Hi All,
Here's my first post on diyAudio after lurking for a looong time.
I've acquired one of those infamous Thule Audio IA100 with its associated TU100 FM Tuner.
Of course, the amp is toast, and that's why I'm here. It seems a lot of people here know this amp and have fixed it and made it reliable. A member called tiefbassuebertr, especially, has been very helpful to me with his previous posts, if he reads this, all I can say is vielen Dank.
The problem is that the power supply for the preamp (+-7.4V) and the digital (+5V), based on LM317/LM337 are poorly designed, they tend to oscillate / self-destruct and bring the rest of the preamp/digital control in their downfall.
I am rebuilding a separate regulation board, that takes the +-53V and regulate it down to +-6V (lowering this as +-7.4V was over the limit for some chips) thanks to a zener+transistor pre-regulator, then the usual LM317/LM337 suspects. DC and AC simulations were promising and I even ordered custom PCB's for this.
Question is: if you've owned this amp in its "stock" form, how reliable was it ?
If you've modified this (I know a few people did), what was your approach regarding the power supply improvements?
Of course, I am more than happy to share my re-designed regulation board. I even have spare PCB's if anyone needs it.
Thanks a lot for any insight.
Here's my first post on diyAudio after lurking for a looong time.
I've acquired one of those infamous Thule Audio IA100 with its associated TU100 FM Tuner.
Of course, the amp is toast, and that's why I'm here. It seems a lot of people here know this amp and have fixed it and made it reliable. A member called tiefbassuebertr, especially, has been very helpful to me with his previous posts, if he reads this, all I can say is vielen Dank.
The problem is that the power supply for the preamp (+-7.4V) and the digital (+5V), based on LM317/LM337 are poorly designed, they tend to oscillate / self-destruct and bring the rest of the preamp/digital control in their downfall.
I am rebuilding a separate regulation board, that takes the +-53V and regulate it down to +-6V (lowering this as +-7.4V was over the limit for some chips) thanks to a zener+transistor pre-regulator, then the usual LM317/LM337 suspects. DC and AC simulations were promising and I even ordered custom PCB's for this.
Question is: if you've owned this amp in its "stock" form, how reliable was it ?
If you've modified this (I know a few people did), what was your approach regarding the power supply improvements?
Of course, I am more than happy to share my re-designed regulation board. I even have spare PCB's if anyone needs it.
Thanks a lot for any insight.
Hi Paul
I did some repairs to my Thule IA 100 a couple of years ago.
please see
https://www.diyaudio.com/community/threads/thule-ia100-dc-on-output-when-hot.363092/#post-6451215
For the start of the process
I ended up making a separate power supply for the pre-amp with its own trafo, bypassing the resistors to the voltage regulators (LM317 and LM337).
I also added heatsinks to the voltage regulators just in case.
I agree with you that the input from tiefbassuebertr was adamant in this, but also the input from Rallyfinnen was invaluable.
The amp has now been running flawlessly for a couple of years
Attached some pictures how my installation looks
I did some repairs to my Thule IA 100 a couple of years ago.
please see
https://www.diyaudio.com/community/threads/thule-ia100-dc-on-output-when-hot.363092/#post-6451215
For the start of the process
I ended up making a separate power supply for the pre-amp with its own trafo, bypassing the resistors to the voltage regulators (LM317 and LM337).
I also added heatsinks to the voltage regulators just in case.
I agree with you that the input from tiefbassuebertr was adamant in this, but also the input from Rallyfinnen was invaluable.
The amp has now been running flawlessly for a couple of years
Attached some pictures how my installation looks
Attachments
check out this thread to the same topic (and a lot of internal images):
https://forum.mosfetkiller.de/viewtopic.php?t=64358
from this forum I haven't heard until now.
https://forum.mosfetkiller.de/viewtopic.php?t=64358
from this forum I haven't heard until now.