Another 5050 question.

[nh36000]

I wrote in about a head stack some time ago but didn't find the thread it's in, so, a fresh post, here. I bought a 'like new' head stack recently.

I put the 5050 up on the bench and recorded a 1K signal. I found that the channels are EXACTLY, 180 deg. out of phase.

Odd, so I put the cal. tape on and saw the same thing. 180 deg. out of phase.

So here is a question I'd like to ask, of someone who knows these decks better than me.

Is the white wire coming. from the back of the heads, being used as ground? I've got an idea that the two Pb heads, each, have 'hot' leads wired in, to ground instead. What else would throw polarity off, like that?

Write back, if you can, please.

BTW; As seem on a scope, that, out of phase, is perfect. Dead on it. Those two signals cross at Y= 0. Someone did a good job of lining it up, but!
Lu.

 

[nh36000]

The latest!

In thinking about this after writing, I'll compare this stack with the original stack. And I know all ready, that the Pb heads are wired into the board, the other way around.

Lu.

 

[nh36000]

Well, in the end, I switched the brown and white leads of the Pb heads around. It's plays in phase, now. If I ever part with this head stack, I'll have to put them back the way they were.

Apparently, Blls are wired up differently that a straight 'B' is. I had no idea it would do that.

Lu.

 

[Skylab]

Wow, that is very odd. Good you figured it out though. Very nice deck the 5050.

 

[nh36000]

Skylab;

Yes, it was a eye opener to me, too. A nice deck, indeed, the best sounding of all.

In my studies of DC offset in amps, I discovered that the least possible DC voltage, to your speakers, is the ideal. AC signal will push the speaker cone in and out to produce a sound. Straight DC will push the speaker cone either in or out and hold it there. So, the best place for DC voltage, to the speakers, is where the cones are as close to the place they're at, when the amp is off. If your DC volts is pushing the cone out, the travel in the out direction is squelched, a bit. So, right in the middle is the best place for it.

Now, with the re wiring, I don't know if the speaker cones are going in or out, on the plus side of the signal. But, it does reproduce in phase, now.

I'm going to need to settle on the fact that 'good enough is good enough'.

Lu.

 

[sdw54]

Were you monitoring the signal out of the recorder XLR outs? The Hot and Cold pins are reversed on these units. When I installed the Otari's in our new studio we had out of phase problems until we found out the pins are reversed from the manufacturer. Easy fix. Otherwise, they are great, bullet-proof decks! Used them for 10 years in a syndicated radio studio.

 

[nh36000]

sdw54;


A little history first, here. You seem to know what you are talking about, but I am fairly new to 5050s.

The first post told of me buying a head stack. It's for a Bll and I put it in a B-2HD. An earlier model. I plugged it in for 15 minutes just to test it, and put the originals back in, after that.

With a power amp and pre, I thought I didn't need an external amp. I've looked into balanced and unbalanced XLRs and think that it's fine the way it is.

I also have adapters plugged into the back and I am using RCA interconnects. Skywave has written to say, get rid of the adapters in favor of XLR/RCA patch cords. Some time down the road I will do just that.

My cords from the deck to the pre are only three feet long so I don't think I need balanced XLRs. That may or may not be true, Again, I'm new to 5050s. Otherwise, I have Sonys and TEACs.

How's that? Asking, in your experience, what do you think.

Lu.

 

[sdw54]

nh3600,
Sorry for the late response. Realistically, there shouldn't be any difference between an early and later head stack assembly as far as phase is concerned, Generally they should be a direct replacement. If you are using it in a home system, I don't see a problem unless the phase is 180 degrees off between the 2 channels. My problem regarding phase was due to use with other equipment where you were using more than one source/tape machine to create a track; i.e.mixing from multiple sources. For recording and listening purposes it should be fine. Enjoy your deck!
Scott

 

[nh36000]

Scott, there you are:

As an answer to your quest., I'll say no, there isn't anything else in the system for my recording. I'm not in the habit of recording equalized or processed signals.

I source re-ish' records and 15 IPS protection copies but they go through the pre amp and right into the deck, then. I have DBX units and Eq'ers, and considering path, they are in there behind the decks. I can listen to processed recordings but I don't record them that way.

There is a pair of red and white wires to one channel and a pair of brown and white wires on the other channel, to each of the Pb. heads. I turned the 'b&w' wires around. Pardon me.

My first thought was that the stack was wired up wrong. And from what you wrote, that might be the case.

Funny,

Lu.