Looking good! I like the idea of firing it all up before you mount it in the chassis. Never thought of that. What are the interconnects that 6L6 approves of? There is so much magical thinking in that area that I'm always on the lookout for something real.
So today I decided to play around with cartridge loading and gain. I am running a Denon DL-103R. I do have enough gain stock, but the inputs are mismatched when switching between CD and vinyl, so I thought I'd try the 65dB setting. I soldered a 470 ohm in parallel to the 1K R14 and I get a terrible distortion. I remove it and it sounds great again. I doubt I'd be overloading it with a 0.25mV cartridge???
Any ideas?
Any ideas?
Don't mess with the gain and just turn Preamp knob more... ? That makes the most sense, simpler is always better.
I installed sockets in mine and routinely change out R14 depending on the cartridge. No issues, although if the gain is too much it overloads my headphone amp.
I agree do not mess with the phono stage gain,
make it up else where,
you are trying to level match a signal source that for one is in the uV to low mV range with something that puts out 2V full scale(CD).
If anything, attenuate the CD input to better match the phono stage. It is called a resistive pad or attenuation, look it up easy to put together or buy one.
make it up else where,
you are trying to level match a signal source that for one is in the uV to low mV range with something that puts out 2V full scale(CD).
If anything, attenuate the CD input to better match the phono stage. It is called a resistive pad or attenuation, look it up easy to put together or buy one.
Since I use a DCB1 buffer going in to an F5 amp, I need all the gain I can get from the phonostage when using a LO cartridge.
You must have a LOT of gain in your pre-amp. I've never been able to run any of my LOMC's into my Pearl Mk1 without a step-up of some kind. I can run a 1:20 SUT with my DL-103R, and not overload anything.
jeff
A Pearl 2 at max gain (65DB) is enough for a LOMC, as long as you have a reasonably powerful system. I don't, so I stick to HOMC or MM cartridges. I'd rather not use a stepup.
I think the presented problem by craigtone needs answering the following question: what is the source of distortion when upping PEARL II gain to the max? Judging by his cartridge output it's not the overload.
The non-linearity of the devices.
The design has a fixed amount of open loop gain, it is not run open open, nor do you want to, so it uses feedback to reduce distortion, stabilize, increase BW etc. The distortion is a factor of the feedback ratio.
A rule of them, it is better to have more gain stages than less, as it easier to control the non-linearities.
In an old japanese stereo, they basically had 4 gain stages
MC head amp(40-60dB), feed to MM phono stage(35-40dB),pre-amp(10dB), power amp (25-35dB). Add it up, there is lots of gain to distribute around.
Problem here is a CD will overload a power amp with 25-35dB gain, it is the odd ball in the equation.
Craigtone!
As I have written before I use Denon DL103R and to get that extra gain I'm using 220k for R15 and that seems to be just the right value. It gives me just about the same volume as a shorted R15 with MM PU.
As I have written before I use Denon DL103R and to get that extra gain I'm using 220k for R15 and that seems to be just the right value. It gives me just about the same volume as a shorted R15 with MM PU.
I have plenty of gain for my DL-103R in the stock configuration (55dB). I run the Pearl 2 into a DCB1 into Aleph J and then some 102dB Cornwalls.
I was just looking to do some volume balancing and saw many others on here use a 300 ohm R14 (also in the PDF per Wayne) to up the gain to 65dB. For some reason I get a lot of distortion. I understand what causes distortion, but why would my Pearl 2 be distorted when others can run at 65dB just fine?
I was just looking to do some volume balancing and saw many others on here use a 300 ohm R14 (also in the PDF per Wayne) to up the gain to 65dB. For some reason I get a lot of distortion. I understand what causes distortion, but why would my Pearl 2 be distorted when others can run at 65dB just fine?
I decided to live with it the way it is. With my Cornwalls, the Aleph J provides enough volume. It is only a handful of vinyl that gives me this issue anyway.
I got the Pearl 2 wired into it's permanent home last night and it looks great and sounds even better! What an incredible phono stage!
Now just waiting on the faceplate back from the machine shop for the Mezmerize (getting an LCD window opening).
I got the Pearl 2 wired into it's permanent home last night and it looks great and sounds even better! What an incredible phono stage!
Now just waiting on the faceplate back from the machine shop for the Mezmerize (getting an LCD window opening).
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Question for the gurus ... I added a mono switch to my build. You can see it to the left of the input jacks in the pic above. When I switch it to mono, I get an out-of-phase hum. Since these boards are mono, should I also be switching the signal negative leads and shorting them as well?