Magnavox 185 options

[fiddlerman]

Hi everyone,

I'm about to acquire a console-pulled Magnavox 185. It worked last time it was hooked up, which was several years ago. The buyer is recommending that I replace all the capacitors, which I'm planning on doing.

But I'm at a crossroads. The 185 was phono-only amp attached to a turntable with a ceramic cartridge. Is it safe to assume the two RCA ins are above line-level but not up to the level that would accomodate a magnetic cartridge?

If so, is it absolutely necessary to remove this phono pre circuit? Doesn't keeping it in just make the amp "louder" than line level?

Silly newbie question, I confess that my knowledge of electronics is next to nothing.

I've read a lot about people removing the phono circuit to convert the 185 into a 175. What I'm asking is whether this is actually necessary. Is there a good reason for this? Would keeping the phono circuit intact raise the noise floor of the amp?

Has anyone here hooked up a line-level device, such as a preamp, through an 185 phono circuit as it stands?

I'm planning to use an external pre-amp selector to run this amp.

Thanks in advance for your answers.

 

[gadget73]

The 185 has an extra gain stage that the 175 does not have. Its probably too much gain to be really useful without a fair bit of work though. Me I might set it up as a cathode follower so you can stick a volume control and a source selector in there without the frequency response changing with volume position. if you do need more gain, maybe change the 7025/12ax7 to a much lower gain tube like a 12au7 or 6cg7.

 

[Lavane]

Some have just changed the 185 into a 175. It isn't much work, but I like Gadget's idea better. If you do a search here on AK for the Magnavox 185 and 175 you will find plenty of threads to read through. I had a couple 175's.
The 185's and 175's do sound pretty good once sorted out.

 

[grindfix]

Me I might set it up as a cathode follower so you can stick a volume control and a source selector in there without the frequency response changing with volume position.

^^^ this.
I followed this recommendation and it turned out well.

Magnavox Amp 185 question

I have this console pull that came out of record player unit without tuner. I found correct stock schematic for reference. I'd like to recap this amp and modify it to make integrated amp with phono. I saw post of that done but output tubes and transformers were replaced, so that's not what I...

audiokarma.org