Problem solver???
Pro Audio Gear: ARTcessories CLEANBox Pro Dual Channel Level Converter
Marshall.
There is a lot of talk about how to wire the DCX for unbalanced. Tie 3 to ground, leave 3 open, tie 3 to ground via 10K, 20K, 50K and others. I've tried them all.
What actually worked by far the best for me was a transformer on the XLR output. But of course that was the biggest, heaviest and must expensive option.
Your balanced resistor attenuator should work well. Let us know!
Problem solver???
Pro Audio Gear: ARTcessories CLEANBox Pro Dual Channel Level Converter
Marshall.
Opinion is only as valid as its verifiable supporting evidence.
Not if freq response/bandwidth is a concern. The posted specs are BS, many folks have measured the clean box and it has no business in a "hifi" system.Originally Posted by mah
Just my .02......................... i'm sure someone here will think it's wonderful.
Not all vegetables make good leaders.
Is there something that does the conversions but of suitable performance?
Opinion is only as valid as its verifiable supporting evidence.
Good question. The attenuation isn't a big deal, but the level shift up for the input is nice. It's what a preamp should do anyway.
Are you sure your preamps don't have enough gain and headroom to run a strong signal into the DCX? Can you measure? Or look at the input meters on the DCX? If you need a reference level tone, we can get you one.
I have found some relevant material on the net which I will post tomorrow for comment.
My amps, Sony 1120(made 1965-1968) and Sony Vfet Ta-4650(1974-1978), were both Hi-End, low-noise models in their day- definitely pre CD, definitely 1V out/in @ pre/main.
As I said, previously, I am a bit of a Luddite. Used Classic gear at budget prices also suits my level of disposable income. Buying a dcx3400 would be a big deal for me, so I want to get it right.
Until the morrow, Marshall.
Opinion is only as valid as its verifiable supporting evidence.
Honestly, you don't want anything active between the XO and power amps.
It is extremely cheap to wire in your own resistors in an attenuator and wrap it up like the Endler attenuators do. You can use some cheap slider pots until you get the appropriate levels and then pull the pots and install fixed values for your application. I paid between...I think 65-75 for each attenuator but he custom made them, used top notch components, did very professional work. If I was interested in price, I could have done this easily...and I think so could everyone here with a little soldering skill. Transformers work...but I thought only attenuation was needed not isolation. Depending on the amp you feed...maybe this has merit. But resistors are the cheapest route.
Yeah, I like Steve's idea. Use pots to find were you need to be then replace them wit fixed resistors.
So you think the Sonys don't have any gain in the preamp circuit, yeah? Could be. Some of my vintage Pioneer and Sansui gear was like that, the pre outputs were really just after the selection switch. Volume, gain and tone were downstream. Too bad.
You kinda-sorta need a preamp to drive this rig. It would have input selection, gain, volume and any other gadgets. The output of that would go to the DCX. Or am I misunderstanding you signal flow?
OK Marshall, I went back and reread you posts in this thread.
Steve Summed it all up beautifully in post #11. Here is a good quote.
What I'm not sure about is this:
OK, is the pre-amp out actually volume controlled on this amp? Have you checked? If it is, it probably also has gain, maybe 10dB, That's good and will help you with Steve's point #1. If the preamp outs are not variable, you'll need a preamp that has that.
Steve's point #2 will be taken care of with your other amps because they have a volume control. So you can run a hot signal thru the DCX and turn it down at the amp. That's ideal.
Click on this link then click the TA 4650 download link for the service manual. Pages 2,3 & 4 have the specs and cicuit block-diagram. There is only one volume control and it is in the pre-amp section.
I think it is worthwhile to proceed with purchasing one of the crossovers to place directly in the pre-main loop.
If it is noisy I can boost the input to the crossover with a matching-amplifier or matching-transformer and then attenuate the crossover output passively. Am I correct?
Marshall.
Opinion is only as valid as its verifiable supporting evidence.
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