Hi Guys
I have an Ashly XR1000 crossover that I generally like but would consider an opamp upgrade. It uses LT072s and other dual opamps. What would a be a good modern alternative for unity gain stability and active filters? t
they are all on dual sockets for easy replacement.
Thanks,
Scott
I have an Ashly XR1000 crossover that I generally like but would consider an opamp upgrade. It uses LT072s and other dual opamps. What would a be a good modern alternative for unity gain stability and active filters? t
they are all on dual sockets for easy replacement.
Thanks,
Scott
TL072 is a JFET opamp so I'd advise upgrading with JFET opamps. OPA1642 would be my prime recommendation. Probably you'll need an adapter PCB.
Not answering your question, but word of advice: Old layouts and fast modern opamps don't always get along nicely.
Swapping Op-Amps... you have checked to see it's stable haven't you ?
Swapping Op-Amps... you have checked to see it's stable haven't you ?
Putting high GBW op-amps into 30year old equipment can result in undesirable outcomes.
Here is an example of replacing a TL072 with a OPA1642
Here is an example of replacing a TL072 with a OPA1642
Crossover filters are designed around specific impedance levels to match the op-amp topology. Changing from bi-polar to j-fet or visa-versa is likely to degrade THD+N, so stick to the same type when rolling.
I presume you meant TL072, not LT072, which are j-fets; I'd probably use LM4562. If there are some bi-polar op-amps in there a different type would be needed, I'd probably use NE5532. The above two are very widely used in high quality audio gear.
Someone who knows more than me will hopefully jump in if necessary and correct me.
I presume you meant TL072, not LT072, which are j-fets; I'd probably use LM4562. If there are some bi-polar op-amps in there a different type would be needed, I'd probably use NE5532. The above two are very widely used in high quality audio gear.
Someone who knows more than me will hopefully jump in if necessary and correct me.
Hi guys
I read the posts and re-opened the unit to find the inputs are TL072s and the rest JRC 2043d which looks to be a decent opamps for the purposes. It looks like each opamp has ceramic disk decoupling near by.
I'm using the crossover at 300hz for the AE TD15s to the 18sound 6ND430 and I can dial in a very nice frequency response. I had one channel setup with passive crossover with huge parts and thought the active channel was a bit smoother but somehow was drawn to the passive side I think the td15s was a little louder than the 6nd430 giving mail vocals more depth. IDK. When setup both channels active, sound stage, imaging, detail and dynamics, tone are all excellent by me.
For most of my listening years the playback system had opamps only in the CD player. Whatever they are. I'm not opamp phobic it is easy for me to build those systems.
Am I counting angles dancing on a pin or is there something to be gained with the opamp swap out? It's easy and cheap enough to do.
Thanks again!!
I read the posts and re-opened the unit to find the inputs are TL072s and the rest JRC 2043d which looks to be a decent opamps for the purposes. It looks like each opamp has ceramic disk decoupling near by.
I'm using the crossover at 300hz for the AE TD15s to the 18sound 6ND430 and I can dial in a very nice frequency response. I had one channel setup with passive crossover with huge parts and thought the active channel was a bit smoother but somehow was drawn to the passive side I think the td15s was a little louder than the 6nd430 giving mail vocals more depth. IDK. When setup both channels active, sound stage, imaging, detail and dynamics, tone are all excellent by me.
For most of my listening years the playback system had opamps only in the CD player. Whatever they are. I'm not opamp phobic it is easy for me to build those systems.
Am I counting angles dancing on a pin or is there something to be gained with the opamp swap out? It's easy and cheap enough to do.
Thanks again!!
Unfortunately, OPA1642 is not available now. All sold out. I replaced TL074 with OPA1644 (4 ch). 3dB lower noise floor. I think it sounds better.
And right, the size is different (SMD).
Plenty of OPA2134s at Digikey. Expensive, worth it? Still only $75 for the whole project. Cheaper than one good coil these days.
OPA1641-1642-1644. Jfet inputs, reasonable bandwidth, low quiescent current, contained cost make them a reasonable swap for tl07x or opax134 but TI improved their common mode distortion quite a bit.
The only problem is that they don't exist in dip package, only soic/vssop.
edit: sorry didn't see plasnu's post. Availability will be a problem for quite a few modern parts :/
The only problem is that they don't exist in dip package, only soic/vssop.
edit: sorry didn't see plasnu's post. Availability will be a problem for quite a few modern parts :/
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Mouser showing stock of ISL28210, almost as good. But expensive, ~$6.
https://www.mouser.com/ProductDetail/Renesas-Electronics/ISL28210FBZ-T7A?qs=sGAEpiMZZMs94xRMzfQQ73EZxx%2FlXY4PCfN1YBsUTjo%3D
the soic dual channels opa1656 is maybe easilier avaliable and not so expensive for a try ? Need a pcb adaptator and so good decoupling cares
Replaced four TL 074 with LT 1058 many years ago in my VMPS crossover. The result was very good. The dual version of the opamp is LT 1057 but they may be obsolete.
TL072 are an ancient design that's noisier and has higher distortion than anything used these days. The OPA2134 would be a much better DIP8 drop-in, so no need for an adaptor. For the old 2043s I'd probably drop in LM4562s.
I realize that the OP has made his purchase, so hope it works out!
OPA1652 (forgot the relaxed DC offset spec part # that's even less expensive) would also work as a decent replacement for the TL072, as it's still very high input impedance (MOSFET vs JFET).
That said all the caveats about decoupling these much higher GBW parts stands. You will want to double check that they're not oscillating, as sometimes a layout or topology can tip your stability.
The BJT input gives you a few options. I honestly doubt you'll hear much, unless you have an oscillating circuit (component age changing filter/etc) and get rid of it, or vice versa.
OPA1652 (forgot the relaxed DC offset spec part # that's even less expensive) would also work as a decent replacement for the TL072, as it's still very high input impedance (MOSFET vs JFET).
That said all the caveats about decoupling these much higher GBW parts stands. You will want to double check that they're not oscillating, as sometimes a layout or topology can tip your stability.
The BJT input gives you a few options. I honestly doubt you'll hear much, unless you have an oscillating circuit (component age changing filter/etc) and get rid of it, or vice versa.
There's a sleeper opamp out there you need to try. It has laser trimmed offset, jfet inputs and bipolar outputs. I had a project that was eating expensive op amps left and right, primarily the TI Excalibur series. I found this cheap alternative and liked it better! LF411.