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Neil
Reply with quote  #1 
Hi guy's
Just finished my Phono Stage build. I have power but no sound any ideas?
I'll try putting some pics up see if it's anything obvious
Thanks
Neil
Reply with quote  #2 
It looks like only the four 6C45Pi are lighting up and not the two 12AX7's if that helps anyone help me.

Neil
carson.
Reply with quote  #3 
Sounds like you have already found the problem. Trace out your heater circuits for those tubes.
Neil
Reply with quote  #4 
Thanks for your reply Carson, being as I'm a bit of a noob how do I go about doing that?
Here are a few pics if anyone can see something that stands out give me a shout please.



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ramon68
Reply with quote  #5 
In the second photo, are 2 diode leads touching?
ramon68
Reply with quote  #6 
I meant the ones at the top of the cluster.
Neil
Reply with quote  #7 
No, it looks like they are but not
Neil
Reply with quote  #8 
Right guy's I've been scratching my head and double checking everything on this, one thing that stands out..
In the Assembly Manual
Page 10
Step four-Chassis Wiring
4A. Solder the choke leads across R2

Now when I check the addendum for photo of completed unit, the choke is soldered across R1 could this be my problem?
Also which one is correct R1 or R2
Thanks
carson.
Reply with quote  #9 
I don't think that is not your problem. Mine are on R2.

Your diode bridge could be built a little neater; lots of looped wire there. Point to point those terminations and clean that up a bit. I don't have the schematic in front of me, and I don't remember if that feeds the 12AX7 heaters or if they all share the same FIL.

Some of your board connections look like they got hot. Check your traces for continuity

Bruce Rozenblit
Reply with quote  #10 
Neil,

I don't want the schematics posted on the internet for this product.  I'm trying to make a living here.


Neil
Reply with quote  #11 
Oops soz Bruce
P@
Reply with quote  #12 
Check the two transformers on the power supply board that are the same size and shape, they look identical but are not.
Bill
Reply with quote  #13 
A bunch of those solder joints in the third picture don't look very good. Many years ago I fixed stereos and we would have units (some kits, some commercial tube preamps) that looked like yours - first thing I would do is reflow/resolder ALL the joints often this would often fix the problem(s), if not I would then trouble shoot.

Good Luck
CharlieM
Reply with quote  #14 
From the photos your build looks acceptable enough to produce sound.  

Of course I say this without checking all the banding on the resistors to ensure you have the correct values in the right positions.  But you have the higher wattage resistors in the right place and it seems you have the capacitors placed correctly and from everything I can see it looks like it was built as it should have been.

Besides the suggestion to check to ensure you have the correct transformers properly placed I would ask you to check your voltage regulators that are mounted on the heat sinks.  You can do this by looking at the part numbers stamped on them.  It may take a magnifying glass to do this.

Without being condescending, they should both be positive voltage regulators and have the same P/N. If one or both are negative voltage regulators you won't get any sound.   Trust me when I tell you this can happen.

Time to get your multimeter out.

The sure way to tell if you have the trannies placed properly while at the same ensuring you have the correct voltage regulators is to take some voltage checks.  Look for approximately 200 volts at pin 7 of V2 and V5.  Look for +12 volts between pins 4 and 5 of V3 and V6 (12AX7s).  Look for +6 volts between pins 4 and 5 of the other four tube sockets (6C45Pi) as those are arranged as two pairs and take 12 volts and divide it between two tubes twice.

If you have the above voltages then the thing is operating correctly and the problem is probably a signal connection (RCAs and twisted pairs, output capacitors, etc.).















Richard Sherman
Reply with quote  #15 
I built this kit.

In my case I installed one of the two smaller transformers backwards and noticed it before powering up the PHONO Stage.

Attempting to remove it was impossible without risking damage to the PC board.

So I simply cut off the leads and removed the pieces from the PC board, then ordered a replacement from Transcendent.

Double check the orientation of these, you may have done the same thing as me.., installed them 180 deg [frown]


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