When the logo is put into the PDF it looks perfectly fine at 100% zoom 1:1 ratio.
Put into the pdf and viewed with what application?
is there anyway I can blow it up without having to redo it from scratch?
Did you create it with Type and Shape Layers or pixel Layers?
In the former case saving in a format that can support vector data (pdf, eps) may be an option.
Not yet mentioned is that viewing at magnifications other than 100% is subject to optimizations in whatever application you're using to view it.
Trying to judge how something looks in Photoshop at 75% zoom, you will find that there are degradations. Further, the amount of these may differ (e.g., have more or fewer jaggies) if you have Graphics Processor acceleration deselected vs. selected. There's even another option (Cache Levels) which can affect preview quality.
So, now knowing that what you're seeing in Photoshop at zoom levels other than 100% is an approximation, optimized for quick screen display and set up so that you can get an overview of your image rather than examine details, do you care any longer whether the preview doesn't look perfect at 75% zoom?
Thanks everyone. Perhaps because its vector data, but transorming the old logo rectified this issue. I simply copied the old logo into a new 1900x1200 canvas, transformed the old image to fill as much of the new canvas as possible, then cropped off the rest.
Transform scaled it up perfectly, maintaining the originals quality.