Memorex surprise, Radio Trash crap

Continuing my goofing off, I found that decreasing bias a full 4 dB
unlocked to potential of the Memorex oxide pretty much. Nice highs
(better than earlier Scotch "low noise") and a "hot" tape...once you
back the bias off, it's give you back about 3 dB more than does
Dynarange, making it a pretty really good oxide for those "car tapes"
everyone does with 8 track. The problem was the bias was just more
than this oxide could handle. Now we know exactly why so many later
cassette manufacturers had front panel adjustable bias on their
machines...oxides DO vary a great deal.

Again for laughs, with bias down this low, I went back to an Ampex
84...ick! TOO much top end (to be expected) and NASTY 3rd harmonic
distortion. So, I kicked in the handy dandy "special" switch on the
front panel of the 8075, and viola! Ampex sounded good again. It
looks like that switch kicks up the bias current about 5 dB, and that
just might be the ticket, since Scotch "Classic" carts are rare.
However, now Dynarange sits in the mid point of the two...too low at
"normal" to be listenable, too high at "special" to get good top end.
A kind list member has offered me a couple of Classics so I can do
some testing on those, but I need to figure out what to trade for
them. I'll get to you off list on that!

There were some comments from the lamebrain about how the Wollensak's
drive system sucks so badly, but to date, I've had zero problems with
wow and flutter...once I run an NOS cart a few times to "break it in,"
common practice with cassettes for years. I've also been
experimenting with PTFE to use on all guides that contact the backing
on a couple of carts, just to see if it aids and abets the dried out
old graphite based lubricant. So far, results are really good.
Formerly balky carts, especially the crappy BASF/Radio Trash
"Stupid-tapes", come out with about the same drag as everything else,
as do the problematic GRT "K wrap" carts. Only one place for Radio
Trash cartridges...the trash! Although made by BASF, they seemed to
have some sort of different cheeseball backing AND a different oxide,
and were measurably worse than the OEM BASF examples. The blue
"Stupid-tape" was just awful...kicking up the bais got rid of some of
the nasty distortion, but then the top end just sunk like a rock, and
the oxide seems to have NO headroom. I just decided not to
investigate them seriously and will probably sleazeBay my sealed
stock. I know one thing about Radio Trash tape on open reel...DON'T
get it near moisture, or the oxide just comes peeling off! Some
acetate backed Scotch used to do that, too, back in the old days.

Anyone have any better experience with Radio Trash "Stupid Tape?"

dB

You just highly insulted the Texas Pad & Foil gang, they love Radio
Shack stuff...

bias adjustment- if not stock specs, just turn it all the way down to
get max high end. Why go in these little increments- that's silly.

If you don't need the bias to record, shut the darn thing off and be
done with it, why keep pussy footing around with the adjustment.
Unless, of course, you have no life other than to move it 1/32" at a
time, measure it with your outdated test equipment- then make these
posts here trying to gain respect from the techs that are lurking.

That bias adjustment deal was documented and posted by J. Nechanicky
here, at least 2-3 years ago.

another reason why Akai decks are superior, they have a SEPARATE ERASE
HEAD, enabling the record/play head to offer exceptional performance,
here's a 2-year old post.


From: Joe Nechanicky
Subject: akai
View: Complete Thread (21 articles)
Original Format
Newsgroups: alt.collecting.8-track-tapes
Date: 2002-08-26


The combo heads E/R/P have separate gaps in the head for the erase, (
and
most use a common ground) the erase current in these recorders is
also the
bias current for the record head, the record gap gets its bias from
being in
close proximity to the erase head portion of the erase current field.
You
can get better top end out of a combo head arrangement if you decrease
the
bias, however the erase ratio goes down when top end goes up. On the
AKAIs,
( CR83 not included ) the tape guide and the erase head body are the
tape
sensing contacts. The erase head is fixed, non adjustable, it is the
reference point for aligning the R/P head. The record play head which
is
mounted on the head platform, in turn also has individual Tilt, and
height
adjustments on it. The best way to realign the record play head on
an AKAI
is to disconnect the erase head, then connect an audio oscillator to
the
erase head leads. Without bias, the recording will be distorted and
weak,
however it will give you a signal to follow when adjusting the record
play
heads for height to make ball park adjustments. Another way to adjust
the
record play head is to get a second AKAI, and use its bias oscillator
to
power the erase head in the machine undergoing adjustment. Using a
separate
deck allows you to have the deck under test in the play mode for
checking
the alignment. Then, with the erase oscillator running, use a tape
which was
recorded at about 3-5 KHZ on a good known machine with good alignment,
put
the tape in the machine under test and adjust the R/P head so you hear
no
sound as the tape passes the R/P head. Go slow and be carefull, you
have
three screws to turn which sets the head height, and head tilt, both
side to
side and back to back, its tricky...Another method is to make a metal
jig
which will fit with precision under the record play head and sit on
top of
the chassis base pan. Use a known good AKAI recorder which is in
adjustment
when you make this tool. Use track one for making the tool it will be
easier
to make as the distance from the chassis pan and the head will be
greater.
This tool can also be useful to make sure the head is parallel with
the tape
path. When you change heads or have a new deck which is way out of
alignment, just use the jig to get the R/P head very close to where it
should be, then trim up with the adjustments on the head platform,
followed
up by an over all height adjustment of the head platform which also
has the
erase head mounted on it.Doing this wll insure that the erase head and
R/P
head are lined up. This is a time consuming process, so give your self
an
afternoon when you dont have to be some place at four, you'll need
plenty of
time, they do adjust out nicely once you know the process. Nobody
should be
in the house when you do this.

And here's yet another one- this post is nearly 4 years old. You are
posting some interesting stuff D-Bob, and unlike your harassing flame
posts, I do read some of your tech posts. Just wanted you to know,
this subject was covered here before.


From: Joe Nechanicky
Subject: Player Purchase Advice
View: Complete Thread (10 articles)
Original Format
Newsgroups: alt.collecting.8-track-tapes
Date: 2000-11-22

The one thing most 8 track owners do not realize, the adjustment of
the bias
oscillator current to the record head can make any player come to
life. The
808 Panasonic is no exception. This deck does not have an "on board"
trimmer
for adjusting bias, but the voltage to the bias oscillator can be
reduced a
bit to decrease bias current ( and increasing bias oscillator
frequency )
This modification will make the 808 give you the highs you want. This
holds
true with any 8 track recorder. Most 8 track decks have heavy bias
currents
because the R/P head must act as an erase head as well as record head.
The
bias is compromised for a good erase ratio and fair frequency
response.
Reducing the bias current decreases erase ratio, but dramatically
increases
the top end response. It may be necessary to bulk erase tapes if you
want
optimum high end response after rebiasing a recorder. A small price to
pay
for a good top end.

DeserTBoB wrote:




Anyone have any better experience with Radio Trash "Stupid Tape?"

dB

yes, they only seem to like the bias on a roberts 1725 - 8L3 recorder. it
seems to bring the best out of them radio shack carts. the roberts 1725 is
a combo reel to reel deck with a 8 track recorder/playback transport built
into the side of the deck. the electronics utilizes vacumm tubes for the
bias oscilator, head preamp & output stage, the record front-end is
transistor. it seems that this is the only deck i found so far that can
bring out the best results on them radio-shock tapes.
--
aint' nuthing like the real thing, baby

On Sat, 16 Oct 2004 15:56:17 -0400, the animal wrote:

yes, they only seem to like the bias on a roberts 1725 - 8L3 recorder. snip
it seems that this is the only deck i found so far that can
bring out the best results on them radio-shock tapes. snip

Gotta be a reason...the blue cart Supertape seems bias hungry, sort of
like the ferrichomes, but when you bump up the bias current, the highs
all go to crap, moreso than with any other oxide. I think I'll ebay
the sealed ones I got...maybe "Yogi" will buy 'em for $10/cart! LMAO

dB

No thanks, not interested in "sealed" blanks.

Read Joe N's posts- any 8-track high end goes to crap when the bias is
turned up. Your wasting a lot of time re-inventing the wheel, this
information has already been covered here.

ANYTHING with tubes will always sound better.

there are companies out there modifying CD and DVD players, adding
tube output stages today to improve the sound