$(document).ready(function(){
  $('#forma').on('submit', function(e){
    e.preventDefault();
    var $that = $(this),
    formData = new FormData($that.get(0)); // создаем новый экземпляр объекта и передаем ему нашу форму (*)
    $.ajax({
      url: $that.attr('action'),
      type: $that.attr('method'),
      contentType: false, // важно - убираем форматирование данных по умолчанию
      processData: false, // важно - убираем преобразование строк по умолчанию
      data: formData,
      dataType: 'json',
      success: function(res){
        if(res){
        $('.answer_forma').html('');
            if(res['error'] != ''){
                $('.answer_forma').append(res['error'])
            }else{
                $('.answer_forma').append(res['success'])
            }
            console.log(res)
        }
      }
    });
  });
});

$(document).ready(function(){
    tinymce.init({
    selector: '.redactor_mini',
    language: 'ru',
    height: 300,
    theme: 'modern',
    menubar: false,
    plugins: [
        'advlist autolink lists link image charmap print preview anchor',
        'searchreplace visualblocks fullscreen',
        'insertdatetime contextmenu'
      ],
          toolbar1: 'formatselect bold italic forecolor backcolor link alignleft aligncenter alignright alignjustify numlist bullist removeformat ',
    image_advtab: true,
    powerpaste_allow_local_images: true,
    paste_retain_style_properties: "font-family",
    content_css: [
      '/admin/templates/css/tinymce.css'
    ]
   });
});

<form action="" method="POST" id="forma" enctype="multipart/form-data">
    <div class="answer_forma"></div>
    <div class="panel_body">
        <div class="input_list">
            <label>Название</label>
            <input type="text" name="save_arr[name]" value="" />
        </div>
        <div class="input_list">
            <label>Текст</label>
            <textarea class="input_edit text_left redactor_mini" name="save_arr[text]"></textarea>
        </div>
        <button type="submit" name="save" class="button_normal">Сохранить</button>
    </div>
    <div class="clear"></div>
</form>