Hi again,
The new pair came, I installed them correctly in the correct single opamp slot. Guess what. They are making an oscillation kind of noise. Not like the first pair, that was pure electricity sound. This is a different thinner noise. Should I cut 8th or 5th pin?
The new pair came, I installed them correctly in the correct single opamp slot. Guess what. They are making an oscillation kind of noise. Not like the first pair, that was pure electricity sound. This is a different thinner noise. Should I cut 8th or 5th pin?
Does the PCB in the equipment itself have any connection to pins 1 and 8? In other words are pins 1 and 8 used in the original design?
.........but are they used in the original setup with the original OPA134. Without seeing a circuit diagram it is all guesswork 🙂 There are occasionally some weird designs out there that actually feed the input signals into the offset null pins. Can't say I've seen that done with an OPA134 but you have to be sure those pins aren't used in the original configuration.
Try unsoldering pins 1 and 8 on the socket and see if your OPA134 still works.
Hi again,
Good things happened. With the given information from Sparko's Labs, I inserted 0.1uf MKP capacitor between pins 2 and 6, all 4 Sparkos opamps started to work. (or should I say sing)
Here's the info: ". I think the best bet on this one is to try installing a small (100pF or so) cap from the output of the op amp (Pin6) to the minus input (pin 2) "
Even with this mod however, the user has to keep the volume pot at 12 oclock position when starting the amp, if not the amp oscillates. After the amp starts, it's possible to use the pot normally.
Thank you for helping. 🙂
#Gustard H10 opamp mod
#Gustard H10 Sparkos SS3601
#Gustard H10 Oscillation
Good things happened. With the given information from Sparko's Labs, I inserted 0.1uf MKP capacitor between pins 2 and 6, all 4 Sparkos opamps started to work. (or should I say sing)
Here's the info: ". I think the best bet on this one is to try installing a small (100pF or so) cap from the output of the op amp (Pin6) to the minus input (pin 2) "
Even with this mod however, the user has to keep the volume pot at 12 oclock position when starting the amp, if not the amp oscillates. After the amp starts, it's possible to use the pot normally.
Thank you for helping. 🙂
#Gustard H10 opamp mod
#Gustard H10 Sparkos SS3601
#Gustard H10 Oscillation
How much did they cost you delivered, and how big is the improvement compared to the OPA series chips?
And try a TL072 in place of 5532, may need circuit modification (input and output resistor change). Or a dual OPA series chip.
And try a TL072 in place of 5532, may need circuit modification (input and output resistor change). Or a dual OPA series chip.
The cost was 47 dollars for each opamp. The improvement was easy to hear. More bass, more treble and detail. Better instrument seperation.. I had made some mods to the unit, may be the difference was obvious because of that. I had removed a burnt blue 250v ac capacitor, replaced it with a wima mp30-y2 0.1uf (The change brought big difference and the part was cheap). Also changed 5532 chips with lme49722ma with an adapter, with 0.1uf 400v ero mkp at the +- pins.
I ordered 2x single to dual opamp adapter, for the other 2 sparkos opamps. I'm planning to leave one channel empty since I only use unbalanced inputs. I wish I had the courage and instructions to mod my Centrance dacport lx.
I ordered 2x single to dual opamp adapter, for the other 2 sparkos opamps. I'm planning to leave one channel empty since I only use unbalanced inputs. I wish I had the courage and instructions to mod my Centrance dacport lx.
TL 072 was about 35 cents here, and NJM5532 was about 70 cents (real original JRC).
Enjoy the sound.
Enjoy the sound.
I'm pleased you have found some sort of answer 🙂 but.... well there are lots of those but if it works......