Tape Head Rewire pics

[Scar972]

Leif
I've been slinging solder long enough. I certainly agree that connecting directly to the head terminals would have been more ideal. As I said in my original post, there just isn't a whole lot of info./pictures on how to do this especially if you've never done it before. Doc B. posted a few years ago that even some techs were having trouble with this. I started a thread on a different message board weeks ago looking for instructions on how to get directly to the head terminals, didn't get much. Care to share how the springs can be removed to get to the head terminals? I think it would really be helpful to some one down the road.

Thanks,
Anthony

 

[christensenleif@msn.com]

hello Anthony
not meant as critic though...
I used a thin 2 lead kapton insulated special cable with braided silverribbon shield I got from MTSL in Thessaloniki...It goes nicely throught the spiral hoses, so it´s just a matter of removint the top of the head house with the single Allen screw, lifting off the lid and then you´ve got access.....
I´ve completely rewired an A810, my 2 A80RCs and an A80R I sold to a friend.
just be quick with a hot thin tip on the head terminals
here´s the wire itself


here´s the headblock of an A80R getting rewired with the same cable
no wire hoses in this one...justed twisted the leads down to the headblock connector

 

[christensenleif@msn.com]

better pic of different gauges

 

[Scar972]

Awesome, thanks for all the pics Leif!
Would love to get my hands on some of those cables, was thinking of building my own using pure solid core silver.

 

[christensenleif@msn.com]

I guess Todor will sell you some.....
just mail to mastertapesoundlab
google and find his website...
but be warned...they´re a bitch to work with
I use a long sowing needle to pick the braid apart and a scalpel to cut off the kapton insulation
best
Leif

 

[jbazz]

Flux Magnetics Head wired with phono cable (same as supplied in some REED tonearms)
This exits underneath the A80 to King/Cello preamp

 

[Scar972]

Thanks for sharing, who wired your A80?

Leif
That does sound like a pain to work with, I think I’ll save myself the trouble.

 

[christensenleif@msn.com]

Thanks for sharing, who wired your A80?

Leif
That does sound like a pain to work with, I think I’ll save myself the trouble.

was worth it though.....

 

[jbazz]

Hi
I wired it myself. The cable manufacturer exposed the leads to my requirements. The free ground wire in the picture was eventually soldered to the shield enclosing the head to take care some hum issues.
Yes I'd say it was definitely worth it. Much better sonics with the Flux heads to King outboard amp compared to A80 electronics with repro card containing upgraded parts.

 

[Scar972]

Terrific job soldering those thin tonearm wires, I'd bet it sounds terrific with the Flux heads and King/Cello. Which made a bigger difference, the head upgrade or the outboard amp?

 

[jbazz]

Thanks, it was a little bit of a pain soldering the thin leads so i was not going to try different cables.
Yes it sounds great.
Sorry, I can't answer your last question. When i received the Flux heads, I went ahead and attached the phono cable. Never tried it with the Studer wiring. I wasn't very specific and should have said," compared to Studer head with A80 electronics.

 

[Fred Thal]

. . . measurement can't tell the difference
tony ma

Perhaps I’ve taken your comment out of context, but I hope you don't mean to suggest that the playback response of a tape system doesn't need to be carefully measured and adjusted.

I won't speak to the many prosumer and consumer tape machine brands popular with tape hobbyists, but when I see Studer equipment being modified for "head direct out" as documented in the pictures seen in this thread, it's rather disturbing, frankly.

Why?

Because it appears that people are not first taking careful measurements of the playback response of their machine’s stock playback electronics, before they start down a modification path.

It's hardly surprising that if you connect up someone's outboard tape stage to a repro head, it might then sound dramatically different.

But ask them for the graphs of both the original reproduce response and that of the new system (as we have done in another thread here) and they are silent.

Press them further and discover that they do not even own any calibration tapes.

So they have no way to actually know their tape playback system response.

It's embarrassing. Yet this has been going on for years and it illuminates the huge divide between knowledgeable tape professionals and many of the amateur tape hobbyists.

 

[Scar972]

Fred
I think we audiophiles went into the "head direct out" with the goal of bypassing the 40 years old internal electronics for something more current and built for audiophile use, this was the idea given to us when the tape renaissance began over a decade ago. While you criticize the state of the audiophile R2R hobby in many of your posts, what is your recommendation for the many who have already gone down this path to improve his/her tape playback? The products your company offer seems to be the cat's meow, but it's based on the A80 and A820, and not everyone owns these models. I'm sure your modified Studer A80/A820 are terrific but not everyone have the means to own one of your reproducers. Perhaps, there's enough room in the market for you and everyone else offering a tape preamp, and your way is not the only way. Offer a solution on the best way to modify for "head direct out" so that we all can learn from this. Be the solution, not the problem.

 

[Fred Thal]

I think we audiophiles went into the "head direct out" with the goal of bypassing the 40 years old internal electronics for something more current and built for audiophile use, this was the idea given to us when the tape renaissance began over a decade ago.

Yes, but you may have been sold a bill of goods by persons having no professional qualifications in the field.

The difficult part of achieving audiophile quality analog tape reproduction was never in the design of the playback amplifiers.

The difficult part is establishing and maintaining the system's time base accuracy. In other words, in the design and construction of the tape transport and its headblock.

The fact that some people have built a cottage industry based on the absurd idea that you can grab an old tape transport modified for head direct out and then connect it up to a purportedly audiophile quality "tape stage" should not legitimize their effort if their product cannot even be accurately aligned to the standard playback equalization curves. Consider that the very best designed phono stages will track the RIAA curve to within small fractions of a dB. As I have been writing for years now, we need an impartial, qualified equipment reviewer (one who knows how to make accurate measurements) to step up and peel back the curtain that's been hindering the verification of tape stage performance claims.

While you criticize the state of the audiophile R2R hobby in many of your posts, what is your recommendation for the many who have already gone down this path to improve his/her tape playback?

First, understand where you're starting from. Be aware of what you're doing and what your goals are. Learn how to recognize time base corruption (meaning both flutter and scrape flutter) by ear.

Then, quantify the time base accuracy of the transport you're using. Be sure to include scrape flutter in your measurements.

After you have a transport with good time base performance, you can measure the system's playback response in accordance with the equalization standards you're using. Only then can you begin to make meaningful evaluations about various tape playback electronics.

Offer a solution on the best way to modify for "head direct out" so that we all can learn from this.

I believe that I have been doing so for years now.

 

[dminches]

The fact that some people have built a cottage industry based on the absurd idea that you can grab an old tape transport modified for head direct out and then connect it up to a purportedly audiophile quality "tape stage" should not legitimize their effort if their product cannot even be accurately aligned to the standard playback equalization curves. Consider that the very best designed phono stages will track the RIAA curve to within small fractions of a dB. As I have been writing for years now, we need an impartial, qualified equipment reviewer (one who knows how to make accurate measurements) to step up and peel back the curtain that's been hindering the verification of tape stage performance claims.

I am confused. Not every phono cartridge is identical yet people have built phono stages with built-in RIAA curves and they seem to work. Why can't the same be said for tape stages? Is a tape head the equivalent of a phono cartridge? Why can't someone build a tape stage to be used with multiple tape heads. What am I missing here?

 

[Fred Thal]

Not every phono cartridge is identical yet people have built phono stages with built-in RIAA curves and they seem to work.

Yes, they seem to work. But to understand why they might sound different, you'll first need to measure their response with a specified cartridge.

Is a tape head the equivalent of a phono cartridge?

There are certainly similarities. For one example, they both have inductance.

Why can't someone build a tape stage to be used with multiple tape heads.

In the professional equipment sector, they can and they have. This equipment will have specific adjustments for accommodating a given range of repro head inductances, resonance frequencies and possibly also gap lengths.

 

[christensenleif@msn.com]

if I understand correct you said that the loading network towards the head must take into account the inductance
but since the inductance is gradually reduced by wear and (maybe) even more by relapping, this seems to be like hitting a moving target.
The A80 heads I have should be in excess of 200mH when new....how much reduction can be tolerated before one has to adress it in the loading network?
If I am correctly informed one relapping should result in about 60-80% of the initial inductance...of course depending on the initial wear pre relap...
best
Leif

 

[Fred Thal]

if I understand correct you said that the loading network towards the head must take into account the inductance
but since the inductance is gradually reduced by wear and (maybe) even more by relapping, this seems to be like hitting a moving target.
The A80 heads I have should be in excess of 200mH when new....how much reduction can be tolerated before one has to adress it in the loading network?
If I am correctly informed one relapping should result in about 60-80% of the initial inductance...of course depending on the initial wear pre relap...
best
Leif

Good thinking. But you can relax, as it's definitely not an issue in any practical sense.

The drop in the inductance value due to head wear (including relapping) over the usable life of a nominal 200mH Studer head will be less than 20 percent.

The main purpose of the loading network is to control the resonance peak (by altering its Q).

 

[christensenleif@msn.com]

ok good
thxs

 

[c1ferrari]

The main purpose of the loading network is to control the resonance peak (by altering its Q).

How is the resonance peak measured? Is it audible? If yes, can you describe/characterize it, measurement notwithstanding?
Would one find the loading network in the SHRO? What about write-only heads...would they benefit from a loading network?