Author Topic: Wurlitzer 200 amplifier noise  (Read 166 times)

Offline John Steel

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Wurlitzer 200 amplifier noise
« on: August 08, 2018, 05:28:48 AM »
Hello & howdo'?
Thank you for adding me to forum - it's a tremendous resource and I have gained a wealth of knowledge from it already. I live in the SE of England and recently acquired a Wurlitzer 200 which I believe dates to 1971 and while I'm still assessing it for faults and improvements, I can tell it will be a great instrument with some applied care and effort. The biggest problem is the amplifier which is working but is hissy, crackly and generally a bit 'grumbly'.
 Based on experience, can any forum members recommend an amp re-build / repair service in the UK please? Any information would be gratefully received - best wishes, John.

Offline Tim Hodges

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Re: Wurlitzer 200 amplifier noise
« Reply #1 on: August 08, 2018, 06:18:07 AM »
Hi John,

I restore Wurlitzer's in the SW (based in Bristol) is this by any chance the 200 which was for sale at auction recently?

In fact I just realised that I sent you the hardware screws  :)
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Offline Tim Hodges

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Re: Wurlitzer 200 amplifier noise
« Reply #2 on: August 08, 2018, 06:36:17 AM »
In terms of improving the amp there's a few things that can be done.

1) Begin with adding reed shields, I've always found this to be the biggest improvement of reducing noise
2) Re-dressing the power cables, twisting them to reduce electromagnetic radiation and rather than using foil like others I take an aluminium tube and run it across the back of the amp rail (like in the 200a's)
3) Servicing the amp components

Before any of that is done the best thing to check is whether it's the amp or the reed bar which is causing the bulk of your hum. So with the power off, open up the lid of the Wurlitzer, unplug the reed bar RCA connector from the amp and turn on the power, now you can hear the amp through the speakers without the reed bar connected. If it's still noisy then your amp will need going over.

Just a word of caution, the amp is providing a high voltage to the reed bar through that RCA connector so it's always best to have the amp off if you're connecting / disconnecting that cable.
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Offline John Steel

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Re: Wurlitzer 200 amplifier noise
« Reply #3 on: August 08, 2018, 08:15:44 AM »
Thanks for your reply Tim,
Yes, I ordered the screws etc - arrived yesterday and I left positive feedback. Thanks also for the advice re: testing the amp (there's no substitute for experience) and shielding the reeds - it's much appreciated. Yes, I bought it in an auction (which included a Hohner Pianet T in really good condition). I'll have a listen to the amp minus the reed bar. ATB John.

Offline pianotuner steveo

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Re: Wurlitzer 200 amplifier noise
« Reply #4 on: August 09, 2018, 07:34:07 AM »
If the noise goes away, the reed bar needs to be cleaned. Dust,dirt,solder blobs, even condensation can cause these noises among other things such as shorted reeds.
1960 Wurlitzer model 700 EP
1968 Gibson G101 Combo organ
1975 Rhodes Piano Bass
1979 Wurlitzer 206A EP
1980 Wurlitzer 200A EP
1980 Wurlitzer 270 Butterfly Grand
2000 Yamaha acoustic piano
2004 Hammond XK3
2009 73A Rhodes Mark 7
2009 Korg SV-1 73
....and a few guitars...

Offline John Steel

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Re: Wurlitzer 200 amplifier noise
« Reply #5 on: August 09, 2018, 09:47:09 AM »
Thanks for your reply Pianotuner Steveo,
I will most certainly check for those things - I have a little remedial work to do first, replacing the damaged panel mounted IEC power connector and replacing the phono plug on the reed bar cable. ATB John.

Offline Electrickey

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Re: Wurlitzer 200 amplifier noise
« Reply #6 on: August 14, 2018, 03:39:47 AM »
In addition to all the advice mentioned, using a quality heat sensing solder iron when I first got it after having a piano tech adjust the hammers and action, cleaning out the bottom of the case, I carefully re-flowed the amp solder points on my 200A's circuit boards (amp and pre amp) and the thunderstorms stopped. Tightened up the ground spots.

Did not change any parts. It's been fine for a number of years now.

Offline John Steel

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Re: Wurlitzer 200 amplifier noise
« Reply #7 on: August 14, 2018, 11:25:13 AM »
In addition to all the advice mentioned, using a quality heat sensing solder iron when I first got it after having a piano tech adjust the hammers and action, cleaning out the bottom of the case, I carefully re-flowed the amp solder points on my 200A's circuit boards (amp and pre amp) and the thunderstorms stopped. Tightened up the ground spots.

Did not change any parts. It's been fine for a number of years now.

Thanks for your reply Electrickey - That's also great advice. I think I had better invest a high quality iron! Best wishes John.

Offline Electrickey

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Re: Wurlitzer 200 amplifier noise
« Reply #8 on: Yesterday at 12:56:38 AM »

Thanks for your reply Electrickey - That's also great advice. I think I had better invest a high quality iron! Best wishes John.

John if you can, use a good grade of solder. The Wurli deserves the TLC.

Cardas brand gets a lot of thumbs up for audio, easy to flow. It is available in the UK.




You can get 100 gram spools as well. It's a meld of silver, copper, tin & lead.

Or a 3m length sold by xaudiodesign on eBay for about 5 pounds.

https://www.ebay.co.uk/itm/CARDAS-QUAD-EUTECTIC-SOLDER-3m-length-Silver-Copper-tin-Lead-Rosin-core/112317914369?hash=item1a26ab5d01:g:JEAAAOSwjMJXCORu

« Last Edit: Yesterday at 01:04:54 AM by Electrickey »

Offline John Steel

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Re: Wurlitzer 200 amplifier noise
« Reply #9 on: Yesterday at 04:52:11 AM »

Thanks for your reply Electrickey - That's also great advice. I think I had better invest a high quality iron! Best wishes John.

John if you can, use a good grade of solder. The Wurli deserves the TLC.

Cardas brand gets a lot of thumbs up for audio, easy to flow. It is available in the UK.




You can get 100 gram spools as well. It's a meld of silver, copper, tin & lead.

Or a 3m length sold by xaudiodesign on eBay for about 5 pounds.

https://www.ebay.co.uk/itm/CARDAS-QUAD-EUTECTIC-SOLDER-3m-length-Silver-Copper-tin-Lead-Rosin-core/112317914369?hash=item1a26ab5d01:g:JEAAAOSwjMJXCORu




Thanks again Electrickey - It hadn't occurred to me that the type of solder would make a difference!