I don't use MC on a Chinook but you could start with these questions: What gain setting are you using now? I believe it does from 45dB to 65dB gain. If you are using max gain now, how much volume are you using to get where you need to be etc?
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should work fine. I have exact same phono pre.
also have the ART-9 and lower output LOMC carts; Benz LPS, and Madrigal Carnegie One which are both around 0.2mv output levels.
You will need to move the gain switches up to the highest setting.
Have been using RCA 6922s and Holland Bugle Boy 6DJ8s in mine.
If you want to drop the noise floor further, replace the TL082 devices with sparkos labs discrete devices; SS3602 parts... No soldering required, a plug in replacement
To answer first question:
I am using 60dB of gain on the Chinook for my 0.5mV output ART9. On my Bryston BP25 / 4BSST amp setup, I listen between 8:00-11:00 on the preamp.
I have the first version of the Upscale Audio SE. So in only has the 45dB, and 60dB gain settings. I could send it in to Manley to have the additional two added. Maybe 55dB, and 65dB. Is this probably needed for a 0.25mV cart?
As for the Sparkos labs devices; it seems they make discrete opamps. Looking inside the Chinook, I see three TL082 opamps; one per channel, and one on the PSU side, are you talking about all three? Are the ones on the channel side used for input? A review I had read stated they were not in the signal path, but rather used to bias the JFETs. I have seen a similar idea in Kevin Gilmore's designs. Did you notice a significant difference?
The nice thing about the 4BSST is that you can change the input sensitivity to 1 volt. You will need approximately 72db of gain to drive your amplifier to full gain using the 1volt input setting. The Manley can provide 60db of gain coupled with the Bryston's line level gain of approximately 15db, therefore, you will have a total of 75db of gain available. You will be fine.
Chakster- I do see other Airy models on Audiogon, but they're far more than the ~$1100 I can get this one for locally. The Ultimate seems to go for ~$2200 off demo? Is it that large a difference in sound?
Lewm- I have an SE, but not the SE MkII, so no 65dB setting. :/
brf- Good point, I had forgotten about this. I use balanced inputs off of my BP-25, so I am using the lower gain setting currently. I presume this would result in slightly more noise? Possibly less than if I had the Manley updated with the +65dB setting though?
tre, I am getting a bit confused here. I gather now that your cartridge drives a Chinook which in turn drives a Bryston linestage with an additional 15db of gain after the phono gain. You've got gain to spare, even if your Chinook itself only supplies 60db max. I am using the Steelhead as a full function preamplifier, so that the total phono gain in my system is whatever I set on the Steelhead. At the max of 65db, I have ample gain with the AT ART7. You've got 10db more gain than I do at your disposal. Of course, keep in mind that the input sensitivity of your amplifiers and the efficiency of your speakers also play a vital role in determining how much gain you need.
Now for my area of confusion: Did you say that you are using the balanced inputs on your Bryston? But the Chinook is single-ended, so how does that help, unless the Bryston has a circuit or a transformer at its line input that converts the SE to balanced? If the system were true balanced, using the balanced mode will result in less noise, not more noise. But as it is, I don't know if you'll have any benefit from the balanced inputs.
I never tried the opamp in the power supply, just the two on the input circuit. but having said that, the third may make a difference too.
The other area on the Chinook that really benefits the sonics and reduced noise is replacing the load resistors (vertical board at the rear of the unit) with vishay bulk foils.
Hope that helps
Yes, I did do it. I bought Burr Browns with some really great specs. I wanted to first try them as opposed to some super custom ones due to expense. The BBs were about $15 for two.
I used dual op amps because that is what I think is in there to begin with. I did the 2 in the amp stage, I didn't do the third one in the power section of the amp.
I heard a mild improvement (not a big change) in further noise reduction. There could be other changes that I just didn't take notice of because the surface noise (already quiet with the Chinook) improved a bit. That was easily detectable because I know what noise to expect on certain records from playing them many times before.
This wasn't a huge improvement but worthwhile and cost effective. I'd be curious to try what Johnss recommended--the sparkos labs op amps. But they aren't cheap.
The one thing I can say about the Chinook is that it's going nowhere in my system. I cannot imagine how much I'd have to spend to upgrade. It's a wonderful preamp. I'm really attached to it unlike other pieces of equipment.
Here is a cheaper solution that sparkos labs with strong specs. Some say specs don't matter so much with op amps. I have no idea and will let my ears be the judge.
Exactly soundermn! I also wonder if the Herron would be great yet just different. Since I'm in love with the Chinook it's staying.
The Chinook is the single best piece of gear I've ever bought, including speakers, tube amps, etc. Why? Because it elevated the overall vinyl game into liquid tube honey sound. It's that good.
@johnss , So after a year of using the Burr Brown 2134 opamps in the Chinook, I bit the bullet and bought the Sparkos Labs SS3602.
The Burr Browns provided a subtly nice improvement--mostly a lowered noise floor from what I could tell.
The Sparkos labs are better than the Burr Browns and the stock opamps in the Manley. They sound so smooth and clean. Highly recommended. Not cheap, but worth it.
Where are the RPMs in the circuit of the Chinook?. So far as I know, my steelhead uses discrete transistors plus triodes throughout the audio circuitry. So I am wondering what is going on with op amps in the Chinook. Perhaps they only serve for the relays and switching apparatus when you change settings. In which case I would not expect them to have much effect on sound. Thanks for any insights.
A quote from Mrs. Eveanna Manley on the Chinook TI op amps: “Those opamps are performing as a DC voltage servo in order to bias the FET operational point. Those opamps are not in the signal path. They just stabilize a DC voltage needed to set the operational point of the FETs”.
@lewm - Sounds like you would be correct regarding them having little effect on sound.
Thanks, JT. FWIW, I think Evanna goes by “Ms”, not Mrs. Sometimes we swap out parts just because it gives a feeling of control. But without a schematic and the proper knowledge, it’s a crap shoot. Manley won’t give out schematics even to professional repair businesses;, not that there’s anything wrong with that. It actually makes sense from their point of view.
yep, that is correct. not in signal path but are DC servos for FETs.
lowers the noise floor a ton. The other thing you can do is change out all the loading resistors on the back panel to Vishay VSRS. just like focusing the looking glass much better imaging, quieter backgrounds and micro dynamics much better.
I would attach some photos but can't do it with Agon forums.
I agree that Vishay nude resistors (I don't know about "VSRS"; I do know about nude TX2575, which can be ordered on-line) will be superior to the stock phono load resistors in the Manley phono stages. The TX2575 are superior to just about any resistor ever. However, on the subject of the op amps, was there ever an audible "noise floor" to begin with? I find the Steelhead to be intrinsically very quiet even at full volume. Further, in most cases where there is an op amp used as servo, the device is bypassed by a capacitor or two, just for that reason to render the op amp inaudible. When or if the op amp is intrusive, one cure is to increase the value of the bypass capacitor(s). But I don't hear it, assuming the Steelhead, like the Chinook apparently, uses op amps as servo. Finally, the Steelhead is so full of parts that I am loathe to get in there with my soldering iron, except to change the phono load resistors, and in my case to change the output stage, since that part of the circuit is quite accessible. A lot can be achieved with a little effort on the output stages.