My CH Precision/Magico System

MadFloyd

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Hi Scot,

Thanks for your kind comments and thoughts.

I have been leaving my amps on 24/7 for over a month now. I've owned 4 different Pass Labs amps in the past and they do take a while to get up to speed. The CH are somewhat quicker imo. In fact, with Pass Labs' preamps, you had to keep them on all the time. With CH you can also choose to turn these off as well. Everything sounds good cold... but of course much better after 15 minutes and then an hour.

My amp stands & rack is Steve Blinn Design; inexpensive products that deserves to be upgraded. I have ordered HRS M3X2 platforms for the amps. If they work out I will most likely pursue their SRX racks and M3X2 shelves for all my components. A very expensive endeavor so I'm proceeding slowly.
 

LL21

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My Pass preamps and phono stages were designed to be left on 24/7, or all the time. The big Class A amps, as you suggest, have a standby mode which I used so the amps were never fully off, except when I changed cables/powercords or went on vacation. They sounded their best after a couple of hours being fully on. I kept them fully on during weekends in the winter and standby mode at night after listening. In the summer, it was just too hot, so I always kept them in standby mode when not listening.
Thanks, PeterA. That makes more sense to me. That said, I personally still never left the Gryphons running 24/7. Interestingly, what I found at some point during all the improvements and tweaks is that one day after doing grounding and isolation for several months...the system hit this interesting point at which the performance at switch on was not only remarkably good...the improvement over time as the system warmed up was no longer such a pivotal moment in listening. Not sure why, but I was definitely not complaining!

Lets see what happens with the Robert Kodas.
 
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morricab

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Hi Scot,

Thanks for your kind comments and thoughts.

I have been leaving my amps on 24/7 for over a month now. I've owned 4 different Pass Labs amps in the past and they do take a while to get up to speed. The CH are somewhat quicker imo. In fact, with Pass Labs' preamps, you had to keep them on all the time. With CH you can also choose to turn these off as well. Everything sounds good cold... but of course much better after 15 minutes and then an hour.

My amp stands & rack is Steve Blinn Design; inexpensive products that deserves to be upgraded. I have ordered HRS M3X2 platforms for the amps. If they work out I will most likely pursue their SRX racks and M3X2 shelves for all my components. A very expensive endeavor so I'm proceeding slowly.
I had to sell an amp because of this warmup issue. It was a Single ended hybrid (NAT Symbiosis SE) where the output stage of each channel was a single big MOSFET attached to a HUGE heat Sink. There were two additional, equally large, heat sinks for the output regulation. The crazy thing drew over 800 watts continuously and it weighed over 150lbs so it took a long time to warmup. The first two hours after turning...there was no standby, the sound was good but not amazing...and then the most dramatic improvement of any amp I ever heard occurred. Once warmed up it sounded glorious...shockingly transparent and tonally beautiful...but I could stand listening the first two hours to get to what came after...mostly because I didn’t have that kind of time to listen usually.
 
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Bobvin

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I had to sell an amp because of this warmup issue. It was a Single ended hybrid (NAT Symbiosis SE) where the output stage of each channel was a single big MOSFET attached to a HUGE heat Sink. There were two additional, equally large, heat sinks for the output regulation. The crazy thing drew over 800 watts continuously and it weighed over 150lbs so it took a long time to warmup. The first two hours after turning...there was no standby, the sound was good but not amazing...and then the most dramatic improvement of any amp I ever heard occurred. Once warmed up it sounded glorious...shockingly transparent and tonally beautiful...but I could stand listening the first two hours to get to what came after...mostly because I didn’t have that kind of time to listen usually.
I am so tempted to write something about how the “greenies” would cancel you for burning 8 100w light bulbs for two hours just to start hearing your records… but I don’t want to get cancelled here
 

microstrip

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I had to sell an amp because of this warmup issue. It was a Single ended hybrid (NAT Symbiosis SE) where the output stage of each channel was a single big MOSFET attached to a HUGE heat Sink. There were two additional, equally large, heat sinks for the output regulation. The crazy thing drew over 800 watts continuously and it weighed over 150lbs so it took a long time to warmup. The first two hours after turning...there was no standby, the sound was good but not amazing...and then the most dramatic improvement of any amp I ever heard occurred. Once warmed up it sounded glorious...shockingly transparent and tonally beautiful...but I could stand listening the first two hours to get to what came after...mostly because I didn’t have that kind of time to listen usually.

It is a subject I have never seen properly debated in technical terms - why most tube amplifiers sounds a lot better when hot. What exact parts of the amplifier are sound wise more sensitive in the amplifier? Tubes, resistors, capacitors or even the output transformer?

For simplicity I would prefer to avoid solid state amplifiers in this subject.
 

LL21

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I had to sell an amp because of this warmup issue. It was a Single ended hybrid (NAT Symbiosis SE) where the output stage of each channel was a single big MOSFET attached to a HUGE heat Sink. There were two additional, equally large, heat sinks for the output regulation. The crazy thing drew over 800 watts continuously and it weighed over 150lbs so it took a long time to warmup. The first two hours after turning...there was no standby, the sound was good but not amazing...and then the most dramatic improvement of any amp I ever heard occurred. Once warmed up it sounded glorious...shockingly transparent and tonally beautiful...but I could stand listening the first two hours to get to what came after...mostly because I didn’t have that kind of time to listen usually.
Interesting and very good to know. I have heard very very good things about NAT, and I respect that many will have different opinions about them...but this kind of insight is also good to register.
 

morricab

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It is a subject I have never seen properly debated in technical terms - why most tube amplifiers sounds a lot better when hot. What exact parts of the amplifier are sound wise more sensitive in the amplifier? Tubes, resistors, capacitors or even the output transformer?

For simplicity I would prefer to avoid solid state amplifiers in this subject.
Probably has a lot to do with operating points stabilizing to their correct values. I know my tube amps settle their bias over at least 20-30 minutes
 

microstrip

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Probably has a lot to do with operating points stabilizing to their correct values. I know my tube amps settle their bias over at least 20-30 minutes

We can easily discard such possibility - the operating points change a lot more with tube type and parameters and mains variations. And the sound does not change accordingly.

If it was the case, the designers could easily stabilize the operating points, as it happens in some designs. BTW, when we measure tubes the parameters became stable after three minutes.
 

morricab

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We can easily discard such possibility - the operating points change a lot more with tube type and parameters and mains variations. And the sound does not change accordingly.

If it was the case, the designers could easily stabilize the operating points, as it happens in some designs. BTW, when we measure tubes the parameters became stable after three minutes.
No, this depends on the design of the amp and the nature of the bias scheme. I have seen you n manual bias amps the values drifting significantly over at least 30 minutes (in amps where you can easily check it). Adjusting that bias purposely once it has stabilized has a very clear impact on the sound character, so why wouldn’t it when it is drifting around before it stabilizes?
 

microstrip

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No, this depends on the design of the amp and the nature of the bias scheme. I have seen you n manual bias amps the values drifting significantly over at least 30 minutes (in amps where you can easily check it). Adjusting that bias purposely once it has stabilized has a very clear impact on the sound character, so why wouldn’t it when it is drifting around before it stabilizes?

You refer to exceptions, I try to address the general case. It is extremely easy to check the relative output bias in power amplifiers - just connect a 10 euro power meter in series and watch the reading. Or get an Audio Research tube amplifier with meters. ;) Bias becomes stable after a few minutes. Adjusting bias can improve the sound quality, but does not make the nigh and day magic difference between a cold and fully warmed up amplifier.

Can you put a number in the significant variation you refer? 5, 10 , 20, 50%?

Another argument is that you can overbias an amplifier in a way it has close to nominal bias during the first 15 minutes and it will still sound like a cold amplifier at the warmup period. I tried it!

Remember that most simple tube amplifiers have variations of bias around 10% just because of the typical allowed mains variations.

In push pull amplifiers bias can be much more critical, as many push pull transformers are calculated to have zero average DC current in the primary and bias imbalance between sections can cause distortion.
 

andromedaaudio

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As far as the feedback setting, I do prefer it with 0% (probably the more 'tube-like' value) but I also like it with 10 or 20 depending on my mood & music. I have the gain set at +1 which adds a little more drive to my ears.
Hello ian .

Nice system as i have already said before and nice guitars .
But as i read here you run your CH power amp with 0 % feed back and you have no complaints in the bass region , the bass is tight / deep /articulate ??.

Your speaker is stated by Magico at 91 db .
They sometimes are a bit optimistc , may be yours are 89- 90 db for example .
Looking at several Magico designs ( i couldnt find a third party measurement for the M pros ) their impedance doesnt drop below 2 below ohms for their speakers ..
They are mostly in the 2-3 ohm range even for the Q 5 .
If you have no problems in the bass region ( with 0 % feedback ) then i dont understand marty s bass problem wit his 92 db / 2 Ohm minimum ( stated by wilson )
 

bonzo75

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Like Gian said, it could be a Soulution pre - CH power mismatch. The other thing is that Marty has an extremely big and acoustically designed room, 35 * 25 * 14, and his room did produce stellar bass when he was using the DRC from his Piperdreams to his JL Gothams. So he has crazy expectations of bass nor reproducable in normal not built for bass rooms.
 

andromedaaudio

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I d like to have Ian s opinion on this as well as he lives with/ owns the gear ;)

As i read more about CH pre / power amps they seem to have a lot of adjustability s ( local - global feedback ) , so may be marty s need either the CH pre / extra adjustments done .
In either case i think his dealer should contact CH for more info / provide a CH pre to try and if one is not satisfied afterall he can contact CH directly to have their opinion, as they will know exactly what their amps can do or not do on certain loads.


Ps by the way Al great write ups
 
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PeterA

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Ian, I’m just revisiting your thread and really appreciate the new system thread with your updated components. The photos are great and I appreciate Tim’s observation about how different the various systems are of the five WBF Boston members: Madfloyd, Al M., Ack, VLS, and I.

Our visits do indeed lead to learning and some spirited discussions. I look forward to reading about and hearing your future changes.
 
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PeterA

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I had the great pleasure of spending most of a day with Ian yesterday, listening to his system and helping him set up a new piece of gear. I will let him break that news. After our work was done, we listened to the same music again, and we both heard a significant difference, and I think a nice improvement.

Ian's system is really sounding good these days with a much fuller and evenly balanced midrange to lower frequency range. There was wonderful weight and rich tone to stand up bass, lower horns, and large scale choral music. The music had a real foundation which made it sound more natural that the last few times I had visited. As Ian often does, he introduced me to some new music. This time it was to a delightful piece by Stravinsky. See photo below. The woodwinds and horns sounded simply beautiful and I marveled at their individual sounds and the overall gestalt. Given the reason for the visit, we did a bunch of critical listening, but this music was so good, I tended to get lost in the performance and had to keep reminding myself to listen for differences.

I have not heard such rich, deep tone and bass quality with such body and weight in his system before. It really was a joy. We later compared two IC cables which presented two starkly different takes on the same music. Timbre, color, body, weight were about the same, but the presentation was very different. The first presented the instruments in the Stravinsky piece as very separate, distinct, sounds, each with a kind of black space/halo around it. Imaging of each instrument was pinpoint in relation to the rest on the stage, and outlines were precise. The sounds came from specific locations in the room and remained distinct. The second cable presented the sounds of the various instruments from fairly clear positions on stage. There was laying and localization, but the sounds filled the space and overlapped with the other sounds. Eventually they blended and reflected around the hall in which they were recorded. The sound flowed outward and expanded toward the listener to a much greater degree. The imaging was not as precise, and there was no black background or space around the individual instruments. One presentation was full of life and energy. It was organic. The other seemed impressive but somewhat flat, almost like a painting.

I can see how each presentation can be preferred for what they were, but the difference in these two presentations was remarkable to me. Unfortunately, I did not hear these two cables before we made the gear/set up change, so I do not know if it would have been as pronounced a difference. Time will tell which presentation Ian will prefer.

It is always fun to visit Ian. He is a great host, always in a good mood, and he always has some interesting music to share. Sometimes, as was the case yesterday, we made some changes and did a comparison. I never really know what to expect when I invite myself over for an afternoon, but I always look forward to the visit. This time I learned some interesting stuff, and found another LP to order. Many thanks, Ian. I had a wonderful afternoon as usual.



IMG_2395.jpg
 

Ron Resnick

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Thank you, Peter, for that wonderful report!

Which interconnect cable presentation did you prefer?
 

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