keithpgdrb
Super Member
Man, I am seriously amazed at how quickly you've gotten all this done!! Kudos.
New to Tubes...800c score...help restore.
- Thread starter marloubow
- Start date
marloubow
Best Day Ever
Follow up...
As you may have noticed I didn't post any new numbers last night. It was very late and I didn't trust my abilities should something go wrong.
So after checking and rechecking all the connections and components. Making sure none of my pots were pegged one direction or another. I flipped the switch.
Here is my reward...
123.5V AC
Neg bias Supply at R119...-18.01
V10
Pin 3 426
Pin 4 383
Pin 5 30.80
Pin 6 -16.86
V11
Pin 3 426
Pin 4 383
Pin 5 31.17
Pin 6 -17.14
V13
Pin 3 426
Pin 4 383
Pin 5 31.09
Pin 6 -17.18
V14
Pin 3 426
Pin 4 383
Pin 5 31.27
Pin 6 -17.53
There is one downside. Because there was about a 5 mA difference between V10 and V14 before the Individual Bias Adjustment Mod (man...I am tired of typing that...IBAM), it has taken the full range of both of those pots to bring the numbers as close as they are. So naturally the pots on V11 & V13 have room to spare. I should probably spread the numbers on V10 & V11 to get (-) bias down into the -17 range on V10. But it was fun to see how close I could get the current draw (mA) to match.
Overall I'm pleased. Like I said, the low end has been firming up over the past couple of days. I had been running the 800c thru my AR3a's and was liking it. But about 30 min ago I switched to my JBL 4410a's and I really like what I'm hearing. The expansion of the soundstage was quite noticable, real depth and seperation.
We're Rockin' now!
Martin likes it! :thmbsp:
Martin
P.s. Thanks Fisher...I needed that.
Thanks Bruce, very kind words. "If' people are using it as reference, you guys need to be checking my procedures and applications. I'm a newb!
And there are still some nice guys here in Enid America.
Keith...like I said...it has consumed me. The most common heard phrase around here is..."where else do you think dad is...basement"
Sad note...tuner section still dead...I need a resurection!
As you may have noticed I didn't post any new numbers last night. It was very late and I didn't trust my abilities should something go wrong.
So after checking and rechecking all the connections and components. Making sure none of my pots were pegged one direction or another. I flipped the switch.
Here is my reward...
123.5V AC
Neg bias Supply at R119...-18.01
V10
Pin 3 426
Pin 4 383
Pin 5 30.80
Pin 6 -16.86
V11
Pin 3 426
Pin 4 383
Pin 5 31.17
Pin 6 -17.14
V13
Pin 3 426
Pin 4 383
Pin 5 31.09
Pin 6 -17.18
V14
Pin 3 426
Pin 4 383
Pin 5 31.27
Pin 6 -17.53
There is one downside. Because there was about a 5 mA difference between V10 and V14 before the Individual Bias Adjustment Mod (man...I am tired of typing that...IBAM), it has taken the full range of both of those pots to bring the numbers as close as they are. So naturally the pots on V11 & V13 have room to spare. I should probably spread the numbers on V10 & V11 to get (-) bias down into the -17 range on V10. But it was fun to see how close I could get the current draw (mA) to match.
Overall I'm pleased. Like I said, the low end has been firming up over the past couple of days. I had been running the 800c thru my AR3a's and was liking it. But about 30 min ago I switched to my JBL 4410a's and I really like what I'm hearing. The expansion of the soundstage was quite noticable, real depth and seperation.
We're Rockin' now!
Martin likes it! :thmbsp:
Martin
P.s. Thanks Fisher...I needed that.
Thanks Bruce, very kind words. "If' people are using it as reference, you guys need to be checking my procedures and applications. I'm a newb!
And there are still some nice guys here in Enid America.
Keith...like I said...it has consumed me. The most common heard phrase around here is..."where else do you think dad is...basement"
Sad note...tuner section still dead...I need a resurection!
Last edited:
marloubow
Best Day Ever
The final word…
On Monday the multi section caps arrived from hayseed. Man…they do look nice!
That same evening I installed them. It was really very easy to remove the old and install the new. A perfect fit.
Again, I drew out the circuitry, just in case. And of course checked and rechecked before applying power.
The can lugs with solder, I just used a pair of hefty needle nose pliers and gently twisted back and forth till they snapped. A bit barbaric, but what the heck, I had no visions of using them again.
I would add a picture here, but it would look just like a before shot. Really not much difference at all, aside from new resistors, it looks about the same, at least from the underside.
Now for the goods…
Everything about the 800c took a leap forward with addition of the new cans. They easily took things to the next level. I mean…WOW!
Words can’t do justice to how good this 800c sounds. And I thought it sounded good from the git go. It just keeps getting better and better.
Thanks guys for encouraging me to go all the way with this restore.
And the numbers…
V10
Pin 3 432
Pin 4 399
Pin 5 32.10
Pin 6 -17.42
V11
Pin 3 432
Pin 4 399
Pin 5 32.44
Pin 6 -17.66
V10
Pin 3 432
Pin 4 399
Pin 5 32.20
Pin 6 -17.73
V10
Pin 3 432
Pin 4 399
Pin 5 32.30
Pin 6 -18.07
I really couldn’t be happier with the outcome.
Really guys, thanks, for all the help and not losing patience with me.
martin
P.s. When I have everything completely put together, I’ll post one last set of pictures.
On Monday the multi section caps arrived from hayseed. Man…they do look nice!
That same evening I installed them. It was really very easy to remove the old and install the new. A perfect fit.
Again, I drew out the circuitry, just in case. And of course checked and rechecked before applying power.
The can lugs with solder, I just used a pair of hefty needle nose pliers and gently twisted back and forth till they snapped. A bit barbaric, but what the heck, I had no visions of using them again.
I would add a picture here, but it would look just like a before shot. Really not much difference at all, aside from new resistors, it looks about the same, at least from the underside.
Now for the goods…
Everything about the 800c took a leap forward with addition of the new cans. They easily took things to the next level. I mean…WOW!
Words can’t do justice to how good this 800c sounds. And I thought it sounded good from the git go. It just keeps getting better and better.
Thanks guys for encouraging me to go all the way with this restore.
And the numbers…
V10
Pin 3 432
Pin 4 399
Pin 5 32.10
Pin 6 -17.42
V11
Pin 3 432
Pin 4 399
Pin 5 32.44
Pin 6 -17.66
V10
Pin 3 432
Pin 4 399
Pin 5 32.20
Pin 6 -17.73
V10
Pin 3 432
Pin 4 399
Pin 5 32.30
Pin 6 -18.07
I really couldn’t be happier with the outcome.
Really guys, thanks, for all the help and not losing patience with me.
martin
P.s. When I have everything completely put together, I’ll post one last set of pictures.
bhamham
Super Member
Really good work, Martin!
Those numbers look very healthy and you'll probably have decades of enjoyment from your 800C.
I'll get on my soapbox for a minute and no offence to you Martin or anybody... I see so many get Fisher and other tube amps and they buy the Metalbone kit to do just the coupling caps and a few resistors thinking it's going to sing like new. Instead of 'It's the Economy, stupid' there should be a saying in tube gear 'It's the Power Supply, stupid'. That should be the first thing anyone rebuilds. I don't mean to sound like an expert b/c I'm learning just like most here, however, after a several rebuilds, I do the PS first after that everything else seems easy. Sorry for the rant but I see it so much.
Those numbers look very healthy and you'll probably have decades of enjoyment from your 800C.
I'll get on my soapbox for a minute and no offence to you Martin or anybody... I see so many get Fisher and other tube amps and they buy the Metalbone kit to do just the coupling caps and a few resistors thinking it's going to sing like new. Instead of 'It's the Economy, stupid' there should be a saying in tube gear 'It's the Power Supply, stupid'. That should be the first thing anyone rebuilds. I don't mean to sound like an expert b/c I'm learning just like most here, however, after a several rebuilds, I do the PS first after that everything else seems easy. Sorry for the rant but I see it so much.
I was just coming here to pretty much say the exact same thing! I used to be in the camp that if voltages were good and there was no hum then leave the cans be, which might of just been an excuse for not knowing what the heck I was doing at the time but once I started rebuilding the entire power supplies on tube gear the difference is immediately apparent! Fisher gear with original cans tends to have flabby bass and an overly warm sound. I notice immediately when the PS is rebuilt how much better the low end is and seems to have a much more crisp, "accurate" sound? I'm not the best at putting the sound into words but that's the best way I can describe it.
Truck99's 500B I rebuilt sounded better when I recapped it but it entered greatness when the PS was brand new. I listened to it both ways because I was waiting for the cans to come. His original PS cans were seemingly "fine".
Kory
PS: The metalbone kit has some nice quality parts in it and will make your Fisher safe for the time being, BUT if you're going to go to all the effort to do that much, you ought to do it right. 2/4 of the last Fisher receivers I've recapped have had power supply issues...These are 50 years old now, I think things that weren't a common problem 10 years ago are starting to rear their ugly head.
marloubow
Best Day Ever
Update...
My 800c has been in the shop for the last few days to see if the dead tuner section could be repaired.
It is and I thought you all should know why.
I could have figured it out myself if I had taken a closer look at the work I had done on the can cap replacements. On post #131 I listed the resistors associated with the multi section capacitors. I had listed R129 & R121 as 470k and should have been just 470 ohms. So that high of a resistance brought my voltages down enough for the tuner section not to work.
Also I had R120 and R117 swapped.
I have since edited that post to show correct values and locations. I hope this hasn't caused anyone else problems with their units. If so, I apologize.
These problems stemmed from working from notes and not schematics. Always check against schematics...always.
Lesson learned...I hope.
martin
P/s will copy this to the "Tuner Section Dead on 800c" thread.
My 800c has been in the shop for the last few days to see if the dead tuner section could be repaired.
It is and I thought you all should know why.
I could have figured it out myself if I had taken a closer look at the work I had done on the can cap replacements. On post #131 I listed the resistors associated with the multi section capacitors. I had listed R129 & R121 as 470k and should have been just 470 ohms. So that high of a resistance brought my voltages down enough for the tuner section not to work.
Also I had R120 and R117 swapped.
I have since edited that post to show correct values and locations. I hope this hasn't caused anyone else problems with their units. If so, I apologize.
These problems stemmed from working from notes and not schematics. Always check against schematics...always.
Lesson learned...I hope.
martin
P/s will copy this to the "Tuner Section Dead on 800c" thread.
Last edited:
keithpgdrb
Super Member
Hey Martin,
congrats on finishing up the amp. seriously, great Job. I was wondering if you could tell me a bit about how you replaced C98, the single 200uf cap. did you just desolder the connections from the old cap and keep it in place? I see a piece of your new cap strapped to the side in a couple of your pictures. I was a little worried about the whole floating negitive, not touching the chassis thing. Would you mind snapping a full picture of how you made those new connections? sorry if its already prettied up and in your system.
congrats on finishing up the amp. seriously, great Job. I was wondering if you could tell me a bit about how you replaced C98, the single 200uf cap. did you just desolder the connections from the old cap and keep it in place? I see a piece of your new cap strapped to the side in a couple of your pictures. I was a little worried about the whole floating negitive, not touching the chassis thing. Would you mind snapping a full picture of how you made those new connections? sorry if its already prettied up and in your system.
marloubow
Best Day Ever
Keith...
My 800c is in fact in use now in its new cabinet. :thmbsp:
I do plan to remove it from use soon to take some finished photos. I will double check to see what I did. I may have cinched it with only the wires as insulation. When I take it apart next time, I will put a layer or two of rubber between the cap and the wire/chassis.
Again...thanks for the heads up.
martin
P.s. Yes...I left the "can" in place and just made the new connections below. I can't believe I didn't document it better. Probably because it seemed fairly easy.
My 800c is in fact in use now in its new cabinet. :thmbsp:
I do plan to remove it from use soon to take some finished photos. I will double check to see what I did. I may have cinched it with only the wires as insulation. When I take it apart next time, I will put a layer or two of rubber between the cap and the wire/chassis.
Again...thanks for the heads up.
martin
P.s. Yes...I left the "can" in place and just made the new connections below. I can't believe I didn't document it better. Probably because it seemed fairly easy.
Last edited:
marloubow
Best Day Ever
Okay Keith...
Seemed like good as time as any to get some final pictures done, so here you go.
I was glad to see that I had insulated the cap from the chasis with some rubber and kept the wires at easy access...how could I have doubted myself?
Memory is a curious thing at best...I think? :scratch2:
martin
Seemed like good as time as any to get some final pictures done, so here you go.
I was glad to see that I had insulated the cap from the chasis with some rubber and kept the wires at easy access...how could I have doubted myself?
Memory is a curious thing at best...I think? :scratch2:
martin
Great Job Martin. Soon to do my 800C (got from Buglegirl) in the next month or so. Already decided to replace all 3 can's with Hayseed Repro's. Right now it's got a hodge-podge of Spragues and Nichicon's and F-42 Teflon coupling caps in .047. Gonna take it up to .1 and 220K on the grid resistors to run EH 7591's.
Bias diodes in the pic above. 1n540??? Did you consider maybe UF5404 or UF 5406. Slightly faster and less noise.
One note on the IBAM! (Don't you just love abbreviations!). You really don't need R-119 in there now as the other 4(on the board) are now doing that job. Very nice job wiring it. I'd lock it down with a touch of Nail polish tho, just in case it gets bumped and thrown out of whack.
Have you got a schematic from Drew on the IBAM board? Or is it the same as the 400. If so I can use that one.
Larry
Bias diodes in the pic above. 1n540??? Did you consider maybe UF5404 or UF 5406. Slightly faster and less noise.
One note on the IBAM! (Don't you just love abbreviations!). You really don't need R-119 in there now as the other 4(on the board) are now doing that job. Very nice job wiring it. I'd lock it down with a touch of Nail polish tho, just in case it gets bumped and thrown out of whack.
Have you got a schematic from Drew on the IBAM board? Or is it the same as the 400. If so I can use that one.
Larry
marloubow
Best Day Ever
Larry...
Thanks for the nod! :thmbsp:
I used the diodes that were supplied in the metalbones kit. Being my first go round, I didn't seek out other options. But your suggestions give me something to ponder. What does "Slightly faster and less noise" mean to us less "learned".
Now that I've completed the unit to satisfaction, I can start thinking about other mods if I choose to play around later.
I'm tossing around the idea of replacing the pot at R119, but not commited myself to anything. Especially if I still plan to make some other changes later.
Yes, I used the 400c schematic. I believe all the specs are the same. I didn't change anything.
Thanks again
martin
Thanks for the nod! :thmbsp:
I used the diodes that were supplied in the metalbones kit. Being my first go round, I didn't seek out other options. But your suggestions give me something to ponder. What does "Slightly faster and less noise" mean to us less "learned".
Now that I've completed the unit to satisfaction, I can start thinking about other mods if I choose to play around later.
I'm tossing around the idea of replacing the pot at R119, but not commited myself to anything. Especially if I still plan to make some other changes later.
Yes, I used the 400c schematic. I believe all the specs are the same. I didn't change anything.
Thanks again
martin
Only if they're NOT of my wife! Why look at pics when I've got the real thing.
:tresbon:tube-a-lou
Addicted Member
Hi,
How do those Sonic caps sound in that Fisher??
Tube
How do those Sonic caps sound in that Fisher??
Tube
marloubow
Best Day Ever
Tube...
I have nothing to compare them to. But I do like the way 800c sounds at the moment.
But I promise if you send me some russian pio's, I'll put them in and get back to you with a full report. :thmbsp:
Gee whiz guys...my unit is less than a week finished and you have me thinking mods. You guys are brutal!
I've been told that junkies get addicted to the ritual and needle prick as much as the dope...hmmmm? :scratch2:
martin
I have nothing to compare them to. But I do like the way 800c sounds at the moment.
But I promise if you send me some russian pio's, I'll put them in and get back to you with a full report. :thmbsp:
Gee whiz guys...my unit is less than a week finished and you have me thinking mods. You guys are brutal!
I've been told that junkies get addicted to the ritual and needle prick as much as the dope...hmmmm? :scratch2:
martin
keithpgdrb
Super Member
Thanks for throwing up those pics martin. very helpful. what kind of rubber thing did you use to isolate from the chassis?
tube-a-lou
Addicted Member
Tube...
I have nothing to compare them to. But I do like the way 800c sounds at the moment.
But I promise if you send me some russian pio's, I'll put them in and get back to you with a full report. :thmbsp:
Gee whiz guys...my unit is less than a week finished and you have me thinking mods. You guys are brutal!
I've been told that junkies get addicted to the ritual and needle prick as much as the dope...hmmmm? :scratch2:
martin
Hi,
That's because we love this stuff!!
Tube
