[JHouser]

I love my mint. However, I’m curious to see if there is anyone out there interested in developing a design for a Dual Mono Portable. Maybe dual AD8610's and some Buf634's? Also to include a low/high ohm output switch for grado's and Ety's. I'm itching to try another portable DIY project. Is this of any interest to anyone?

(Please know I in no way intend to step on the toes of various beloved commercial builders who produce dual mono portables

)

 

[bg4533]

I think you may have misunderstood dual mono. Dual mono means seperate grounds for left and right along with seperate power supplies. To do this you need a source with RCAs, seperate batteries for each opamp and then to rewire your headphones to use a 4 pin means of connection. This will likely be far from portable.

I am guessing what you want is more like a miniature PPA. Basically you are just looking for single channel opamps instead of duals. Why don't you build it on protoboard? I am planning on building a stripped down portable PPA clone on protoboard. It would be nice to have boards made to use SOIC chips and stuff, but I have no design skills.

 

[bg4533]

I am not saying the PPA isn't portable, but with just some sacrafices that I personally wouldn't mind it could be a lot smaller. Design it around Panasonic FCs (2 C1s instead of 9), 1 buffer/ channel, drop out the other things I don't need, etc.

 

[JHouser]

Quote:

Originally Posted by bg4533 I think you may have misunderstood dual mono.

That's entirely possible. But yes, like a stripped down ppa. or like a MINT but with 2 8610's, a split power supply and bigger caps.
Quote:

Originally Posted by bg4533 Dual mono means seperate grounds for left and right along with seperate power supplies. To do this you need a source with RCAs, seperate batteries for each opamp and then to rewire your headphones to use a 4 pin means of connection. This will likely be far from portable.

Isn't that what a "Balanced" amp is? Not really interested in that.
Quote:

Originally Posted by bg4533 Why don't you build it on protoboard? I am planning on building a stripped down portable PPA clone on protoboard. It would be nice to have boards made to use SOIC chips and stuff, but I have no design skills.

I don't have a problem with that. But I would rather design something in eagle and etch it myself. That way I could get feedback from users who actually know what they are doing. Rather than creating a rat's nest!

 

[ppl]

Quote:

Originally Posted by bg4533 I am not saying the PPA isn't portable, but with just some sacrafices that I personally wouldn't mind it could be a lot smaller. Design it around Panasonic FCs (2 C1s instead of 9), 1 buffer/ channel, drop out the other things I don't need, etc.

OUCH so jou want go gut the PPA into somthing it is not might i sugest a pmeta or my Lisa II http://ipodstudio.com/forums/showthread.php?t=931 want dual mono just power each channel from a seperate battery. Dual mono dose not imply separate grounds for each channel a Dual mono Amp is a stereo amp with a separate power supply for each channel housed in one case. A bridge amp also knowen as BTL Bridge to load has separate grounds however may be powered from one power supply or separate power supplys
from this Link http://gamutaudio.com/philosophy.htm
i quote
"True Dual Mono.

Gamut D-200 and D 100 amplifiers are true Dual Mono designs, with two mains transformers, 2 rectifiers, and 2 pairs of large power capacitors. Some brands use just one mains transformer with two sets of windings, and still call it Dual Mono."

from this http://www.streetdreams.com/glossary/indexd.html

"Dual Mono Construction An amplifier construction configuration where virtually two separate single channels amps are used to comprise a stereo amp. Offers superior crosstalk rejection and channel separation.1

http://sta.graceland.edu/AV%20Terms.htm

"Dual Mono: Some amplifiers are designed to keep the left and right signals separate throughout the amp - this helps avoid possible interference between the two channels."

a BTL or bridge amp is discribed hear http://pdfserv.maxim-ic.com/en/an/AN1122.pdf
also see http://www.rexc.com/services/ohms.htm

 

[drewd]

Quote:

Originally Posted by JHouser Isn't that what a "Balanced" amp is? Not really interested in that.

Not exactly. A balanced amp has three conductors per channel: positive, negative and ground. The positive conductor carries the audio signal, the negative conductor carries an inverted audio signal and the ground conductor is...ground. The amplifier combines the two audio signals (it subtracts the negative signal from the positive) and outputs one signal and one ground per channel.

What you're exploring is, essentially, two single-ended amplifiers in one enclosure. Following the PPA or Pimeta topology, that would be two opamps per channel, one for signal and one for ground. Thus, you need a four pin headphone jack: left and right signals and left and right grounds.

-Drew

 

[bg4533]

Quote:

Originally Posted by ppl OUCH so jou want go gut the PPA into somthing it is not might i sugest a pmeta

What I want to build probably isn't really considered a PPA anyway. I could build what I want on the PPA 1.1 board. I want most all of the PPA features, but trading battery life for performance 1 buffer will do. It has been said many times that the PPA was designed for around 2000uF of rail capacitance. 1 or 2 Panasonic FCs can give what I need. I also really don't need bass boost or the extra set of Q3s. Most of what I want to eliminate in my opinion isn't what seperates the PPA from the Pimeta and the rest of the amps. I already have a few Pimetas here. I can't easily use Intersil buffers with them and I think they give up some of the nice features of the PPA. Pimeta size is more like what I want though. Sorry if my idea goes against the PPA design, but I have a feeling a lot of people might like a similar amp. I am not the person to design it though...

JHouser,
A balanced amp and dual mono amp require similar means to hook up headphones and sources. I might be a bit off in my terminology, but dual mono (and the Mint and most other amps) drives one channel of the headphone and has a ground. Balanced drives both channels, one channel is inverted.

I doubt the seperated chip idea would be all that beneficial. The powered ground of the Pimeta likely makes more of a difference.