Subwoofer connection for Fisher 500c

Hello folks!

I recently acquired a Velodyne ULD-18 sub for next to nothing. By outward appearances it looks to be in excellent shape. The driver looks and feels excellent, and the 400 watt servo controller is in fine shape too. According to the owners manuel a normal way to connect the sub to a system is connecting the servo controller/amp in between your amp and preamp with two sets of RCA cables. So my problem is that I have this vintage Fisher 500c receiver. It has a "to reverb" feature with four inputs, a pair of right & left "ins" and a pair of right and left "outs." I was hoping this would be the way to connect it properly. However, I've got nothing happening in the way of sound from my monitors or the sub in this configuration.
Any help would be appreciated! I can send photos too, if that helps.
What speaker are you using? I would use the Velodyne in parallel (without active crossover) unless you have small bookshelf speakers. If you run in parallel, then you can connect from your L/R RCA outs on your Receiver to your sub. Keep running your speakers from your receiver via the speakerwire.

If you have bookshelves, pls post.
Thanks for your response Lloyd.
My speakers are smaller monitors- Sound Dynamics RTS-3's, though the bass cutoff isn't too high-probably around 45 or 50 hz.
I must say I did figure out how to get the sub running with them, but there are two things that still bug me.
1. The crossover/servo/amp Velodyne unit is preset at 85 hz, and cannot be adjusted.
2. The volume control for the sub and the volume control for my receiver cannot be synchronized together, so I have to adjust each separately.
Don't know if I can remedy this or not?

Thank you for any other advice anyone can offer!
Hi Lincnabby,

1. Yes that is what some Velodynes do...most of them in fact. Driven by hometheater specs more than music.

2. The volume control should always be adjusted by your preamp automatically...particularly if you are using the crossover. the reason is that the signal presumably originates from your preamp...goes out to the subwoofer.

I presume this is how you are using your Fisher receiver?
You are correct that the crossover is preset with no adjustment.

Since the amp/controller only has RCA line level connections and the 500C has no preamp out, but does have a tape out, are you connecting this tape out to the amp/controller? If so, that would explain the independent volume controls. It may be a possibility to use a speaker level to line level adapter on the speaker outputs in parallel with the speakers to drive the amp/controller. I have done this with solid state amplifiers, but not tubes. I’m thinking it should be OK, since the impedance load of the adapter is very high. This would allow you to use only the 500C volume control. The amp/controller VC would then be used to match levels between sub and speakers.
Agree with Tls49...try speaker cables to sub and speaker cables back to your speakers...perhaps not as good as line-out but you dont seem to have that option with your receiver. at least this way, you control speaker and sub volume simultaneously from your receiver volume control.
Lloydelee21, appreciate your agreement, however, “speaker cables to sub and speaker cables back to your speakers” is not possible with the ULD-18. The only input to the amp/controller is line level RCA. The speaker level to line level adapter connects to speaker outputs of the 500C in parallel with speakers, and gives you a line level RCA connection for the amp/controller.
Yes...just looked up the old manual from Velodyne're right. I suppose the good news is they used to sell a passive accessory that allowed you to bypass the 85hz crossover and i guess change it. They may not offer it anymore, but just a thought.

wont help with volume control, but might with your blending of the speakers with sub.