2. amps-preamps
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Tube pre, SS amp incompatibility, which amp 2 use?

I wanted to see how a tubed pre-amp would sound in my system so I purchased a Jolida Music Envoy pre-amp to mate with my McCormack DNA-1 amplifier. When I put the pre-amp in the system it would not work. After talking to Jolida, where Jerred helped me try various things, we came to the conclusion that they were just not compatible, since the Jolida works just fine with an old Marantz I have. The Jolida has in output impedance of 600 ohms. The McCormack has an input impedance of 100K ohms.

Next I emailed Steve McCormack asking his opinion, and he also gave various reasons for the failure, but after letting him know what was done in an attempt at making them work together, he also stated it may just be a compatibility issue.

Now I would like to get a different amp to try with the Jolida, but am a little weary of purchasing another just to find out that for one reason or another it will not work.

Since this is just to see if I would like what I hear, I don't want to put a lot of money into it. My speakers are 6 ohm Gershman Acoustics Sonograms and are 89db efficient, so I'm looking at an SS amp with good power for less than $1K.
Does anyone know of any amps I can look into that DO work with the Jolida, knowing for sure, that they will be compatible?
abucktwoeighty
almarg's avatar
almarg
9,670 posts
 
Unsound, note my earlier statement:
Basically, the very high input impedance of the DNA-1 may be bringing out a design issue in the preamp. The Marantz presumably has a much lower input impedance, perhaps 47K or less, which does not bring out the issue. The very extended low frequency bandwidth of the DNA-1 (specified as 0.5 Hz) is presumably also a factor that contributes to bringing out the issue, as explained in Ralph's (Atmasphere's) posts.
The problem is with the Jolida, but if there are means by which the Jolida and the DNA-1 can be made work together, and which produce results that 280 finds to be sonically satisfactory, there is no need to replace it.

Best regards,
-- Al
unsound
7,353 posts
 
Thanks Al. I can't explain why I missed that in very first sentence. Silly me.
abucktwoeighty's avatar
abucktwoeighty OP
1,079 posts
 
I'm very happy with the Jolida in the system. I'm waiting for a set of Rothwells to replace the passive volume control. I also bought some different 12ax7's to try out. The ones supplied with the pre-amp roll off the upper end. It's quite a difference having it in the system. Imaging is amazing and the soundstage has widened. Now I just need the correct flavor of tubes and I'll be set.
As far as the problem is concerned, I'm very happy with the current remedy.
abucktwoeighty's avatar
abucktwoeighty OP
1,079 posts
 
This is a follow-up. I received the Rothwell attenuators. I removed the passive volume control and placed the Rothwells in place. There was a one time driver excursion outwards along with a small popping sound. Then all was well. With the passive volume control there is no excursion. I am going to leave the passive volume control in place as this is doing a better job than the Rothwells.
atmasphere's avatar
atmasphere
12,117 posts
 
Abucktwoeighty, do you have a Digital Volmeter (DVM)? If so you might want to measure the voltage at the output of the Jolida with the volume turned down. If its anything other than 0volts, you have a problem that should be fixed.

If the preamp employs paper and oil coupling caps, they can sometimes develop electrical leakage, resulting in a slight DC voltage at the output of the preamp. This would cause the behavior you have described. I have no doubt that the insertion of a passive control or an attenuator is degrading the sound; IOW its worth pursuing this.
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