Dinamid Construction : Planning Stage Questions.

[InSides]

Finally I have enlisted a friend to help me build a balanced Dynalo - alone I stand no chance of completing a working build. I was first going to have someone build me a Dynamight, but seeing we would get overboard with the cost of the thing, I decided to try and go with a Dynalo/Dynamid build, and decide whether I would care investing into something of a larger scale.

That said, I have a couple of questions with this - I have gathered a lot of excellent information of Dan Gardner's site, but I still have a couple of questions before I start sourcing the parts.

1. According to the docs on Dan's site, I would need two amplifier boards for a balanced Dynalo [two stereo boards for 4 channels]. Is this correct? At this point I have only one balanced source [E-MU 1212m] and would like to connect the Dynamid to that.

2. For the PSU, I guess a Dynahi PSU board configured for Dynalo use? Would I need two PSU boards also?

3. I want to include a loop out on the amp. How does one wire a loop out? Do you do it parallel to the input jacks? If so, would I only have the ability to include a balanced loop out? I would like to have both balanced and unbalanced loop outs.

4. Is it possible to outfit the Dynamid with Neutrik combo jacks, and use the amp with both balanced and unbalanced headphones? How does one wire those jacks? Would I have to have a switch of some kind?

Please note I am quite a newbie at this. Most of the building would be done by a friend who has built his own speakers and speaker amp, but I was hoping to have a few issues cleared out before we proceed.

Thanks.

 

[Tril]

I onw a Dynamid I built so I may be able to answer some of your questions.

1. Correct. 2 boards for a Dynamid.

2. I'm using a Dynahi PSU configured to output +16V, -16V. It works well. One is enough.

3. I don't understand the question. What's a loop out?

4. Maybe not what you are looking for but here is what I have done. I have four output connectors on the front. Two for unbalanced use and two for balanced use. Unbalanced : One 1/4 jack is connected with noninverted output and ground and another 1/4 jack is connected with inverted output and ground. Balanced : I have two 3 pins XLR jacks (one for the left ear, the other for the right ear).


Something you should think about is how you will adjust the volume. You will need two stereo pots. An option is to put two volume knobs on the front of the unit. One for the left ear and another for the right ear.

I did not do that. I used two stereo pots but I put only one knob on the front. Internally, I connected the two pots together with a belt and two plastic pulley. I'm regretting it because the tapers of two pots are not identical and the volume is adjusted differently in each ear. It's currently connected to the computer and I adjust the balance in software but it's only a temporary solution.

I would be interested to know how other Dynamid builder decided to adjust the volume (two stereo pots, quad pot, etc).

 

[InSides]

3. When talking about a "loop out", I was refferring to a "pass-through" connection, that would output a fixed level signal, so that I can position the amp in between my source and my preamp [driving my speaker setup]. I might also think about adding a "preamp out" [dependant on the volume control] and completely remove the current preamp from the chain. All in due time, though.

4. OK, not quite clear on this. As I understand it [and correct me if I am wrong], my source will output L+, L- and GL for the left channel, and R+, R- and GR for the right channel. For balanced output, I would wire L+ and L- to the left XLR, and R+ and R- to the right XLR.

Are you still using both 1/4" jacks for unbalanced use? What I wanted was the ability to drive one pair of balanced headphones, and two pairs of unbalanced headphones simultaneously. Like on the HeadRoom amps I mentioned. I definitely need more input on this.

Regarding volume, I was thinking of 2 x DIY stepped attenuator kits from DIYFidelity. Fairly cheap, and should provide for sufficient tracking.