2. amps-preamps
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Finding the right tube preamp (input values) for Mccormack DNA

Forgive me but how do I determine the input sensitivity on any particular tube preamp? 

I have tried to figure it out some manufactures are easy and label it but some have a lot of values and with my limited knowledge of values and current specs I find it hard to figure out which is a good match.

I have a Mccormack DNA-1 Deluxe and am looking to add a tube pre. I have seen the likes of Audible Illusions, Conrad Johnson, BAT, and others who are good matches but I would like to possibly see about modern gear for a good match. Like Jolida, Rogue and Odyssey to name a few. 

What are the specs I am looking for to see if they are a good match? I have read the Mccormack has input value of 10v.

Thanks,


db
photodusty
9 responses Add your response
photodusty OP
100 posts
 
I should add I am looking for Preamps under $1500. I also have NHT 3.3 speakers.

db
yogiboy's avatar
yogiboy
5,701 posts
 
The input sensitivity of the DNA-1 is 1.2 volts and input impedance of 100k ohms. Any preamp should drive that amp with no problem!!
gdnrbob
4,447 posts
 
@yogiboy ,
+1
When in doubt, call Steve at SMcAudio. I think they will confirm Yogiboy's advice.
FWIW, a used Atma Sphere UV-1 would be a nice match.

B
photodusty OP
100 posts
 
Thanks @yogiboy ....I have read that some tube preamps would have too much gain for the Mccormacks due to the high input...... hmmm

@gdnrbob I will be in contact with him this week. Thanks,


db
lowrider57's avatar
lowrider57
5,417 posts
 
You must take the preamp gain into consideration. In most cases it's not an issue, but CJ preamps have high gain. Find the gain of the actual preamp you're interested in and ask Steve McCormick.

soix
9,571 posts
 
@photodusty -- I think the problem with tube preamps is more with Steve's amps with his higher-level revisions (A, Gold, Platinum, etc.) rather than the stock or Deluxe models.  If memory serves, input impedance on models with certain revisions was quite a bit lower than 100 kOhms, but this may vary by model and revision level.  As mentioned earlier, you should be fine in most cases with your amp. 
hifiman5's avatar
hifiman5
1,832 posts
 
@soix I believe you are mistaken.  I asked Steve Mc about input impedance and was told that it remains 100k after his SMc Audio upgrades.
photodusty OP
100 posts
 
See, now even more confusing. 

So when looking at a preamp, what values what am I looking for?...some say 10v some say 100K some say 28db volume.....etc....


db
atmasphere's avatar
atmasphere
11,841 posts
 
You want a preamp with plenty of overhead, so at normal volumes it makes no distortion. That might be that 10Volt figure, although IMO that's a little low.
Since you have NHTs the gain might be handy although most tube line sections won't have 28 dB- 15dB is more comon. The input impedance of your amp is 100K (single-ended) and so nearly any tube preamp can drive it.

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