The time the Tallis and Tefillin are put on and taken off

All old books bring that the time to put on the Tallis and the Tefillin is before Psukei Dezimroh. The Machzor vitri brings that the French minhag was to put on the Tallis and Tefillin just before Yishtabach! both in the winter (when sunrise was late) and the summer (when there was no problem to put the Tallis and Tefillin on earlier).

The reasons for not putting on the Tallis and Tefillin before Davening but only just before Psukei Dezimroh are two:
To be able to say the Brochos out loud so the Tzibbur can say Omen (this is done by the Rov and the Chazzan).
The Tefillin need a clean body and clean thoughts, and since we cannot keep the Tefillin properly, we do not put the Tefillin on all day and even not in all the Tefillos, but only in Shacharis. For the same reason the Tefillin were not put on until the last place you could say the berocho on the Tefillin without it being considered Hefsek, which was generally considered to be before Boruch She'omar, and in France they held the last stop was even later - before Yishtabach. The Tallis was put on the same time the Tefillin were.

Michael FRBSH

I was sent this quote from Rav Shimon Schwab ZT"L, in the sefer "Rav Schwab On Prayer", which is what you must be referring to:

"According to our minhog, which is prevalent in most of Ashkenaz, the tallis and tefillin are put on before Boruch SheOmar. However, in the Tur and Shulchon Oruch, the halochos of tzitzis and tefillin precede Birchos HaShachar. It is for this reason that, in most of the Jewish world, the tallis and tefillin are put on before the beginning of the tefilloh.

The origin of our minhog seems to be very simple. The prevalent custom throughout most of Ashkenaz was to begin Shacharis very early. Many times during the year, this was too early for putting on tallis and tefillin.... By the time one reached Boruch SheOmar, the requisite times for tallis and tefillin had arrived.

The proof for this reason is that, on Shabbos and Yom Tov, when it is a mitzvoh to begin the tefilloh somewhat later (Ramoh, Orach Chayim 281), it is indeed, our minhog to put on the tallis at the beginning of Shacharis.

But on Rosh HaShonoh and Yom Kippur, when it is a mitzvoh to start the tefilloh early (see Selichos Erev Rosh Hashonoh 52), we wait to put on the tallis until just before Boruch SheOmar, for the same reason that we do on weekdays."

Although one of the reasons to put the Tallis and Tefillin on before Boruch She'omar is because it was sometimes the earliest time that they could be put on Halachicly (and this reason was brought in the Mateh Moshe), the Tallis and Tefillin were put on both in the summer and in the winter before boruch she'omar, even though in the summer there is no problem with the time of the Tallis.
In addition to this, we put the Tallis on before Boruch She'omar also on Shabbos, so according to our minhag this couldn't be the explanation.
Rav Schwab ZT"L writes that it was done differently on Shabbos, it's very interesting to know from where the two different minhogim originate.

Michael

Minhag Ashkenaz is to put on the Tallis and Tefillin in Shul just before Boruch She'omar. Minhag Ha'Ari is to put on the Tallis and Tefillin at home before going to Shul, and in this way when he goes through the door he has three Ousos - Tzitzis, Tefillin and Mezuzoh.
According to Minhag Ashkenaz Birkos Hashachar are said out loud, and so are the Brochos of Tallis and Tefillin by the Shatz and the Rov, and in this way one can answer Omein, which is a big Mitzvoh, and there also is an Inyon that one says 91 Omens every day.
If one wants to follow Minhag Ha'Ari and put in Tallis and Tefillin at home, it is still important that he comes to Shul at the time of Birkos Hashachar (even if he said them at home), to answer these Omeins.

Michael FRBSH

There were different Minhogim, but the Maharil (עמוד שצ"ו מכון ירושלים) took off the Tallis and Tefillin after Oleinu, and Rav Hirsch writes that one should take it off after the Oleinu Kaddish (Kaddish after Oleinu, as was the Minhag in Hamburg).

Michael FRBSH