LA-2A point to point build Sowter TXF

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HI,

getting compression and audio signal on output when putting in waveform on input.
Plugged into patch bay and very distorted.
A few voltages are are off, need to do a few more tweaks but nearly there with this now.

regards

Spence.
 
Hi,

Getting some weird voltages on V2' anyone got any ideas?

V1
Pin1 = 102v
Pin3 = 0.840v
Pin6 = 112.5v
Pin8 = 1.059v

V2
Pin1 = 68v
Pin2 = -34.4v
Pin3 = 3.8v
Pin6 = 214v
Pin7 = 35v
Pin8 = 79.6v

V3
Pin1 = 99.3v
Pin3 = 0.728v
Pin6 = 99.3v
Pin8 = 0.729v

V4

Pin2 = 7v
Pin5 = 126.5v
Pin6 = 74.3v

B+ 260v
58.4v @ Zener diode

Regards

Spence
 
With the sowter xfmr, you should put a grid stopper. For your weird values, there can be a lot of reasons, but check you're wiring along with the schematic or the layout. 9 time out of 10 it's due to a mistake somewhere. Check your résistors values, too
 
Hi,

Testing properly tomorrow, but now the OEP Input TXF has been wired correctly and I've included the stereo link bits the circuit works as intended. Still a bit of hum but that should go once top of case in put on.
Will put up some audio samples to see what you think.

Regards

Spence.
 
hi,

still far from right this unit, has hum at about 120hz, putting music through the unit distorts the bottom end, top end and mid range seem fine, just when bass guitar and kick totally distorts?
could this be the OEP not being able to handle it?

regards

Spence.
 
HI,

just changed over the output TXF for another OEP A262A3E wired in series and it all works great!!!!
very nice sound indeed!! just need to order those sowters eventually but to be honest apart from a little hum which is audible from the unit i might leave the OEP's in for a while. It must be an unhappy power TXF that the hum is coming from.
It is a really great sound, very happy.

regards

Spence.
 
Hi,

Anyone have any suggestions on reducing the hum on the output?
It's it sort of acceptable, but noticeable when eqing the low end around at 100-120hz.
I'm hoping once I get this toroidal the acoustic level of the hum from transformer in the case will be gone but I'm going to assume that the hum on the output will still be there.
Just would like some options to try to reduce this as best as I can as this is sounding really great.
Gonna have to build another one now so I've got a stereo pair!!!
Total cost for this has been around £255.

Regards

Spence.
 
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