Just a correction of nomenclature: it's "closed loop, dual capstan" (CLDC).
Phase locked loop is an electronic circuit and unrelated.
Yes the felt pressure pad can deteriorate but even at its best it's inferior
to controlled back tension because it induces possible scrape flutter, and
wears the head more quickly, and more unevenly, resulting in poorer
playback. A pressure pad might be useful once in a while in improving
tape-to-head contact in a creased tape.
Speaking of "one less thing to go wrong with the playback chain", in a
playback only situation, both the erase and record head are superfluous and
are only more surfaces to attract tape gunk and stiction. In my playback
only Naks I remove the erase and record heads. It's easier to do so in a
cassette deck than a reel to reel machine as those heads dont play a part in
the tape path geometry for the playback head and so no other mods are
needed. For playback only situations, more useful than "two head" or "three
head" is "one head".
Tim
----- Original Message -----
From: "Steve Greene" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, April 02, 2018 9:28 PM
Subject: Re: [ARSCLIST] Sticky shed - clogged heads?
> The feature that many Nakamichi's had was called "phase locked loop" dual
> capstan. Essentially it relied on the two capstans, in phase to maintain
> proper tension, which obviated the need for the felt pressure pad, which
> was lifted out of the way of the playback path. That amounted to one less
> thing to go wrong with the playback chain.
>
> It was even more important to clean the rubber capstan roller regularly,
> since glazed rubber surface could often cause the tape to drift "off
> path".
>
> Steve
>
> Steve Greene
> Audiovisual Archivist
> Nixon Presidential Library and Museum
> National Archives and Records Administration
> (301) 837-1772
>
> On Mon, Apr 2, 2018 at 3:49 AM, CJB <[log in to unmask]> wrote:
>
>> Again thank you guys. How can I lubricate said cassette tapes please?
>> What is the process? Getting tape head cleaner is a problem too since
>> the demise of VHS and cassettes and reel2reel tapes. Is it ethyl
>> alcohol? Maybe eBay has it? Huh - cotton buds are easy to get - even
>> though they are mainly of plastic. BTW right now the weather is damp
>> and raining with high humidity. Maybe I should put the cassettes in
>> front of a hot air heater? I have a brand new top of the range
>> (ex-display) Technics dual cassette player arriving next week. Chris
>> B.
>>
>> On 01/04/2018, Corey Bailey <[log in to unmask]> wrote:
>> > Hi Chris,
>> >
>> > First of all, DO NOT use your microwave for any type of tape
>> > restoration. This has been tried and the results are disastrous.
>> > Second,
>> > do not use any kitchen appliance, that is used for food, for baking
>> > audio tapes. The baking of audio tapes produces out-gassing that should
>> > be considered as toxic.If you are going to consider baking the
>> > cassettes
>> > in question, you will need to invest in a device that can be dedicated
>> > solely to that task. A food dehydrator will work fine but know that
>> > there is a learning curve. Research the process. The information is out
>> > there. I have written an article about baking audio tape which is
>> > posted
>> > on my website under "Useful Information." I am not a fan of baking
>> > audio tapes. I use the process as a last resort. First, I will try
>> > lubricating the tape and for cassettes, I have a transport that I have
>> > modified (hacked) for this procedure. That said, Marie O'Connell posted
>> > that she has successfully baked audio cassettes. So have I and many
>> > other qualified personnel. So, obviously, it's possible.
>> >
>> > Cheers and, Happy Easter!
>> >
>> > Corey
>> >
>> > Corey Bailey Audio Engineering
>> > www.baileyzone.net
>> >
>> > On 4/1/2018 1:11 AM, CJB wrote:
>> >> Hi guys. Thanks for the heads up. The cassettes are off-air recordings
>> >> many from the 1970s from Long Wave / Medium wave and some FM. They are
>> >> Beeb airings - likely all long since deleted, wiped or junked. These
>> >> are the only recordings extant. It is important to rescue the
>> >> contents.
>> >>
>> >> The situation started after a few cassettes had gone though. The
>> >> C-120s seemed OK. I then decided to process the C-60s first: Ferro,
>> >> Scotch and BASF. I had two cassettes loaded. Huh - I fell asleep and
>> >> the first started all over again. When I checked the digital file -
>> >> using Audacity - I found that the first was nearly perfect first time
>> >> round - but then when it got repeated the sound level was not only
>> >> lower but it was also muffled. I used a tape head cleaner and tried
>> >> again, the sound came back as loud as it should have been, but then
>> >> quickly deteriorated.
>> >>
>> >> I'm not sure that I can retrieve the situation. It seems that the
>> >> tapes are shedding and clogging the heads badly. I am nervous about
>> >> baking - I only have a microwave!!
>> >>
>> >> Issues with azimuth lining is rather too advanced for the project
>> >> which is more one of rescue rather than faultless archiving.
>> >>
>> >> Chris B.
>> >>
>> >>
>> >> On 31/03/2018, Marie O'Connell <[log in to unmask]> wrote:
>> >>> I have had good success with baking cassette tapes suffering from SSS
>> >>> and
>> >>> the brands are random. Keeping the heads clean is paramount.
>> >>>
>> >>> Like Steve, re-housing the cassette can help along with renewing the
>> >>> slip
>> >>> sheets. As a matter of course I check the felt to make sure it's
>> >>> intact.
>> >>>
>> >>> Happy Easter!
>> >>> Marie
>> >>>
>> >>> On Sun, Apr 1, 2018 at 8:23 AM, John Haley <[log in to unmask]>
>> wrote:
>> >>>
>> >>>> I am not recalling exactly what I paid for the Nak Dragon, but it
>> >>>> was
>> >>>> something like $1100. I bought it on Ebay and got lucky--it is in
>> >>>> flawless
>> >>>> condition.
>> >>>>
>> >>>> The Nak Dragon is missing one desirable feature--there is no speed
>> >>>> control. But it is rock-steady with moving the tape--probably
>> >>>> getting
>> >>>> rid
>> >>>> of the tiny bit of friction of the tape pulling past the pressure
>> >>>> pad
>> >>>> helps. It has a piece that pushes back the pressure pad so it is
>> >>>> out
>> >>>> of
>> >>>> the way, and tape tension against the heads is provided by the
>> >>>> closed
>> >>>> loop
>> >>>> dual capstan design.
>> >>>>
>> >>>> Best,
>> >>>> John Haley
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>> On Sat, Mar 31, 2018 at 1:57 PM, Steven Smolian <[log in to unmask]>
>> >>>> wrote:
>> >>>>
>> >>>>> If I remember correctly, the NAK draws the tape away from the pad,
>> >>>>> bypassing
>> >>>>> it.
>> >>>>>
>> >>>>> For what it's worth, I've found the slip sheet inside the cassette
>> >>>> housing
>> >>>>> will exhibit signs of sticky shed.
>> >>>>>
>> >>>>> One answer is to rehouse each cassette into a new shell. I've done
>> >>>>> that
>> >>>>> many a time.
>> >>>>>
>> >>>>> Steve Smolian
>> >>>>>
>> >>>>> -----Original Message-----
>> >>>>> From: Association for Recorded Sound Discussion List
>> >>>>> [mailto:[log in to unmask]] On Behalf Of Lou Judson
>> >>>>> Sent: Saturday, March 31, 2018 1:02 PM
>> >>>>> To: [log in to unmask]
>> >>>>> Subject: Re: [ARSCLIST] Sticky shed - clogged heads?
>> >>>>>
>> >>>>> Dragon is the gold standard, the Rolls Ryce of cassette decks. Wish
>> >>>>> the
>> >>>>> project I have could make it affordable! :-)
>> >>>>>
>> >>>>> Maybe I don't want to know what you had to pay for it. ePay shows
>> >>>>> $1200
>> >>>>> -
>> >>>>> 3200 today.
>> >>>>>
>> >>>>> I got my lesser Naks for around $400 each. one needed service, the
>> >>>>> other
>> >>>>> was
>> >>>>> perfect.
>> >>>>> <L>
>> >>>>> Lou Judson
>> >>>>> Intuitive Audio
>> >>>>> 415-883-2689
>> >>>>>
>> >>>>> On Mar 31, 2018, at 9:35 AM, John Haley <[log in to unmask]>
>> >>>>> wrote:
>> >>>>>
>> >>>>>> I recently bought a Nak Dragon, which automatically sets the
>> >>>>>> azimuth
>> >>>>>> and keeps monitoring and resetting it as the cassette plays. And
>> >>>>>> I
>> >>>>>> recently dubbed a cassette in which the felt pad was missing. It
>> >>>> played
>> >>>>> fine. The
>> >>>>>> sound quality is astonishingly good. It really beats my Tascam
>> >>>>>> unit.
>> >>>>>> Best,
>> >>>>>> John Haley
>> >
>>
>>
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