re: d44
probably a bit late with this but, d45 pnp is complement to d44 npn. you can use tip29 and tip30 also.![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
billg here hi all:i was chking the d40/d44 transistors for a crown dc300a-the d44c7,8,9 are rated at supply volts of 60v.but the d40 comes up as an darlington..the data sheet specs the compliment at d44c7,8,9 same specs as the npn.thought i would add this.
probably a bit late with this but, d45 pnp is complement to d44 npn. you can use tip29 and tip30 also.
Hello guys,
I would like to pick your collective brain regading this topic again.
The circuit I have here is this
It´s from a Brazilian version of the Kenwood KA-501, named CCE SA-6060.
And remembering ua749 architecture
Well, I am a little bit rusty in my electronics, but it seems that LAG IN/out are not really being used, just not left open, right ?
So, if I would try and use something a bit more refined, would a NE5532 be a step up ?
Obviously it would not be pin compatible, but I could plug in an external pcb.
Should I also modify something in the original circuit, besides removing those 2 caps and resistor from pins 2-4 and 10-12 ?
Would it be necessary to increase/limit current or something like that ?
And if I would like to use OPA 627/637 ?
Thanks in advance for any thoughts.
I would like to pick your collective brain regading this topic again.
The circuit I have here is this
![ua749-1.jpg](https://i.ibb.co/LxzCsjf/ua749-1.jpg)
It´s from a Brazilian version of the Kenwood KA-501, named CCE SA-6060.
And remembering ua749 architecture
![ua749-2.jpg](https://i.ibb.co/0cK312q/ua749-2.jpg)
Well, I am a little bit rusty in my electronics, but it seems that LAG IN/out are not really being used, just not left open, right ?
So, if I would try and use something a bit more refined, would a NE5532 be a step up ?
![ua749-3.jpg](https://i.ibb.co/zHYYDKf/ua749-3.jpg)
Obviously it would not be pin compatible, but I could plug in an external pcb.
Should I also modify something in the original circuit, besides removing those 2 caps and resistor from pins 2-4 and 10-12 ?
Would it be necessary to increase/limit current or something like that ?
And if I would like to use OPA 627/637 ?
![ua749-4.jpg](https://i.ibb.co/qBxX5Pb/ua749-4.jpg)
Thanks in advance for any thoughts.
Last edited:
Do you still have some ua739? I need 12.I found about 50 ua739 FAIRCHILD, still in the original cue ... they are available to sell individually or in pairs
.... it seems that LAG IN/out are not really being used, just not left open, right ?....
Looks to me like both clamp internal points to control response for stable feedback.
And that with this custom compensation, performance is better than any "universal" opamp of the 1970s.
And the tone-control amplifier is usually not a major hit on sound quality.
Is there actually something wrong with it as-is?
- Home
- Amplifiers
- Solid State
- ua739 Op Amp Replacement