The CMOQ-3 has been recommended to me by Mark Schneider at Cable Solutions as being compatible. The Cinemag website doesn't have a detailed spec sheet on them, but the pinout drawing looks like it would be easier to work with to make an adapter board from readily available single sided PCB stock. Question is whether the High Nickel would be preferable to the Low Nickel option...
^ Maybe ask Mark.
You could look at the spec sheets for the CMOQ-4 and compare the two... if one can assume that the high nickel vs standard in the 3 behaves roughly the same as the 4.
Another alternative may be to call CineMag. Dave is a heckuva guy.
Otherwise... you're probably just going to get a lot of 🤷♂️
Or you could just go with the general idea that the high nickel is better...
You could look at the spec sheets for the CMOQ-4 and compare the two... if one can assume that the high nickel vs standard in the 3 behaves roughly the same as the 4.
Another alternative may be to call CineMag. Dave is a heckuva guy.
Otherwise... you're probably just going to get a lot of 🤷♂️
Or you could just go with the general idea that the high nickel is better...
The CineMag CMOQ-4LPC is closer to the Jensen JT-123-PLPCH in that both use 50% nickel alloy. Nelson mentioned the -4LPC specifically, and that happens to also be what I have on hand. If the CMOQ-3 transformers look especially tempting, it is certainly possible to make one's own adapter. I have done similar projects using single sided copper plated boards, drawing the traces with a heavy Sharpie pen and etching with Ferric Chloride. I recommend doing that out in one's garage or other well-ventilated space. The etching solution takes a long time to work.
Based on my samples, the CineMag compatible footprint in the newer F6 Diamond PCBs needed slightly larger mounting holes. (Manufacturing tolerances) Those hole sizes have already been corrected. I wanted to run the boards in my F6 before releasing the Gerbers, just to make sure everything is good.
Based on my samples, the CineMag compatible footprint in the newer F6 Diamond PCBs needed slightly larger mounting holes. (Manufacturing tolerances) Those hole sizes have already been corrected. I wanted to run the boards in my F6 before releasing the Gerbers, just to make sure everything is good.
Thank you for the advice. I don't see electrical characteristics datasheets for the CMOQ-3 on their website, and the CMOQ-4 can be easily mounted to a daughter board. I have a CNC mill in the garage, small cutters can be used for "trace isolation" and small drill bits used to get the right hole sizes. I'm leaning in the direction of the CMOQ-4L since it seems to be the proven alternative, and a mounting adapter can be easily fabricated.
I think it is not so simple as that. Higher permeability fit to nickel usually results in less distortion so long as saturation of the core is not approached. If absolute fidelity is desired AND the maximum signal level is within the most linear operating area of the transformer, then higher nickel is favored.
On the other hand, if either signal levels are high and likely to closely approach the saturation level or the transformer, OR the distortion associated with saturation is desired, then lower nickel is favored.
Some may wonder why saturation of transformer may be desirable. In recording applications, especially, the signal compression and generation of harmonics lead to a “thickening” of the sound which some engineers and listeners desire. This saturation compression/distortion can be heard in many recordings and can be part of the specific”sound” that listeners associate with, for example, rockabilly, early garage rock, and even 1970s and 80s classic rock recordings. Others ways of thickening the sound include overdriving the Mike preamps, and overdriving the tape beyond its maximum operating level. Sadly, I am not experienced enough to distinguish between these types of achieving signal thickening.
Bottom line: each builder ideally should listen to the different transformers ion order to determine what sounds best to their taste. Absent that, having a good idea of what sound you are trying to achieve and evaluating other builders’ descriptions of the sound of different transformers may be the only practical approach.
On the other hand, if either signal levels are high and likely to closely approach the saturation level or the transformer, OR the distortion associated with saturation is desired, then lower nickel is favored.
Some may wonder why saturation of transformer may be desirable. In recording applications, especially, the signal compression and generation of harmonics lead to a “thickening” of the sound which some engineers and listeners desire. This saturation compression/distortion can be heard in many recordings and can be part of the specific”sound” that listeners associate with, for example, rockabilly, early garage rock, and even 1970s and 80s classic rock recordings. Others ways of thickening the sound include overdriving the Mike preamps, and overdriving the tape beyond its maximum operating level. Sadly, I am not experienced enough to distinguish between these types of achieving signal thickening.
Bottom line: each builder ideally should listen to the different transformers ion order to determine what sounds best to their taste. Absent that, having a good idea of what sound you are trying to achieve and evaluating other builders’ descriptions of the sound of different transformers may be the only practical approach.
I believe this was his 4th and latest version. I’m planning on ordering some.
Indeed. I have found that my system is quite different from many others here that the only way is to build and listen for myself. That’s more fun than to live vicariously through a builder’s descriptions to be honest. Compared to many tube designs, these transformers are inexpensive and easily sold if desoldered with care (Hakko FR-300 to the rescue!).
Best,
Anand.
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That would explain the soft clipping I saw on the O'scope when I was testing the original F6. Even driven into very hard clipping, my 300Mhz scope showed a rounded edge on the waveform. It probably will save tweeters if you overdrive the amp.
I just got the Diamond boards,and am waiting for my Mouser order. I put a "Project List" together at Mouser and will try to post details once I verify its suitability. It might save some builders some time searching for components.
I just got the Diamond boards,and am waiting for my Mouser order. I put a "Project List" together at Mouser and will try to post details once I verify its suitability. It might save some builders some time searching for components.
It may be jumping the gun, but this is my BOM for the F6 Diamond. I was going to use the extra green LEDs I have for the indicators. Feel free to upgrade this file.
I also just ordered a quantity of the Zen Mod Cinemag CMOQ-4L to Jensen PC boards from JLCPCB.com. They will probably arrive in a week. I ordered 30 since most of the cost was shipping.
I also just ordered a quantity of the Zen Mod Cinemag CMOQ-4L to Jensen PC boards from JLCPCB.com. They will probably arrive in a week. I ordered 30 since most of the cost was shipping.
This is going to be very helpful. I will take a closer look when I have some more time.
I noticed some RN60 size resistors which might be tricky to fit on the PCBs, depending on their location.
I would like to add some alternate parts that have been under discussion recently. In place of the IRFP240, I recommend IXTQ75N10P. In association with this I substitute a LTL1CHTBK5 blue LED for one of the greens in each string. This helps set the higher Vgs needed by the 75N10P transistors.
I noticed some RN60 size resistors which might be tricky to fit on the PCBs, depending on their location.
I would like to add some alternate parts that have been under discussion recently. In place of the IRFP240, I recommend IXTQ75N10P. In association with this I substitute a LTL1CHTBK5 blue LED for one of the greens in each string. This helps set the higher Vgs needed by the 75N10P transistors.
Yes, one would have to tightly bend the RN60 resistor leads at the end of the body to fit the pcb, and even then the leads would be wider than the resistor pcb holes - this should be avoided as it is not good practice and against many standards - especially military.
The Dale CMF55 types are a better option, along with others from Yageo, Beyschlag etc....
The Dale CMF55 types are a better option, along with others from Yageo, Beyschlag etc....
All else is Ok with the list (just replace the RN60).
The Panasonic FC series electrolytic capacitors are very good and will be around for a while.
I have been using the Nichicon UKZ1E102MHM "MUSE" in my F6 builds. They are listed as End of Life but there are still some available. I do not feel a need to add film caps in parallel with these. Just my personal preference.
The Panasonic FC series electrolytic capacitors are very good and will be around for a while.
I have been using the Nichicon UKZ1E102MHM "MUSE" in my F6 builds. They are listed as End of Life but there are still some available. I do not feel a need to add film caps in parallel with these. Just my personal preference.
I'm putting my Mouser parts order together. I noticed that the original BOM had #588-WNC100FET resistors for R17,R18. These resistors are HUGE! Should I get 71-CMF55100R00FKEB for this use? I'm thinking the 1/2 watt should work? I'm also planning to use the #71-CMF5510R000FHEK resistors for R24, R25. Should fit the board nicely. My thought on the caps is temperature and life since they are part of the bias supply and shouldn't affect the signal (sound). Since I'm going to order from Mouser again, I'm going to get the IXTQ transistors and LTL leds. Should be a fun build. When I'm done I'll try to update the BOM I posted earlier.
