Author Topic: My amp is LOUD and the tremolo drives up the gain  (Read 2318 times)

Offline funkylaundry

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My amp is LOUD and the tremolo drives up the gain
« on: December 01, 2016, 08:20:51 AM »
I'm surprised how loud the amp in my 200a is. It is an original amp, but it is pretty clear that it has had some work done to it in the past. It's actually pretty good in terms of noise, but I mostly use it running directly into my audio interface and the output level is way beyond line level. At least if the tremolo is on. And that is the weird thing. When I turn up the tremolo the gain is turned up as well. Is that normal? I don't remember seeing this on my 200 while I still had the original amp in and with the Retrolinear amp some overall level is lost when turning up the tremolo (i.e. the gain is probably the same but the impression of loudness is not).

The thing is, as it is now, I can only turn the volume pot up around half-way before it starts clipping my mic preamps. In turn this means a worse signal to noise ratio and when I start using compression that results in some not so pleasant artifacts in the signal. I even have the gain trim on the PCB turned way down to the lowest setting.
'72 Fender Rhodes MkI Stage, '73 Wurlitzer 200, '72 Clavinet D6, '75 Hammond B-3, '71 Leslie 147, Hammond X5, Leslie 710, Nord Stage 2 73SW, Moog Sub 37, DSI Mopho X4, DSI Tetra

Offline pianotuner steveo

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Re: My amp is LOUD and the tremolo drives up the gain
« Reply #1 on: December 01, 2016, 09:01:45 AM »
I was going to suggest turning that trim pot down, but you already have. Are you using the headphone output or the AUX  jack? There should be another trim pot near the output jacks, have you tried turning that down?

If that doesn't help,then maybe it was modified. It sounds like you need to trim down the output at the AUX Jack. A large resistor in series with the output would help too, but a trim pot would be better if yours is missing or broken.

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 cinnanon

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Re: My amp is LOUD and the tremolo drives up the gain
« Reply #2 on: December 01, 2016, 11:43:39 AM »
When I turn up the tremolo the gain is turned up as well. Is that normal? I don't remember seeing this on my 200 while I still had the original amp in and with the Retrolinear amp some overall level is lost when turning up the tremolo (i.e. the gain is probably the same but the impression of loudness is not).

The thing is, as it is now, I can only turn the volume pot up around half-way before it starts clipping my mic preamps. In turn this means a worse signal to noise ratio and when I start using compression that results in some not so pleasant artifacts in the signal. I even have the gain trim on the PCB turned way down to the lowest setting.

I've noticed the same thing in all 200A amps. What I like about the Retrolinear amp is that it doesn't do that. It sort of caps the gain/volume/level/loudness (whatever it is) where you think it should be (not any louder than with the tremolo off).

Offline funkylaundry

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Re: My amp is LOUD and the tremolo drives up the gain
« Reply #3 on: December 02, 2016, 07:55:42 AM »
I was going to suggest turning that trim pot down, but you already have. Are you using the headphone output or the AUX  jack? There should be another trim pot near the output jacks, have you tried turning that down?

If that doesn't help,then maybe it was modified. It sounds like you need to trim down the output at the AUX Jack. A large resistor in series with the output would help too, but a trim pot would be better if yours is missing or broken.

You're right! I had accidentally plugged it into the headphone output. Using the aux output made it much more manageable. And apparently there is a trim for the aux output as well that is not present on 200 models.
'72 Fender Rhodes MkI Stage, '73 Wurlitzer 200, '72 Clavinet D6, '75 Hammond B-3, '71 Leslie 147, Hammond X5, Leslie 710, Nord Stage 2 73SW, Moog Sub 37, DSI Mopho X4, DSI Tetra

Offline funkylaundry

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Re: My amp is LOUD and the tremolo drives up the gain
« Reply #4 on: December 02, 2016, 07:57:44 AM »
When I turn up the tremolo the gain is turned up as well. Is that normal? I don't remember seeing this on my 200 while I still had the original amp in and with the Retrolinear amp some overall level is lost when turning up the tremolo (i.e. the gain is probably the same but the impression of loudness is not).

The thing is, as it is now, I can only turn the volume pot up around half-way before it starts clipping my mic preamps. In turn this means a worse signal to noise ratio and when I start using compression that results in some not so pleasant artifacts in the signal. I even have the gain trim on the PCB turned way down to the lowest setting.

I've noticed the same thing in all 200A amps. What I like about the Retrolinear amp is that it doesn't do that. It sort of caps the gain/volume/level/loudness (whatever it is) where you think it should be (not any louder than with the tremolo off).

At first I was like "oh, that's a cool feature", because even though the peaks may stay the same, once you add tremolo it appears more silent, but now I realize that they overcompensate WAY too much. It's maybe 15dB louder with tremolo engaged than without. It's allright for studio use, where you can gain stage easier, but for live use I might consider using a tremolo pedal instead.
'72 Fender Rhodes MkI Stage, '73 Wurlitzer 200, '72 Clavinet D6, '75 Hammond B-3, '71 Leslie 147, Hammond X5, Leslie 710, Nord Stage 2 73SW, Moog Sub 37, DSI Mopho X4, DSI Tetra

Offline funkylaundry

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Re: My amp is LOUD and the tremolo drives up the gain
« Reply #5 on: December 08, 2016, 08:14:31 AM »
Vintage Vibe just posted this nice interactive graphic to identify Wurlitzer parts:

http://www.vintagevibe.com/blogs/news/wurlitzer-200a-parts-diagrams

Nice work on their part, but what's actually more interesting to me than the graphic itself is the text where they outline the differences between 200 and 200A. Among other things they say:

Quote
"Wurlitzer updated the amplifier once again by placing the pre amp on top of the harp to reduce noise. They also used an LDR for the vibrato instead of modulating the pre amp gain with reactance modulation."

Interesting. What does LDR stand for - how is it different than modulating the gain?
'72 Fender Rhodes MkI Stage, '73 Wurlitzer 200, '72 Clavinet D6, '75 Hammond B-3, '71 Leslie 147, Hammond X5, Leslie 710, Nord Stage 2 73SW, Moog Sub 37, DSI Mopho X4, DSI Tetra

Offline sean

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Re: My amp is LOUD and the tremolo drives up the gain
« Reply #6 on: December 08, 2016, 11:55:16 AM »

LDR is Light Detecting Resistor, or Light Dependent Resistor, or Photoresistor.

Flash a lightbulb in front of the LDR, and the LDR resistance goes down.  Turn off the light, and the LDR resistance goes back up. Blink the light on and off repeatedly, and you get tremolo.

S

Offline Jenzz

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Re: My amp is LOUD and the tremolo drives up the gain
« Reply #7 on: December 08, 2016, 02:01:37 PM »
On the 200A amp board, the volume change when turning up Tremolo can be adjusted with the red trimmer in the back left side, right before the heat sink. Turning it left will lower the amount of volume change...

Jenzz

Offline funkylaundry

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Re: My amp is LOUD and the tremolo drives up the gain
« Reply #8 on: December 26, 2016, 04:30:57 PM »
Thanks, Jenzz. That helped greatly. I had turned all of the way to the left thinking it was the preamp volume and given that everything was too loud (I was using the headphone jack by mistake) I was trying to turn it down.

You play vibraphone?
'72 Fender Rhodes MkI Stage, '73 Wurlitzer 200, '72 Clavinet D6, '75 Hammond B-3, '71 Leslie 147, Hammond X5, Leslie 710, Nord Stage 2 73SW, Moog Sub 37, DSI Mopho X4, DSI Tetra

Offline Jenzz

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Re: My amp is LOUD and the tremolo drives up the gain
« Reply #9 on: January 05, 2017, 03:00:18 AM »
You play vibraphone?

Yes, i returned to Vibes some years ago, having played these back in the 80's in school. But also own a 200A and VV 64 Classic (probably i'm the only Rhodes tech that doesn't own a Rhodes anymore... :-) ).

regards, Jens .-)

Offline funkylaundry

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Re: My amp is LOUD and the tremolo drives up the gain
« Reply #10 on: January 14, 2017, 07:02:34 PM »
Nice. I used to have a Trixon Tonemaster from the 60's. You're german, so you probably know them. Amazing design, great tone. I picked it up at a time when my life was turning towards other things than music, though, so I never got to practice much on it. In the end I just had it in storage. Sold it last year to a friend who is using it every day to make records and I used the money to buy my first Wurlitzer, so I'm pretty happy that it found more love elsewhere. But there is certainly some of the same character in vibraphone as in vintage keyboards like Rhodes and Wurlitzer.
'72 Fender Rhodes MkI Stage, '73 Wurlitzer 200, '72 Clavinet D6, '75 Hammond B-3, '71 Leslie 147, Hammond X5, Leslie 710, Nord Stage 2 73SW, Moog Sub 37, DSI Mopho X4, DSI Tetra

Offline Ben Bove

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Re: My amp is LOUD and the tremolo drives up the gain
« Reply #11 on: January 17, 2017, 01:58:40 PM »
It may be unrelated, but I had a Wurlitzer 200 that had the vibrato pot terminals shorted against each other, and vibrato would cut in and out - and when it cut out, it drove up the gain of the piano.  Might not be related, but I just carefully separated the pot terminals and wirings.
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