I haven't used my turntable for probably 2-3 years. Today I changed the cartridge to the Benz Ace L and am listening to my former favorite records... it's so beautiful. I have to build the Pearl 3, soon, quickly... actually the day before yesterday.
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These results are indicative of something being quite wrong…
There should be no noise at normal playback levels, I’ve used 1656 in a build and it’s quiet as a tomb, and there should be no changes in noise, oscillation, pulsing, and particularly gain when you change opamps.
As you suggest, it is quite plausible that you are running in to issues with LC resonance with HOMC, so yes, stuff the input zobel asap.
My second build for a friend:
Any HANA SL users here? Please share your experience with Pearl 3 🍻
Any HANA SL users here? Please share your experience with Pearl 3 🍻
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Thanks Jim. Compared to DL103 or 103R and other low/medium budget MCs what are the main pros/cons?
You’ve been on this forum long enough to know that I don’t do comparisons…
…and anyway, I’ve never heard a DL103 or variant.
I do like the Hana SL very much.
…and anyway, I’ve never heard a DL103 or variant.
I do like the Hana SL very much.
I got a chance to do this sooner than I thought. 2.2K in parallel with the 750R at R1 gives a collector voltage of 7.7 V, a base voltage of 6.9 V and an emitter voltage of 6.3 V. Voltage drop over the now 559R combined R1 is 6.65 V (14.35 - 7.7V). I'll do the other channel and see how it sounds.
Sounds great! Does it sound better? The difference seems to be in high frequency transients such as percussion instruments. I think the saturated Q5 was acting as a subtle form of compression, such as one sees in guitar amp "sag." It still sounded pretty darn good...I attributed that to vinyl recordings, which I haven't listened to in years.
Thank you, everyone for your help, particularly hifiZen, MEPER, GTKAudio, DualTriode, 6L6, Wayne, and anyone else I may have missed.
Thank you, everyone for your help, particularly hifiZen, MEPER, GTKAudio, DualTriode, 6L6, Wayne, and anyone else I may have missed.
Hello,
Maximizing R1 maximizes the voltage drop across R1 as a result minimizes the voltage usable by Q5 and the Jfets.
If the voltage available to the Jfets is reduced they also may begin operating on the shoulder their curve. If you like curves see the attachment attached below.
The Pearl 3 already has in the range of 10dB more gain than most other Phono Preamps.
Thanks DT
I've been stuck on Grado's moving irons for like 20 years. A weird combo of inductance insensitive, low output and 47K resistance load.
As I moved up the line, I keep admiring them more and more... but then...
...Unfortunately, when it comes to cartridges and turntables, DIY doesn't exist. So it's hard to have a lot of experience and cartridges tend to be such a subjective thing. You do pay money. Lots of money. In no time at all, those cartridges cost more than a DIY amp... and there's no way I'm buying a used cartridge. Used TT's are OK, used cartridges, not in my life force.
So, pretty much once your turntable set up has achieved short term nirvana it's hard to create a parallel path.
Is it better to reach Non Plus Utra Nirvana with a single turntable and cartridge or split your money and achieve Goodum Enougphum Nirvanus with two turntables and two cartridges? Maybe it's the power supply? Oh.... maybe it's the Signature Molybdenum Doped cable vs the DC biased Quad Balanced harness?
Then you open up the floods of audiophilia nervosa with a healthy dollop of neurosis (*).. does Cartridge A sound better than Cartridge B because the DD/bent tonearm or the BD/straight tonearm? Should it be a 9", 10" or 12" transcription tonearm? And who in their mind has two identical turntables to run different cartridges?
Anyhow, I've never heard the Hana SL, although the reviews are very good. Heard identical about the DL103.
But then, they are not comparing them with a Grado Master 2 low output with a P3...
Oh, my wife and I discussed my hobby today. It was a dangerous path to be in.
BTW: Purgatory note... my new car has a Bose audio system. Will that wreck my highly trained audiophile Golden Ears?
(*) Ever owned toobes? Then you understand....
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What an amazing photograph; you could probably sell it to Benz.
In particular - not a speck of dust visible anywhere ! How do you accomplish this ? Some sort of ionizing device ?
6L6' pic was not far behind.
The Cascode JFET front end is inside a feedback loop with U1a, and contributes only to the open loop gain. The closed loop gain is set by R9 & R8, and is not affected by R1. Thus the preamp gain does not change with R1. Instead, increasing the JFET front end gain increases the amount of negative feedback, which will reduce the noise contribution coming from the rest of the input stage after the cascode front end (R10, U1a).
As long as R1 does not drop so much voltage that Q5 starts to saturate, Q5 emitter voltage will stay the same, and the JFETs operation will be unaffected by R1. So the optimization is to make R1 as large as possible while leaving enough Vce available for Q5 to operate well.
Going beyond this, as you note, could be detrimental.
I plan also to do this "exercise". The largest resistor I have that is less than R1 (750R) is 475R. As I have a little more voltage drop over R1 (9V) than mworthin then a little less than mworthin 559R (resulting value) may work well. I can replace it from top.
I made some measurements "as is" so I can compare voltages after change of R1.
Left: Vr1 = 9.4V, Vce_q5 = 23mV
Right: Vr1 = 9.3V, Vce_q5 = 25mV
I also did some optimization of R1. Seems I can get away with 470R; Vc = 6.92, Vb = 6.59, Ve = 5.99. Safe point on the curves Dualtriode and Mark Johnson posted. With 500R Vb drops below Vc, and from somewhere way back in the Pearl 2 thread I remember that this was not good.
I'm not blaming the opamps. These were parts approved by Wayne, and he wouldn't have approved them if they were as noisy as I experienced. So something is wrong, which seems to affect some opamps more than others. I guess I should build it into an enclosure (request sent to Modushop) with proper grounding as that might help too.
I do have a scope and it does say FFT on the box, is that what I need to make a noise spectrum? I can also run through the time base to see if there is noise at specific frequencies.