Anyone have any experience with one of these amps? I pulled it from an old console phonograph. Cabinets were in poor shape so I collected the amp and all 4 speakers. Turntable is beyond it's usable days. I was hoping someone could give me some insight as to whether to rebuild with some mods or should I maybe go with a start from scratch salvaging pt and ot's. Tube line up is 12a x7, 12au7, 2 times el84 and a 5y3gt. Any thoughts on this?
Zenith 5b27
- Thread starter dave125
- Start date
FlaCharlie
Super Member
I pulled one from a somewhat different console a while back but I haven't done anything with it yet. Definitely worth restoring, though.
Some of the Zenith console speakers are very well regarded. What numbers are on the back of yours?
I have a more basic SE Zenith 6V6 mono amp that I've used for years with a Sherwood mono tuner and it sounds really nice.
Here's the Sams schematic for the SE 6BQ5 / EL84 amp.
Some of the Zenith console speakers are very well regarded. What numbers are on the back of yours?
I have a more basic SE Zenith 6V6 mono amp that I've used for years with a Sherwood mono tuner and it sounds really nice.
Here's the Sams schematic for the SE 6BQ5 / EL84 amp.
The speakers are woofers 49cz855 and tweeters 49d846. Looks like it should be a pretty nice amp. Should any changes be made for use as a line amp instead of for ceramic pickup? In other words II'm guessing I would not want to keep the phono stage intack.
It does look as though it has great potential.
Thank you for the Sams file Charley
It does look as though it has great potential.
Thank you for the Sams file Charley
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Ceramic phono doesn't need EQ - it's essentially line level. The bass/treble boost from the loudness control may be too much, depending on source level. Will have little effect near full volume. If it's excessive, clip off the components at the taps on the loudness control, which will then be straight volume without the low-level boosting of bass and treble.
FlaCharlie
Super Member
I'm using some similar 12" Zeniths (woofers only), in an open baffle. They're just mounted to their original baffle now but I eventually want to mount them in a more permanent setup. I'm running them essentially full range using a triamp setup with active crossover and they are outstanding. Augmenting the full range with woofers on the bottom and some tweeters on top but they work pretty well on their own.
I plan on keeping the baffles that the speakers were mounted on and build cabs for them at some point. The tweeters have 3mf 30 volt non polarized caps on them which I need to round up. Dont remember seeing anything like that at AES so need to check that out. Hopefully the woofers will be as nice as the 12" 852s are considered to be. Between this amp, the rca console and a 4s preamp Im building I'll be busy for awhile. I appreciate all the info.
FlaCharlie
Super Member
Your speakers should sound really good. I believe they are essentially a 10" version of the 852s, which is what I'm using. I have some other Zenith 12s and a single 10" with the same 49cz prefix that sound just as nice. I'm not sure how they'd sound in a cabinet. Being mounted in a console with a back panel that's full of holes for ventilation or even completely open is closer to an open baffle so they may not be designed for, or sound as good in, a cabinet. Best bet might be a cabinet with no back.
I would think that Digi-Key would have non-polar caps but the modern equivalent would probably be 3.3uf, which should be fine.
I will for sure leave the backs open on the new enclosures. The original cabinets were actually two seperate cabs that are about 30 x 30 x 15 deep and in rough shape. I planned on cutting the baffles down to about 15" wide due to lack of room for bigger cabs. I'll check on the caps as per your suggestion.
Well it's been awhile since I have looked at this amp. What I would like to do is use the power transformer and output transformers and build them up as a RH84 version one. Kegger stated in one of his posts that the rh84 required 80 ma. I would like to add a tone stack from Max Robinson (fun with tubes).
My question are the photofacts for the 5B27 show the power transformer as 660vct, 75ma, 6.3 volts@2.1 amp and 5volt@2 amp. The original 5b27 runs 5y3, 2x el84, 12ax7 and 12au7. I would be keeping the 5y3 and el84s, 12ax7 and using a 12at7 instead of the 12au7. So, I Guess what I'm saying is if this PT ran the same tube lineup originally except for swapping 12au7 for 12at7 shouldn't it be ok current wise? Also, is it possibly rated too low on the photofacts sheet? One last thought for now is in would use a choke in place of resister between first and second cap on power supply and drop first cap from 40uf to 10uf. I appreciate any thought on this.
My question are the photofacts for the 5B27 show the power transformer as 660vct, 75ma, 6.3 volts@2.1 amp and 5volt@2 amp. The original 5b27 runs 5y3, 2x el84, 12ax7 and 12au7. I would be keeping the 5y3 and el84s, 12ax7 and using a 12at7 instead of the 12au7. So, I Guess what I'm saying is if this PT ran the same tube lineup originally except for swapping 12au7 for 12at7 shouldn't it be ok current wise? Also, is it possibly rated too low on the photofacts sheet? One last thought for now is in would use a choke in place of resister between first and second cap on power supply and drop first cap from 40uf to 10uf. I appreciate any thought on this.
