20+ dB of gain and try it. You can sell it if it is not the sound you want but that would also answer the gain question.
.

Actually, I don't know that it will get you that much more gain, considering you will need to run it through your MM input and not your MC input of your Herron. The cartridge will put out a higher signal, but your phono stage will lose about 20 db of gain switching from MC to MM. It could help a little overall though, it's certainly worth a try.

Cheers,
John

I just found an MM, Clearaudio Virtuoso Wood cartridge from a table I purchased that is long gone. I think I'll give it a spin to see how it compares. Should be interesting. I'm sure the gain will be there but sound quality???

The vinyl sound is enjoyable at present but every once in a while there is that specific cut that you would just like to boost a little bit and I don't have that option.

Which prompts a further thought. Records are cut at different levels. If you sense that those specific recordings are cut at lower than average levels perhaps a gain increase (via a different cartridge, or tube rolling, or some other means) would help, without changing to a more powerful amp.

Contrasted with that, though, would be the situation where you want to increase the volume setting due to the recording having very wide dynamic range. An example being well recorded symphony orchestra, where the average level may be fairly low, but brief orchestral peaks very high. If that is the type of recording you find yourself wanting to turn up higher, more power may be called for, to prevent clipping on the peaks.

Good luck!

-- Al

the mm vs mc thread can be found at
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1200430667&read.

consider that the SLP-05 has a rated nominal output level of 2V, and is presumably designed to be compatible with your CAD120S. That would suggest that the unspecified input sensitivity of the CAD120S is significantly less than 2V, to assure that the SLP-05 can drive it to max power.

People are making assumptions about the input sensitivity of your power amp. These assumptions could be right, or they could be wrong. You should contact Cary and find out what the actual spec is. This will determine whether your preamp is capable of driving your power amp properly. This is a must know fact if you are to logically pursue any solution.

FWIW, HO mc carts are "generally" a poor compromise. To get the higher output, you need more windings on the coil, whoch makes it less responsive. You might want to check out one of the MM carts that are discussed on the MM vs MC thread that Raul started. You might even ask him to recommend a cart that matches well w your arm/tt.

Thanks Al for sorting this all out for me and, others that are much more knowledgeable than myself, for adding significant things to look at in my system. The vinyl sound is enjoyable at present but every once in a while there is that specific cut that you would just like to boost a little bit and I don't have that option. Was kinda lookin for an easy tweek but doesn't look like thats going to happen. Maybe a cart with higher output would help. I'll have to experiment, thats half the fun.
Thanks guys!

From John Atkinson's measurements of the SLP-05:

The SLP 05 offered slightly different maximum gains from the figures specified on Cary's website. However, the specified gain is different on the Specifications page—10dB single-ended, 8dB, balanced—from what it is on the Literature page—12dB. In a telephone conversation AD had with Cary's Dennis Had, Dennis said that the 10dB/8dB numbers were a misprint, the real numbers were 16dB unbalanced and 12dB balanced. With both input-level controls and the volume control at their maximum settings, I measured 15.3dB for unbalanced input to unbalanced output and 13.8dB for balanced input/output. The difference, perhaps, is due to inconsistencies in the tube gains. Usually, such differences would have been minimized by negative feedback, but the SLP 05 apparently doesn't use any negative feedback.

This suggests two things to me:

1)You may be able to change the gain significantly by tube rolling.

2)However, there is no point in doing so because you most likely can already drive the amplifier to the clipping point, considering that the present gain is most likely several db higher than the 10db I used in my earlier calculation (which reflected 1.9V into the power amp).

Also, consider that the SLP-05 has a rated nominal output level of 2V, and is presumably designed to be compatible with your CAD120S. That would suggest that the unspecified input sensitivity of the CAD120S is significantly less than 2V, to assure that the SLP-05 can drive it to max power.

All of which seems to reinforce the comments Herman and Greg offered about needing more power (which would also provide more gain, assuming input sensitivity remained comparable). A step-up transformer obviously will not help in that regard; might result in overload problems as has been indicated; might degrade the sound quality that you are presently happy with; and would result in your having to address and experiment with a lot of complex interrelated variables that sut's inevitably involve, if sound quality is to be fully optimized.

But there is another significant constraint involving increasing power. Your Harbeth's are rated to handle a maximum of 200W on program peaks (their continuous power rating is probably considerably less), and 200W is only about 2db louder than 120W.

Note to John: Thanks for pointing out that the balanced output gain of the SLP-05 is spec'd at 2db less than for the unbalanced output. Actually, I had noticed that, but I was envisioning that the power amp's balanced input MIGHT have a 6db higher sensitivity (lower sensitivity number) than the unbalanced input.

Markus: So I'm not sure what the answer is, but those are the thoughts that I can offer at this point. Ultimately, you are constrained by the peak spl capability of the speakers.

Regards,
-- Al

Markus, methinks Hermann has a point about more power; your amp maxes out at around an extra 19dB. So, on paper your top undistorted amplitude with the 40.1 would be around 103-4dB.

Question is, can the 40.1 take many more Watts? If you get, say, a 250W/channel amp, on paper you'd get something like 110dB peaks... not bad -- i.e. twice the top spl you're getting now.

Your preamp is a low gain design. I find it interesting that the Cary website doesn't provide input sensitivity specs. It would help to determine where the gain mismatch is located. Either between the phono/preamp or the preamp/amp. Changing to a more sensitive speaker may correct the symptom(s), but won't cure the problem.

According to their website, the Harbeth 40.1 has a sensitivity of 84db/1W/1M.

You could use a SUT, but it would probably overload your MC input on your Herron. You could however run it into the MM input. If you got a SUT with 30 db of gain, and ran it into your MM stage with a gain of 43/48 db, you'd have a total of 73/78 db. This could give you as much as 12 db more gain before the preamp.

Cheers,
John

So an amp with more power would solve the problem? My 40.1 Harbeths are at 86 db efficencey so I can see that as a problem but really love the sound of these Brits. Power on the top end seems to be the answer.

Al, actually his Cary SLP-05 preamp has 10 db of gain single ended but only 8 db of gain balanced. I know, this seems odd.

Do you want it to be louder? If not you actually get the best sound with the volume control at or near maximum. If you don't want it to go louder you are in an ideal situation.

Your phono pre has quite a bit of gain so I suspect a step up will overload it. You need to fix it elsewhere.

I trust Almarg's math so if you do want it louder you need some more oomph from the amp. Since you are getting enough gain to get close to 2V into your amp if you want to go louder you have to get an amp that can get more power out with that input. Your low efficiency speakers simply need some more power.

Almarg,

I really hate to do this but what about using a step up. Any experince doing this? I see an Ear step up for sale here and I'm considering it. I just hate to introduce a whole nuther device with it's connecting cables ETC. What are your thoughts? Thanks for your response.

66db corresponds to a voltage gain of about 2000. 10db corresponds to a voltage gain of about 3.2. So 0.3mv from the cartridge will result in about 0.3 x 2000 x 3.2 = 1.9 volts into your power amp. That is roughly in the general area of input voltage that most power amps require to reach full power.

Speaker efficiency is also obviously a factor in all of this.

Those numbers reflect the volume control being set all the way up, so what you are finding is understandable and probably can't be fixed without a component change, or the addition of a component between preamp and power amp that would provide additional gain. Unless you are presently connecting preamp to power amp unbalanced, in which case a balanced connection may provide more overall gain. But looking at your system description I suspect that you are already connected balanced.

Regards,
-- Al

You can either get a cartridge with higher output, get a phono stage with more gain, or get a preamp with more gain OR some combination of the above.
Actually, there are two other options, get more sensitive speakers and/or get a more sensitive amplifier(s).

That's the only options I can think of for you to 'fix' this.

Cheers,
John