Technics RS-1500 upgrades

[KevO]

Hi,

I just signed up for the TP after the great demo at Bob Hodas CAS room. I've been planning/saving $$/thinking about it since the 2011 CAS demo.  I acquired a lightly used RS-1500. I ordered the tape path kit from Bottlehead and an Eros kit too.

I have funds left to get the extended response playback head and plan to drop off the head block at Flux Magnetics then take deck to a good tech for mod installations, CLA, etc.

Questions:

Are dummy heads a good idea? Will they keep tape wear to a minimum vs leaving the old heads in place? Old heads look fine.

When the ERP head gets wired to the new output jacks, is the connection direct from the head or do you use the Technics PCB on the head block? Any documentation/photos available?

Also, I have not powered the deck up yet. I have no idea how many years it has been stored. Should the tech use a Variac to power it up or should I plug it in and hope for the best?

Any way to have new head switch between direct out and tape repro? I understand it may be nice to have the meters active for alignment, etc.

So many questions.... first RTR I've owned.  Hope my questions make sense. All suggestions welcomed.

Thanks - Kevin Olson

[ironbut]

Hi Kevin,

Welcome to the forum!

Regarding the dummy heads, for absolute performance, you can get some small improvements.

You'll find that moving the tape through the machine and across the playback heads with the least amount of friction, at a constant speed/tension and having the shortest distance between the head and the nearest supports is what it's all about as far as the tape transport goes.
Dummy heads are designed to be long lasting and support the tape with the least amount of friction. The erase/record and extra playback heads are designed to do their individual jobs all of which requires a larger contact patch with the tape and are generally make with a softer material.

The obvious drawback to using dummy heads is if you should ever decide to record or playback 1/4 track tapes (most of the tapes you see sold on auction sites are 1/4 track).
I have the Flux ER head installed on mine but I have a collection of all kinds of other tapes that I listen to so I've kept the other heads in place.
If you should decide to do this, I suggest that you have your heads and guides serviced (maybe lapped) at the same time as when you have the Flux head installed. If Greg can't do that for you, John at JFR can do the whole thing for you. They're buddies so either way is good for Greg.

A very worthwhile upgrade to these machines is the Bottlehead tape path upgrade. When I installed it on my deck, I was shocked at the improvement in the high frequencies. If you're taking your machine to a tech, that would be the time to have that installed (pretty simple).

Regarding a switch from the heads, I don't find the idea very practical and could degrade the sound. The reasons I don't feel that it's useful is I don't trust the built in meters for calibration and once you've heard the huge difference in sound using any of the outboard electronics available today, you'll never go back (night and day).

One alternative is to find a spare headblock and leave it stock and have "the works" done to the other. That way you can have your cake,..

If you're a beginner, it would be a good idea to check out the "Beginners Guide" which is located in a sticky on top of the General Forum. It will give you a basic understanding of tape and tape machines and is a good place to start.
There's also a gazillion posts regarding RS1500 machines if you use the search button.

http://jrfmagnetics.com/

http://www.bottlehead.com/

Hope that helps and enjoy the journey!

[docb]

Generally, dummy heads are installed to assure the proper tape wrap around the heads on either side of the dummy head by maintaining the original geometry of the tape path. Dummy heads can be made of materials that are less prone to wear. They can be a cost effective way to replace a worn head that you might never use. For example if you only use the deck for playback you could replace worn and grooved Technics permalloy record and erase heads with dummies made of a harder material.

[KevO]

I can think of one other advantage for the dummy heads.

Replacing the erase and record heads will prevent me from being a dummy and ruining a TP tape!

-Kevin

[ironbut]

Luckily, on most machines (Technics included), there's a "fail safe" to prevent recording over prerecorded tapes.
Not only do you have to push the "record" and "play" button at the same time, but the 2 "Record Mode" switches have to be in the "on" position.

Regarding your previous question about having the ability to toggle between internal and external playback electronics, I just posted something;

http://www.tapeproject.com/smf/index.php/topic,2429.0.html

[Listens2tubes]

Steve, this is the first time I've seen the linked post. SWEET! So on a modified for external preamp machine, really all you need is a pair of RCA jacks to feed the original playback amps on the back of the deck. Meaning, the "flying leads" from the heads could be plugged into my Eros or into the RCA sockets marked "amp inputs" on the back of my deck. YES!!!!

[ironbut]

Hi Neal,

Yes, as long as those extra RCA jacks feed the stock signal path.
So, for example, on my Technics, the 4 wires I disconnected from the headblock connector (replaced by a new set of wires going directly to a pair of RCA's on the back of the machine for a direct output for my Tube Repro) could also be routed to the back of the machine and soldered to another pair of RCAs. They would be the input to the stock electronics. A pair of short jumpers (only need to be a couple of inches long in most cases) would go from the "direct out" to the "stock electronics input" restoring the stock signal path.

[KevO]

I have the Extended Response Playback head installed now (thanks Greg), so waiting for Eros and Tape Path Mod kit. Once they have arrived, I will build the Eros and send deck out for Mod install and Clean Lube Adjust.

During CLA, what else should I have done to the deck? Obviously, install Mod Kit , head align and bias. Anything else?

Would it be beneficial (IYHO) to replace ERP head wires with new, better wires? I have some VH Audio double shielded wire and new female RCA jacks. I bought some VH silver coax wire to make cables from the Technics to the Eros and I ordered extra. I realize this means removal of capstan and flywheel. If tech is already in doing brakes, how many more hours to rewire?

I saw Docs photos of the easy way to wire the head to the OP jacks, just wondering if once someone is disassembling it, would this be worthwhile to rewire? I know this is subjective, but my view is in for a penny.....

I could do what Doc has outlined  in 'Tapping the Headstack' myself. But that 70's wire looks.... old. Did Doc rewire the head when mods were done at Bottlehead?

Thanks!
Kevin

[docb]

We used the stock head cables when we did the mod on Technics and Otari decks. There's a lot of EMI in a deck what with all the motors. Some types of cable are better than others in terms of hum rejection from magnetic coupling, and chances are the manufacturers picked a cable that was optimal for the given deck. That said, you could certainly experiment with a bunch of different cables and come to your own conclusion. IIRC Technics used shielded twisted pair and I think Otari used coax, but it has been a while since I worked on one.