Amplifier to power JBL Voice of Theater Speakers

Do you have JBL or Altec both were made with horn drivers but the "Voice Of The Theater" were made by Altec. It doesn't matter all that much with regard to amplification as both were very highly efficient.
These speakers do best IMO with tube amplification. That said I would stay with your pre but not recommend ARC amps. I would choose a more lush amp to work in synergy with the speakers. There are numerous possibilities with these as they don't require a lot of power.
If you go SS find amps that are "musical" or warmish. One of the SS possibilities is an older McIntosh amp, which I have used with some success.
There is one thing that I have not done with my own vintage gear (JBL and Klipsch) which is to ensure that the (Alnico) speaker magnets are working at full capacity. I would have to ask others how that is done.

The pictures look a lot like Altec Voice Of The Theatre. JBL speakers made early on (I own two pairs) offered cabinet styles and speaker crossover package to fill the cabinets with. So my C36s have the 030 If I recall correctly, using the 15 inch 16 ohm D-130 extended range woofer/mids speaker and the 075 titanium/aluminum Bullet horns also 16 ohm, and the N2400 crossovers.
Your speakers are from a later period, but make use of the JBL Lansing Heritage pages. In particular look at the product brochures in the "libray" section of the website.