Input Capacitance and SUT's
I agree with 6L6. Start small and work up. Most good phono cables have on the order of 20-30 pf per foot. Most MM cartridges need a TOTAL of 250 to 400 pf to control the resonant peak of the fixed coil inductance...100 pf comes from the preamp, 60-90 pf from the cable, so theoretically you may only need 50-200 pf for the load cap.
SUT's - it all depends on the MC cartridge. Low impedance cartridges need low impedance inputs, hard to get with an SUT. Cartridges with air core coils (Fidelity Research, Denon DL-S1) are very low output and are compromised by ANY SUT due to interactions with the transformer inductance.
In my opinion a phono preamp with high enough gain to handle any cartridge, and high input impedance provides the flexibility to load the cartridge non-inductively to best match it's characteristics. That is the definition of the Pass / Colburn approach and provides the best way to match a wide variety of MC's. Using an SUT can provide good sound, but the SUT must be matched to the particular cartridge you want to use for best results.
I agree with 6L6. Start small and work up. Most good phono cables have on the order of 20-30 pf per foot. Most MM cartridges need a TOTAL of 250 to 400 pf to control the resonant peak of the fixed coil inductance...100 pf comes from the preamp, 60-90 pf from the cable, so theoretically you may only need 50-200 pf for the load cap.
SUT's - it all depends on the MC cartridge. Low impedance cartridges need low impedance inputs, hard to get with an SUT. Cartridges with air core coils (Fidelity Research, Denon DL-S1) are very low output and are compromised by ANY SUT due to interactions with the transformer inductance.
In my opinion a phono preamp with high enough gain to handle any cartridge, and high input impedance provides the flexibility to load the cartridge non-inductively to best match it's characteristics. That is the definition of the Pass / Colburn approach and provides the best way to match a wide variety of MC's. Using an SUT can provide good sound, but the SUT must be matched to the particular cartridge you want to use for best results.
There audio files from that cart amongst several other MC/MM/MI models to download and listen to. From that nice gent: Hi-Fi Cartridge Reviews - Moving Coil Cartridges
soldersmoker - This phonostage is truly incredible. I am sure you will be pleased with it.
If you have any (general or specific) questions along the way please feel free to contact me or ask them in the forum. There are a whole bunch of people here who would love to see you have a successful build.
If you have any (general or specific) questions along the way please feel free to contact me or ask them in the forum. There are a whole bunch of people here who would love to see you have a successful build.
Mine is making its stereo debut on the main amp and speakers for the first time tonight. It is sounding very good. Not a world of difference with the phono stage of my Sony ES amp, but subtle improvements is my first impression. But I will have to compare them more to make any definitive statements. Now that it is star grounded to the chassis, all hum is gone. Noise/hiss is about the same as the Sony, which is very good. I would't call it dead silent (the cd input is what I'd call dead silent) but considering all the extra gain it is very silent.
What is now left to do? I have some 0.5mm pure silver wire and pfte insulation on the way and plan to use that for internal wiring. Don't know if it will make an audible difference, but it just seems right to use noble materials for a great amp like this Then I will try to set P1 one more time, fix the prints in the case with their self ahesive feet, close the case, enjoy music and post some pictures over here...
What is now left to do? I have some 0.5mm pure silver wire and pfte insulation on the way and plan to use that for internal wiring. Don't know if it will make an audible difference, but it just seems right to use noble materials for a great amp like this
Then I will try to set P1 one more time, fix the prints in the case with their self ahesive feet, close the case, enjoy music and post some pictures over here...Pearl1.5 full schematic:
It's just cobbled together from the Pearl2 pdf (I hope Nelson and Wayne don't mind!
)And that's pretty much what the circuit is too! A Pearl2 with only the positive power supply, the first stage and riaa ... and then a Pearl1 2nd stage with 2x 170 instead of one 389.
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Hmm tough call to say in general because he uses one TT, arm, amp, recorder for all. So some carts may very well perform better or worse with other TT and gear. There is the standardization element in his comparison though that is valid for that system context. For balance between performance and value I liked the DL-304 for LOMC, the 10X5 for HMC, the 881S for MM. For vintage tone super value the cake goes to 103R again. Best pricey MM the 2M.
The biggest factors in cartridge selection are loading, gain, and compliance.
Gain - The Pearl 2 has enough for practically anything. No worries there.
Loading - This is DIY, we can load it any way we want, and the Pearl 2 also has places on the PCB for R and C loading. Nice.
Compliance - This is a bit weirder, but there are a few things to know about - In general, only 'old fashioned' or 'classic' cartridges have compliances that don't jive with modern arms. (And by modern, I mean about 1970 forward) The other cool thing is all you need to do to a modern arm to use it with the classic carts is add mass. Easy.
As for preference, I have only HOMC and MM, and of those carts, I prefer HOMC. I believe that's more because the ones I have are simply better carts than my MMs.
So, to conclude, there is practically no limit to the type of cartridge you can use with this phonostage. Except your budget...These things can get silly expensive!
Gain - The Pearl 2 has enough for practically anything. No worries there.
Loading - This is DIY, we can load it any way we want, and the Pearl 2 also has places on the PCB for R and C loading. Nice.
Compliance - This is a bit weirder, but there are a few things to know about - In general, only 'old fashioned' or 'classic' cartridges have compliances that don't jive with modern arms. (And by modern, I mean about 1970 forward) The other cool thing is all you need to do to a modern arm to use it with the classic carts is add mass. Easy.
As for preference, I have only HOMC and MM, and of those carts, I prefer HOMC. I believe that's more because the ones I have are simply better carts than my MMs.
So, to conclude, there is practically no limit to the type of cartridge you can use with this phonostage. Except your budget...These things can get silly expensive!
Listening to the files via AKG K 271, I quite enjoyed AT OC 9 looking at the price vs performance. I have to pass them through my system, though.
Regarding gain and loading the Pearl II can be adapted to most cartridges like 6L6 says. Matching a cartridge with the tone arm is important. See this article on the Ortofon website: Cartridge & tonearm resonance frequency
In general high compliance MM carts don't match well with heavy tone arms and low compliance MC's don't match well with low mass tone arms. Although some have a combo that should not match but still seems to be working fine.
In general high compliance MM carts don't match well with heavy tone arms and low compliance MC's don't match well with low mass tone arms. Although some have a combo that should not match but still seems to be working fine.
I just got into vinyl a few months ago and the learning curve is steep! Holy crud, there's a lot to know!
Here's the formula
The resonant frequency:
Fr= 1000 / [2 pi * sqrt(M * C)]
where, pi = 3.14 (approx), M = total effective mass in gm of the arm plus cartridge, and C = compliance of the cartridge in um/mN (um is micrometer and mN is milliNewton; um/MN is the same unit as micro cm/Dyne).
You're looking for Fr=~10Hz to keep the resonance away from any music (20Hz) or turntable 'rumbles' (<5Hz?)
Make sure you're using the 'dynamic compliance' not the 'static compliance'!
Arm + cart = total effective mass
For my SL-220, the arm is 230mm and 13g.
(Apparently this arm has the same geometry and other features of the SL-1200!)
http://www.diyaudio.com/forums/anal...ntry-table-technics-sl-220-upgrade-paths.html
My Ortofon OM5E is 5g
http://www.ortofon.com/products/cartridges/cartridges-omomp-series/om-5e
13g + 5g = 18g =M
Compliance, dynamic, lateral = 20 µm/mN =C
Fr= 1000 / [2 pi * sqrt(M * C)]
Fr= 1000 / [2 pi * sqrt(18 * 20]
Fr= 8.4Hz
Here's a spreadsheet with a few carts in it (Red Ed, M97eX, AT440MLa, 2M Red, Grado [green, black, red, blue], and the OM5E+stylus10 that I have) that I was checking with my
Here's the excel (2003) file:
View attachment Turntable compliance calculator.zip
Cheers,
Jeff
PS As well, from the manual's recommendation of 5.5 to 8.5 I used the spreadsheet to reverse calculate the compliance spread for these cart weights
5.5g to 8.5g as recommended in the manual:
5.5g, dyn comp~14
8.5g, dyn comp~12
(assuming linear type relationship: 7g, dyn comp~13?)
for Fr~10z
So, according to this I'm looking for carts with:
Light
5.5g, comp~14
...
7g, comp~13
...
8.5g, comp~12
Heavy
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Thanks Wellerman, it doesn't get 'clearer' than Ortofon
Cartridge & tonearm resonance frequency
Cartridge/tonearm systems resonance frequency
To maintain a cartridge/tonearm system resonance frequency within the acceptable range of 7 to 12 Hz, whereas 10 Hz recommended, it is necessary to choose a cartridge with the mass and compliance matching the tonearm
When selecting either MC or MM cartridges for your record player, total mass of tonearm (including cartridge and headshell) has to be taken into account in relation to the mechanical compliance (elasticity) of the cartridge cantilever system.
The high mass of the combination needs low mechanical compliance, otherwise record warps can easily provoke tonearm vibrations at frequencies around 4 to 6 Hz, that will bring degradation of performance (at least 8 Hz is advisable)
A phono cartridge with the compliance in the range of 5 to 10 µm/mN is considered as a very low compliance cartridge, a cartridge with the compliance in the range of 10 to 20 µm/mN is moderate compliance cartridge and a cartridge with the compliance value above 35µm/mN is very high compliance cartridge.
Low mass arms* mate well with both moderately high and very high compliance phono cartridges
*A tonearm whose effective mass is rated at 10 grams or below is considered low mass (e.g. early SME’s, Grace 747).
Moderate mass tonearms** are good companions for moderate to low compliance cartridges
**A tonearm whose effective mass is rated between 11 and 25 grams is considered moderate mass (e.g. SME 309, IV, IV-Vi, V, Triplanar, Graham). Arms above 25 grams of mass are high mass in nature (Eminent Technology, Dynavector).
If a low compliance cartridge is used with a low mass tonearm, undesirable resonances can occur in the audible range. Mistracking may also be a problem.
When a high compliance cartridge is mated with a moderate mass tonearm, resonances in the infrasonic range may occur in addition to some unwanted high frequency damping.
PS And they use "whereas", haven't heard that outside of a debate introduction in a while!
Cartridge & tonearm resonance frequency
Cartridge/tonearm systems resonance frequency
To maintain a cartridge/tonearm system resonance frequency within the acceptable range of 7 to 12 Hz, whereas 10 Hz recommended, it is necessary to choose a cartridge with the mass and compliance matching the tonearm
When selecting either MC or MM cartridges for your record player, total mass of tonearm (including cartridge and headshell) has to be taken into account in relation to the mechanical compliance (elasticity) of the cartridge cantilever system.
The high mass of the combination needs low mechanical compliance, otherwise record warps can easily provoke tonearm vibrations at frequencies around 4 to 6 Hz, that will bring degradation of performance (at least 8 Hz is advisable)
A phono cartridge with the compliance in the range of 5 to 10 µm/mN is considered as a very low compliance cartridge, a cartridge with the compliance in the range of 10 to 20 µm/mN is moderate compliance cartridge and a cartridge with the compliance value above 35µm/mN is very high compliance cartridge.
Low mass arms* mate well with both moderately high and very high compliance phono cartridges
*A tonearm whose effective mass is rated at 10 grams or below is considered low mass (e.g. early SME’s, Grace 747).
Moderate mass tonearms** are good companions for moderate to low compliance cartridges
**A tonearm whose effective mass is rated between 11 and 25 grams is considered moderate mass (e.g. SME 309, IV, IV-Vi, V, Triplanar, Graham). Arms above 25 grams of mass are high mass in nature (Eminent Technology, Dynavector).
If a low compliance cartridge is used with a low mass tonearm, undesirable resonances can occur in the audible range. Mistracking may also be a problem.
When a high compliance cartridge is mated with a moderate mass tonearm, resonances in the infrasonic range may occur in addition to some unwanted high frequency damping.
PS And they use "whereas", haven't heard that outside of a debate introduction in a while!
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Now that I've almost finished testing the Pearl II, I wonder if I can improve the power supply some more. I now have the power supply featured in the Pearl II article (+ 2 CL60's), and as can be seen in post 1711 there is not a lot of room left in the PSU chassis. Things I was thinking about:
1. bypassing the electrolytics with a film cap. Useful? Which value would be good?
2. replacing the rectifier bridges with discrete diodes. Ideally with LQA06T300 from Power Integrations, but they are hard to come by. Would eliminate the need for a snubber. Any other suggestions for diodes?
3. Snubbers across the secondary. I read the Hagerman article, and I will not be able to measure what is needed to calculate custom RC values for my transformer. Any suggestions for values that would be OK with a 50VA 2x24V toroid?
Any comments welcome. Soon I will finish the Pearl II and post some pictures of the final result (and impressions of the sound).
1. bypassing the electrolytics with a film cap. Useful? Which value would be good?
2. replacing the rectifier bridges with discrete diodes. Ideally with LQA06T300 from Power Integrations, but they are hard to come by. Would eliminate the need for a snubber. Any other suggestions for diodes?
3. Snubbers across the secondary. I read the Hagerman article, and I will not be able to measure what is needed to calculate custom RC values for my transformer. Any suggestions for values that would be OK with a 50VA 2x24V toroid?
Any comments welcome. Soon I will finish the Pearl II and post some pictures of the final result (and impressions of the sound).
I've played files on my system and I ended up with a lesson one of those evenings. Differences where extremely subtle to my unexperienced ears or to my current system for that matter. I can hear pleasant virtues of DL-304 vs budget Denons. But I would have hard time justifying it's difference in price to my brain and wallet. As for DL-S1 it's impossible for me to grab hundreds $ difference. Maybe if files were played through a DAC, maybe if this cart would played on a better phono it would tell a different story to me.
I found 10X5 pleasantly dynamic in comparison, pity there was only one file for that cartridge. I also quite liked AT-OC9ML/II. Sounded like a well-traveled japanese gentleman. Dig the groove and the tone of DL103R too. I'm going to do some blind testing, just randomly playing files and picking what I like the most some time.