To follow-up with the discussions that were had on the latchups of bipolar op amps -
Strange behavior of a simple LME49710 instrument (guitar) buffer circuit - Audio Amplifiers Forum - Audio Amplifiers - TI E2E Community
Pro Audio Design Forum • View topic - LM4562, LME49710, LME49720 Start-up Behavior
One of the things mentioned in the comments was - "note that the app notes for the
LM4562, LME49710, etc. all showed circuits with low resistance values". The THS4031
data sheet show circuits with 330 ohms feedback, in most cases, as it's designed to drive 75 ohm video cables.
Strange behavior of a simple LME49710 instrument (guitar) buffer circuit - Audio Amplifiers Forum - Audio Amplifiers - TI E2E Community
Pro Audio Design Forum • View topic - LM4562, LME49710, LME49720 Start-up Behavior
One of the things mentioned in the comments was - "note that the app notes for the
LM4562, LME49710, etc. all showed circuits with low resistance values". The THS4031
data sheet show circuits with 330 ohms feedback, in most cases, as it's designed to drive 75 ohm video cables.
Well, after reworking everything on regulator part it seems working now with the 5v reference. I'm unable to say what was wrong and i hope it will remain like this 
Also bass has improved to a pleasant level after installing KSC1845 and changing the the two resistor values in RIAA network (720k to 700k and 2k7 to 820R).
Unfortunately my cart Denon Dl110 has a slight imbalance between channels (well known problem) and i need your advice wich resistor to adjust in order to estabilish a balance between channels.
My Fluke DMM measure on a 1khz test track 0.55v on left and 0.46V in right channel. (Ac RMS)
Also bass has improved to a pleasant level after installing KSC1845 and changing the the two resistor values in RIAA network (720k to 700k and 2k7 to 820R).
Unfortunately my cart Denon Dl110 has a slight imbalance between channels (well known problem) and i need your advice wich resistor to adjust in order to estabilish a balance between channels.
My Fluke DMM measure on a 1khz test track 0.55v on left and 0.46V in right channel. (Ac RMS)
I don't have the circuit here, but the two resistors that set the closed loop gain can adapted to give one channel a bit more gain than the other. It's only 20% or so.
Edit: found a stray copy - it's less simple as I thought, because the feedback 'resistor' is actually the RIAA network. You don't want to fiddle with that. What you can try is to increase R3 a bit on one channel and decrease a bit on the other. Maybe 10% or so, maybe even less.
Jan
Edit: found a stray copy - it's less simple as I thought, because the feedback 'resistor' is actually the RIAA network. You don't want to fiddle with that. What you can try is to increase R3 a bit on one channel and decrease a bit on the other. Maybe 10% or so, maybe even less.
Jan
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Well, after reworking everything on regulator part it seems working now with the 5v reference. I'm unable to say what was wrong and i hope it will remain like this
Also bass has improved to a pleasant level after installing KSC1845 and changing the the two resistor values in RIAA network (720k to 700k and 2k7 to 820R).
Unfortunately my cart Denon Dl110 has a slight imbalance between channels (well known problem) and i need your advice wich resistor to adjust in order to estabilish a balance between channels.
My Fluke DMM measure on a 1khz test track 0.55v on left and 0.46V in right channel. (Ac RMS)
You could measure the coil resistance by adding a 1K resistor in series with the coils. This may determine if it the coils are balance or not.
Looking on the cartridge spec the coil resistance is 160R
Would a small resistor about 10R-30R in series with the left channel work.
As your coil resistance's are the same this could the be an alignment or bias issue.
You will need a mono recording with a 1kHz tone and then re- measure the output and try and adjust the bias to archive a balanced output.
I have a test disk with different test tones and when measuring the output i get 0.445/0.556 vrms
Tried aligment few times, i'm afraid the cart is the problem. I've read on internet few stories from different people who experienced the same imbalance on this specific cartridge.
I really like the sound of this Denon and i really want to balance somehow the channels.
On some recordings is not very obvious this imbalance but on some others is very annoying.
My player is a Rega Rp1.
Tried aligment few times, i'm afraid the cart is the problem. I've read on internet few stories from different people who experienced the same imbalance on this specific cartridge.
I really like the sound of this Denon and i really want to balance somehow the channels.
On some recordings is not very obvious this imbalance but on some others is very annoying.
My player is a Rega Rp1.
NEVER measure cartridges with an ohm meter - that sends a DC current through them... Ohh. Too late.
There are many factors determining the balance - the coil R is just one and not a very likely one. Geometry and symmetry of construction probably the most important, not much you can do about that.
Jan
I picked up a bunch of silver mica capacitors at an estate sale over the weekend. They're rated at 500V so a bit large, but I can make them fit on the board with a little judicious lead bending. Would these be suitable for Caps 2 - 6 & 9? If not, I have ceramic disk and monolithic caps. Would the monolithics be preferable to the disks?
Yes you can use silver mica but be aware C6 is no longer used in the latesc version.
One channel of my preamp is oscillating, tried to increase the output resistors from 47R to 100R and seems to be stable.
Is this a good solution to go further or maybe a small (50-100pf) ceramic cap would be a better solution.
While troubleshooting noticed the oscillation is gone with multimeter leads connected to output RCA connector.
Is this a good solution to go further or maybe a small (50-100pf) ceramic cap would be a better solution.
While troubleshooting noticed the oscillation is gone with multimeter leads connected to output RCA connector.