change cap on my new ZX450 V2

[zorrobf2]

Hello, I need some suggestions about cap and if needed OPAMP replacement in my new (just buyed) ZX450 V2.
I find this replacement cap:

4 X 2200uF 16V with Nichicon HE 5600uF 16V UHE1C562MHD

but I did'n find a good replacement for 4 X 2200 50V in a nichicon HE series, who can suggest me a good choice fot them

I would replace also OPAMP but there are 20 (BA4560) in a crossover section and 4 (NE5542) outside crossover, can I replace BA4560 with OPA2604 and NE5542 with OPA2134 and if I don't use crossover can I replace only a part of them ?

Thanks in advance

[1moreamp]

Hello, I need some suggestions about cap and if needed OPAMP replacement in my new (just buyed) ZX450 V2.
I find this replacement cap:

4 X 2200uF 16V with Nichicon HE 5600uF 16V UHE1C562MHD

but I did'n find a good replacement for 4 X 2200 50V in a nichicon HE series, who can suggest me a good choice fot them

I would replace also OPAMP but there are 20 (BA4560) in a crossover section and 4 (NE5542) outside crossover, can I replace BA4560 with OPA2604 and NE5542 with OPA2134 and if I don't use crossover can I replace only a part of them ?

Thanks in advance

The Ne5532 are input and output buffer amps only so these are not critical devices to replace as there usage is very straight forward, I used OPA-2604's for these as my memory recalls, and I used OPA-2134P for the 4560 replacements as these are filter elements and such.

The OPA-2604 has distortion reduction circuitry built into the op-amp and this might interfere with filter operation, so this is why I did NOT used them where your trying to, but if you chose to continue in your direction I would love to see your results.
Will you be able to Scope the signal as it pass's thru to the main amp input ? I ask as this is somewhat important to make sure your not having issues after the swap out has been completed.

As for main rail cap upgrades your main issue is board space PG spent a fair piece of effort cramming all they did in that small space and replacement rated at 105 degrees C are a must, along with fitting the allotted space.
I have added 10,000 uf per rail by relocating them in the left window area on my old Ti-475 I had. The improvement was worth the effort. No more overheat shutdowns and a more solid bottom end. But this is my opinion, and not always agreed by others.

LMK what you think, and how your project works out....C

[zorrobf2]

I understand that I have to replace BA4560 with OPA2134 and NE5532 with OPA2604 but I have do change or modify other component as to support new kind of OPAMP ?

thanks

[1moreamp]

Well Yes,
on the ZX & Ti amps PG regulated the power supply very closely. I am sure without a doubt that the 15 volt rails are going to sag under the current loading these new op-amps will place on them.
< don't believe what you read in the spec sheets for the BB op-amps, they do draw more current than the stock parts, always >

R-51 and R-52 are fuse type 2.2 ohm resistors, and these are your current protection in the 15 volt rails. You might end up popping these open like fuses if the current draw exceeds there SOA spec.

Without a doubt your 15 volt rails will sag, how much remains to be seen. I just helped Bertje with the very same issue on a QX2350 amp he replaced all the op-amps in. He had to change the current limits in front of the simple zener diode regulator to get the rails up from 9 volts back to 15 volts. He swapped out 4741 op-amp for MC33079 op-amps and it sagged his rails by 6 volts DC.
Your ZX - Ti amp has a pass transistor based by a zener as its rail setup, so your results will be different due to the circuitry differences.....C

[zorrobf2]

Hi Cecil,
therefore after the OPAMP replacement I have to measure OPAMP power voltage to understand what additional action have to do? can you help me with detailed action because I'm not an electronic engeener?

I have soldering/desoldering station and a good multimeter but I don't have other equipement, I think that may be enought.

[1moreamp]

Hi Cecil,
therefore after the OPAMP replacement I have to measure OPAMP power voltage to understand what additional action have to do? can you help me with detailed action because I'm not an electronic engeener?

I have soldering/desoldering station and a good multimeter but I don't have other equipement, I think that may be enought.

Well if your rails sag and they will, you will need to lower R-51 & R-52 value equally until the 15 volt comes back. Now this is not without issues, as you are hoping not to exceed the Ic SOA rating of each pass element in each active regulator. So this not for the faint of heart, and careful thought needs to used to achieve reliable results. Then there is the extra heat on the sink caused by the extra load of the op-amps, I use a slightly higher volume fan to remove the heat.
If you getting the feeling this amp does not like this mod, well you are correct. This amp was never meant to do this to, but it is possible to complete successfully, it just takes a bunch of looking ahead and problem resolution and careful fore thought about what each thing does to the overall picture of things. Even SPICE modeling can't fore see every possible issue, but its a good start to use this prior to starting such a operation. SPICE is a engineering software tool that allows you to look at circuit design and interaction on a screen rather then real world, in hope of finding issues on the computer prior to building them real world.

I would NOT be undertaking op-amp changes without having access to a good O-scope to view the final signal with. You will be looking for instability and oscillation from any mismatch of op-amp to service use.
Op-amps just don't replace one another without some engineering thought about the differences involved within each device. Each Op-amp is designed and built different inside so how its going to work in any given circuit is a unique situation.
I have used the devices your now using successfully in several Ti products, and several MS and M series products. But that does not mean other parts in your circuits may not interfere with proper operation. If and when this happens you need a O-scope to track the issue to its source point and find resolution to the issue. I know of know other simple way to do this other that using a O-scope. I own 5 scopes so its a none issue to me......C

[zorrobf2]

Hi Cecil,
Unfurtunatly for me no O-scope no party, I will try to maximize benefit from all other mods (caps and so on). At my first turn on my new (this amp isn't in a great condition) ZX450 I have my firt negative impressione, it's true that I connected it only to test funtionality (before cap replacement) but it seems to be much noisy than my MS275, my approach will be

1) Replace all Power supply caps with better quality and increased capacity
2) replace all other Electrolitic cap with Elna Silmic II
3) Re testing amp to verify if problem is present

Can you suggest me action or component that could be checked for this kind of problems ?

[1moreamp]

Hi Cecil,
Unfurtunatly for me no O-scope no party, I will try to maximize benefit from all other mods (caps and so on). At my first turn on my new (this amp isn't in a great condition) ZX450 I have my firt negative impressione, it's true that I connected it only to test funtionality (before cap replacement) but it seems to be much noisy than my MS275, my approach will be

1) Replace all Power supply caps with better quality and increased capacity
2) replace all other Electrolitic cap with Elna Silmic II
3) Re testing amp to verify if problem is present

Can you suggest me action or component that could be checked for this kind of problems ?

Replace the gain pots abs bass boost pots and the crossover pots. Although most of these are located in feedback loops they can be a source of hiss and noise issues. Then there are three other types of noise possible.
1: fan noise ,< replace fan if need be>
2: Transformer noise < more difficult but try sealing the coils with some sealant that prevents to coils from ringing>
3 Electronic noise caused by worn out pots, bad caps,leaky transistors, and diodes.

LMK what you find, and I think you making a smart move by waiting on op-amp replacement until you have a scope available and are more versed with current limits in power supplies.

LMK what you find...C