Death of Zen 15 watt Power Amplifier

[KatieandDad]

My experience with Capacitive Multipliers has been disappointing.

I would recommend a decent CRCRC circuit rather than a C.M.

The impedance of the C.M. is quite high and can affect the frequency response of the amplifier.

[AndrewT]

Pd = Pmax * [Tmax - Tc] / [Tmax - T25]
using Pmax = 120W
Tmax = 150°C
Tc = Ts + 15Cdegrees = 70+15 = 85°C

The maximum power of the 3055 with a 70°C heatsink interface temperature is de-rated to ~ 120 ~ 65 / 125 = 62W.

Running the hottest part of the heatsink @ ~70°C effectively reduces your 3055 to a 62W device. Then you must de-rate for second breakdown at all the higher Vce imposed on the 3055.

Some 3055 have a Pmax of 90W @ Tc=25C.

[shaan]

Originally Posted by KatieandDad

My experience with Capacitive Multipliers has been disappointing.

I would recommend a decent CRCRC circuit rather than a C.M.

The impedance of the C.M. is quite high and can affect the frequency response of the amplifier.

My experience is the exact opposite.

I built the simple cap-multiplier in ESP site. Installed a 1000uF AFTER the multiplier as suggested in the webpage.

Result:- No hum, Excellent frequency response in DOZ, as if there is nothing but wires between the DOZ and the main PS caps.

Currently I use a simple CRC which gives the same hum-reduction plus bias-monitoring plus low-impedance. However, the multiplier was equally good, it just used extra components.

[shaan]

Originally Posted by AndrewT

Pd = Pmax * [Tmax - Tc] / [Tmax - T25]
using Pmax = 120W
Tmax = 150°C
Tc = Ts + 15Cdegrees = 70+15 = 85°C

The maximum power of the 3055 with a 70°C heatsink interface temperature is de-rated to ~ 120 ~ 65 / 125 = 62W.

Running the hottest part of the heatsink @ ~70°C effectively reduces your 3055 to a 62W device. Then you must de-rate for second breakdown at all the higher Vce imposed on the 3055.

Some 3055 have a Pmax of 90W @ Tc=25C.

Parallel 'em .

[AndrewT]

Originally Posted by shaan

Parallel 'em .

and/or reduce the Tc

[KatieandDad]

Originally Posted by shaan

My experience is the exact opposite.

I built the simple cap-multiplier in ESP site. Installed a 1000uF AFTER the multiplier as suggested in the webpage.

Result:- No hum, Excellent frequency response in DOZ, as if there is nothing but wires between the DOZ and the main PS caps.

Currently I use a simple CRC which gives the same hum-reduction plus bias-monitoring plus low-impedance. However, the multiplier was equally good, it just used extra components.

If you've got the parts, try them both. At the end of the day it will be you listening to it.

[shaan]

Originally Posted by KatieandDad

If you've got the parts, try them both. At the end of the day it will be you listening to it.

Yes. So let's stop talking about power supply as this is the DOZ thread. Peace.

Please Post DOZ Things Only. Thank you.

[KatieandDad]

OK - not trying to thread hop here.

The PSU is a vitally important part of any Class A amplifier project.

I'll leave it up to the builders to try what they may.

[shaan]

Thank you very much.

[kp93300]

Hi AndrewT
Thanks for your input.Your calculation is good but I am electronic illiterate.
Can you advice what is the optimum operating temp for the TIP 3055? The solution is to use a bigger heatsink or fan ?

Hi Shaan,
How to adjust the gain of DOZ ?

thanks

kp93300