wurlitzer 206a hiss

[cc0919]

Hello folks,

I've got a 206a that has been chopped and has a connection from the amp out pin to a headphone jack on the bottom left. I've had problems with static and such in the past, but it seems like I've ironed this out. However, I have a TON of unmanageable hiss. No hum or anything, just hiss. I'm just going straight into a mixer with this jack...I've tried putting a dummy load on the line and it didn't help. The interesting thing is that as I decrease the wurli's volume, with the volume pot, the hiss gets significantly louder.

Any ideas?

[pianotuner steveo]

Did someone put a large resistor in line with this jack to reduce the signal? If so, they may have used one that was too large and decreased the signal too much.

Just a guess..

[cc0919]

Nope, no resistors between the amp out and the jack

[cc0919]

I don't know if this is helpful, but I get about the same amount of noise when going from the aux out pin to the jack as I do from going from the amp out pin to the jack

[pianotuner steveo]

You could have a bad volume pot...

[Max Brink]

Can you describe the hiss any more? Hiss could be caused by a ton of different factors...

Are you using the normal 1/4" output from the bottom of the 206A or did you install the aux output components that are shown in the schematic? The latter route will produce the best results if you did not go that route. If you did go that route I would ask whether or not you added the 100K potentiometer or what value of resistor or jumper wire you used (between the volume pot and output components around point 9 on the schematic).

[cc0919]

Hi Max, I haven't installed the aux out components, it is just straight from the pin to the jack. The jack is a regular jack. I'll give describing the hiss a try...it sounds kind of like a tape recorder actually. It is very loud when the volume is down, and as increase the wurlitzers volume it gets noticeably quieter, but is still very loud. If it will help, I can upload a clip when I get home from work this afternoon

[pianotuner steveo]

Have you turned the trim pot on the amp board itself? Maybe it needs to be turned up. Do this with out power on unless you have a plastic screwdriver.( to prevent slipping and accidentally shorting something)

[cc0919]

There are two on my board, one near the front (i assume this is the preamp pot) and one in the back. I adjusted both and it didn't seem to have much of an effect, other than when I turned the preamp one up past 4/5 or so I got crazy crackling and no other sound

[pianotuner steveo]

Max is better with the electronics portion than I am. Any more ideas Max??

[Max Brink]

There are two [trimmer pots] on my board, one near the front (i assume this is the preamp pot) and one in the back. I adjusted both and it didn't seem to have much of an effect, other than when I turned the preamp one up past 4/5 or so I got crazy crackling and no other sound

The front trimmer pot seems to be malfunctioning but it may or may not be directly related to the hiss. The hiss could be a number of things but it is likely to be in the preamplifier if it's coming through both the output and speakers but it's impossible to say where it is coming from without more information or being able to sit down with it in person...

[cc0919]

Max, just for clarification I meant 4/5ths of the way up, not 4 or 5 o clock. I understand that it is tough to diagnose these without looking at them...would it help for me to upload a clip? Also, I was looking at the preamp (i actually have another one) and it looks like there is a connection from the ground to something else with a resistor between it, which my current preamp doesn't have.

[cc0919]

Just wanted to post a quick update - I've decided to stop wrestling with the wurli and bought one of the Warneck 200a amps replacements from RetroLinear. Very excited for it to get here, can't wait to see how it sounds!

[pianotuner steveo]

That is great, but keep your old amp in case anyone wants to buy it from you in the future. Don't just toss it out!