• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Addind a beautiful 400 to my Fisher Collection

Installed the brand new GE NOS main tubes, and they lit up nicely showing no signs of getting too hot. But not a peep of sound through the speakers :sigh: I'm not sure if the 100 watt bulb in my DBT was enough to get things working properly, the tuning beacon did not move to show channel center like it did without the mains installed.
 

Attachments

  • 013.jpg
    013.jpg
    52 KB · Views: 54
  • 014.jpg
    014.jpg
    80.1 KB · Views: 198
Likely need a bigger lamp (200 watts) if you're still using the DBT to power it. Those new 7868s sure are purdy!

Dave
 
dcgillespie said:
Likely need a bigger lamp (200 watts) if you're still using the DBT to power it. Those new 7868s sure are purdy!

Dave
Click to expand...

Thanks for your advice Dave, I used a 200 watt and it did produce clear sound from both channels. It is very weak though, I needed to turn it to almost 1/2 volume to get what should be 1/8 volume running my Minimus 7speakers I use for testing. I then plugged directly into the wall, there was no change in the volume level though.
 
attachment.php


You're going to need a bigger lamp.
 

Attachments

  • bigger-boat.jpg
    bigger-boat.jpg
    39.3 KB · Views: 106
audiodon said:
attachment.php


You're going to need a bigger lamp.
Click to expand...

Thats crazy! :D :thmbsp:

I plugged the 400 directly in the wall, but the volume level is still very weak. Maybe a preamp tube is not up to standard, any idea which tube or tubes would effect volume level on FM and aux?

I will probably leave well enough alone, and just get it serviced by an expert, I don't want to risk hurting those new tubes.
 
The two line stage tubes are the two 12AX7 tubes closest to the dial glass.
The two phase inverter tubes are the two 12AX7 tubes in front of the output transformers. Possible candidates for the swaperoo.
 
audiodon said:
The two line stage tubes are the two 12AX7 tubes closest to the dial glass.
The two phase inverter tubes are the two 12AX7 tubes in front of the output transformers. Possible candidates for the swaperoo.
Click to expand...

Both are brand new TungSol's, I doubt they are the problem but I'll check.
 
Steve -- If the signal level supplied from your 400 to the 1800 during your initial tests were such that the volume control on the 1800 seemed to operate in the normal range of expectations, then V10 is off the hook, as you might remember that it was included in the signal chain at that point. The portion of the audio chain not checked with the 1800 tests includes V11 through V17 -- but with all new tubes, the possibility of a tube being the problem seems unlikely. However, of those tubes, V11 serves BOTH channels, while V12 through V17 are all dedicated to one channel or the other.

Other things to check if the sound is weak: check that the tape monitor switch is not dirty, nor that the speaker on/off switch is as well.

Another way to test things is to do the previous tests with the 1800 somewhat in reverse. That is, come out of the recording output jacks of the 1800 using it as the source this time, and go into TAPE MONITOR inputs on the 400 with your interconnects. Turn the Tape Monitor Sw on the 400 ON. Now, every thing is reversed, with the 400 acting to control volume, tone, and balance of the sound, with the 1800 being the source. If there are problems in the 400 from V11 going forward, it will show itself with this test, with the same weak sound you noted earlier when it was operating in a complete stand alone fashion.

I hope this helps!

Dave
 
dcgillespie said:
Steve -- If the signal level supplied from your 400 to the 1800 during your initial tests were such that the volume control on the 1800 seemed to operate in the normal range of expectations, then V10 is off the hook, as you might remember that it was included in the signal chain at that point. The portion of the audio chain not checked with the 1800 tests includes V11 through V17 -- but with all new tubes, the possibility of a tube being the problem seems unlikely. However, of those tubes, V11 serves BOTH channels, while V12 through V17 are all dedicated to one channel or the other.

Other things to check if the sound is weak: check that the tape monitor switch is not dirty, nor that the speaker on/off switch is as well.

Another way to test things is to do the previous tests with the 1800 somewhat in reverse. That is, come out of the recording output jacks of the 1800 using it as the source this time, and go into TAPE MONITOR inputs on the 400 with your interconnects. Turn the Tape Monitor Sw on the 400 ON. Now, every thing is reversed, with the 400 acting to control volume, tone, and balance of the sound, with the 1800 being the source. If there are problems in the 400 from V11 going forward, it will show itself with this test, with the same weak sound you noted earlier when it was operating in a complete stand alone fashion.

I hope this helps!

Dave
Click to expand...

As usual Dave, your a great help. I will try doing those things.
 
After a real good Deox job, the 400 is doing much better. :thmbsp: The volume doesn't change much until you get near 12 oclock, but everything looks and sounds like it is working good. Thought I'd show off the mains in action. :smoke:

attachment.php
 

Attachments

  • 016.jpg
    016.jpg
    14.5 KB · Views: 151
Ok, after figuring out which phono jacks to use with my turntable, the phono section on the 400 is working great too. The main power tubes seemed to be putting off too much heat, but now it's destined for a full tilt check up to make it good as new. I'm just glad it doesn't have any major issues to start with. I'll post more when it is finished and singing its new songs. :thmbsp:


attachment.php
 

Attachments

  • 007.jpg
    007.jpg
    17 KB · Views: 287
It doesn't appear that there's any color to the plates, so while they may be running hotter than they should, at least it doesn't look grossly excessive. Great pic!!

Dave
 
400 D. G. restored

I just returned home from my 3 week away trip to get my parents estate in order after the recent loss of my stepmother. It allowed me to take this nice 400 Fisher, and drop it in Dave's lap instead of shipping it. What a great pleasure to sit down and talk with AK's Fisher expert, my brother and I really enjoyed it. And on my return trip, I picked up my 400, and ST-70 all fixed up. This 400 is now over the top with unbelievable sound, can't wait to get more listening time with it. Thanks again Dave! :thmbsp:
 
I was lucky enough to find a beautiful Fisher wood cabinet for my restored 400, it now looks as good as it sounds. This unit will reside next to my other Fisher's, and it's become one of my favorites after Dave worked his magic on the restoration. I wanted to add this last parting shot after being put through its paces, and wrapped in its new skin. Unbelievable sounding piece of Fisher history ready to have its new life.:thmbsp:

attachment.php
 

Attachments

  • 20150825_202533.jpg
    20150825_202533.jpg
    66.9 KB · Views: 69
  • 20150825_202609.jpg
    20150825_202609.jpg
    66.1 KB · Views: 22
  • 20150825_202645.jpg
    20150825_202645.jpg
    67.5 KB · Views: 22
NICE!!!!

Run some Howards Restore a Finish (Walnut) on it , then oil it down and rub it out. When I got the one for my 800-c it took 5 coats of oil before it stopped soaking it up. Talk about dry. But it looks good. Re-Oil it yearly or whenever it starts looking dull or dry.
 
larryderouin said:
NICE!!!!

Run some Howards Restore a Finish (Walnut) on it , then oil it down and rub it out. When I got the one for my 800-c it took 5 coats of oil before it stopped soaking it up. Talk about dry. But it looks good. Re-Oil it yearly or whenever it starts looking dull or dry.
Click to expand...

Yeah Larry, part of my routine already, it soaked up quite a bit and sure gave it a great deep color. The picture I posted was before the Howards.
 
You must log in or register to reply here.
Back
Top Bottom