Diamond buffer headphone amp- can I parallel outputs?

[Fast Eddie D]

Originally Posted by dirkwright

Is this a diamond buffer ONLY with no loop feedback, or is it like the Sapphire with a voltage gain stage followed by a diamond buffer and a feedback loop around all of it?

It will have global feedback.

Since a CD player puts out 2Vrms, you don't need a voltage gain stage in your headphone amp. It can be just a power diamond buffer

I realise that. But I want it to work with my computer too. My computer could use some gain with some sources.

Do I read your post correctly that your headphone amp is going to have 6dB of gain?

6 dB of gain for the amplifier, with 3 dB insertion loss from the passive splitter, for a total of 3 dB gain. The splitter will have an insertion loss of 1 dB to the power amp, and will have a power amp mute switch. It will be designed for a specific application.

The circuit will be simple. It will consist of BD139/BD140 in a diamond buffer configuration, with a 5532 op amp front end and global feedback. It will have offset adjustments. The transistors will be mounted on one heatsink (one for each channel) to help with thermal stability. I will have to look through my junk to find a suitable transformer. I will build an active regulated power supply. It will have a simple analog volume control.

I am going to buy a mess of thse BD139/BD140s since they're so cheap. This will allow me to sort through a batch for better match and have some left over. I'm going to buy some extra 5532s too. You can't beat the prices for (hopefully) genuine parts.

[dirkwright]

Originally Posted by Fast Eddie D

The circuit will be simple. It will consist of BD139/BD140 in a diamond buffer configuration, with a 5532 op amp front end and global feedback. It will have offset adjustments. The transistors will be mounted on one heatsink (one for each channel) to help with thermal stability. I will have to look through my junk to find a suitable transformer. I will build an active regulated power supply. It will have a simple analog volume control.

I am going to buy a mess of thse BD139/BD140s since they're so cheap. This will allow me to sort through a batch for better match and have some left over. I'm going to buy some extra 5532s too. You can't beat the prices for (hopefully) genuine parts.

OK, that sounds good then. Good Luck!