Intact Audio

I'd likely start with something similar to the last schematic in that thread I linked. The video op-amp in the first schematic is probably asking for trouble. Use 75ohm BNC connectors for the external interface and proper 75ohm cable. Bypass the relay on the input board and the pulse transformer and...

Hi Dave, I'll need to do all six output channels of this thing - I'm using a 1 inch compression driver as a tweeter. Not sure if it would be better to do them one pair at a time and use caps for the time being in the other channels. Do you think there will be a learning curve? The current crossover ...

dave slagle wrote: any suggestions for the input circuit? I simply hacked the input in and it sounded good.

Something like what is discussed here is where I was going to start:
http://www.diyhifi.org/forums/viewtopic.php?f=2&t=1191

Sitting here listening this evening... Where do I send my money? I need a master attenuator solution too. I've got this sounding pretty good, but I know it could be lots better.

Hi Jeffrey, The digital input circuitry should maintain the 110ohm characteristic impedance of the AES/EBU digital standard. This is nearly impossible to do with the connectors used and then there is the relay that switches input A between analog and digital. This screws up the reflected impedance a...

I'm not opposed to removing the entire output PCB from the unit in order to get the transformers in there. Would need to redo the input section, but the digital input circuitry is awful and should be redone anyway.

Hi Dave, What's the size of the transformers used? No chance of them residing inside the DCX case, I suppose. I bought the DCX for tweaking, but the convenience and the delay feature make it likely to be relatively permanent. What do you need to know about the system to get this happening for me? I'...

Anonymous wrote:So where can i get the real one from then?

NOT fake unless someone has assumed Martin's identity!

nt

I have a current output DAC that has an output impedance of around 50ohms after the passive I/V and passive third order output filter. As I want to use all valves for gain stages after this point, I'm wondering about attenuating at this point since getting this low impedance later on is going to cos...

The preamp has gone to its new home. A little stint on the scope showed me that this trans is a 16:1 impedance ratio, so I was getting a gain of exactly 5x. Some observations: With 10Vrms across them, the autoformers were rather like tiny speakers. While it still sounded great to me, I think the hig...

Man, I stuffed that up. I had it in my mind it was an 8:1 voltage ratio that was specified. If it's an 8:1 impedance ratio, well, that's an awfully light load for a 6SN7 type, but it makes a hell of a lot more sense than the 64:1 impedance ratio my thinking was giving me. I suppose the light loading...

I just noticed the transformer used is specified as having an 8:1 turns ratio. I had assumed it was a 10K:600 unit, which is more like 4:1. This means the preamp gain is 2.5X and the secondary volatge is 5Vrms, but that doesn't sound right. It seems like more gain than that to the ear. I'll have to ...

Thanks for the reply Dave. what is the overall gain of the linestage? and where are you listening on the autofomrer? (attenuation wise) Gain of pre is around 5X. Probably listening with a little too much attenuation, maybe -30db? There is probably enough gain in the system without the pre. i have ex...

Hi Dave, I just built up an Ultrapath style preamp WOT (Electraprint outputs - 7193 tube) for a guy here and have it playing in my system. It didn't sound anything special until I had the idea to run it with the DACT 100K input attenuator wide open and use my AVC on the output. Once I set it up that...