Author Topic: Twin Reverb with a Rhodes for home use  (Read 1341 times)

Offline alenhoff

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Twin Reverb with a Rhodes for home use
« on: November 22, 2017, 09:40:42 PM »
For years, a recurring topic on this list has been whether a Twin Reverb is too powerful to use at home with a Rhodes, with some folks saying you just can't get a decent tone at home levels.  So here's a contrary point of view:

Today, I found one at a good price and couldn't resist buying it.  Brought it home and thought it sounded wonderful -- clean, bright and full-bodied-- and really helped bring out some extra charm from the Rhodes.  I'm not sure I'd feel the same way if I lived in an apartment with neighbors who didn't appreciate my playing and I had to play it very softly.  But I live in a single family house, and it sounds great in my music room set on about 3.

I wonder whether much of the "you can't get good tone from a Twin at home" comes from guitarists who don't think they have any tone if they're not over-driving an amp. (And over-driving a Twin may well risk your hearing.  Better to add a distortion pedal.) Given the amp's weight and bulk, I'm quite pleased to leave it in my home -- and I won't feel bad that there are 7 volume numbers that I'll never use.

For the record, my new toy is a 1977 Silverface 100 watt version (not the ultralinear 135 watt version), with push/pull master volume.  (I suppose I could use the master volume to get distortion at reasonable volumes, but I prefer a clean Rhodes sound anyway.)

By the way, troubleshooting suggestions would be gratefully accepted for the amp's one issue:  The Vibrato (tremolo) doesn't work. I can hear a little rhythmic clicking, however, that varies in tempo as I turn the speed knob.  And when I turn the depth knob up, it reduces the overall volume of the amp, as if it's shunting the signal to ground. I tried replacing the vibrato tube, which made no difference.

Alan
1974 Rhodes Mark I Stage 73
1972 Rhodes Silver Sparkletop Piano Bass
1978 Hohner Clavinet D6
1968 Hohner Pianet N II
1966 Wurlitzer 140B
1967 Gibson G101 combo organ
1967 Kustom Kombo combo organ
1965 UK Vox Continental
1954 Hammond B2; Leslie 21H; Leslie 31H
1977 Fender Twin Reverb
Vox AD100VT Valvetronix modeling amp
(SEE THE COLLECTION: https://vintagerockkeyboards.wordpress.com/ )

Offline pnoboy

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Re: Twin Reverb with a Rhodes for home use
« Reply #1 on: November 23, 2017, 10:03:29 AM »
For years, a recurring topic on this list has been whether a Twin Reverb is too powerful to use at home with a Rhodes, with some folks saying you just can't get a decent tone at home levels.  So here's a contrary point of view:

Today, I found one at a good price and couldn't resist buying it.  Brought it home and thought it sounded wonderful -- clean, bright and full-bodied-- and really helped bring out some extra charm from the Rhodes.  I'm not sure I'd feel the same way if I lived in an apartment with neighbors who didn't appreciate my playing and I had to play it very softly.  But I live in a single family house, and it sounds great in my music room set on about 3.

I wonder whether much of the "you can't get good tone from a Twin at home" comes from guitarists who don't think they have any tone if they're not over-driving an amp. (And over-driving a Twin may well risk your hearing.  Better to add a distortion pedal.) Given the amp's weight and bulk, I'm quite pleased to leave it in my home -- and I won't feel bad that there are 7 volume numbers that I'll never use.

For the record, my new toy is a 1977 Silverface 100 watt version (not the ultralinear 135 watt version), with push/pull master volume.  (I suppose I could use the master volume to get distortion at reasonable volumes, but I prefer a clean Rhodes sound anyway.)

By the way, troubleshooting suggestions would be gratefully accepted for the amp's one issue:  The Vibrato (tremolo) doesn't work. I can hear a little rhythmic clicking, however, that varies in tempo as I turn the speed knob.  And when I turn the depth knob up, it reduces the overall volume of the amp, as if it's shunting the signal to ground. I tried replacing the vibrato tube, which made no difference.

Alan

Playing at TR at low volume will not destroy the tone.  The TR is designed to put out lots of clean, i.e., low-distortion, sound until it ultimately starts to distort.  Playing softly does not change that in any way.  The human ear's perception of bass frequencies goes down as volume goes down, but that's not a function of the TR.  I would add that for home use, there's nothing that special about a TR.  Its undistorted sound is a function of 2 12" speakers mounted in an open-back cabinet close to the floor, and a frequency equalization in which frequencies around 500 Hz are substantially reduced http://www.duncanamps.com/tsc/.  There are any number of amps that meet those criteria.  BTW, if you want to hear how the TR sounds with a flat frequency response, turn the mid control all the way up, the treble all the way down, and the bass just a touch above all the way down.

I believe this amp uses an optical tremolo, in which a neon bulb changes the resistance of a photoresistor.  The tremolo oscillator is a phase-shift type that uses 3 capacitors in a feedback loop.  If any one of these is bad, the oscillator won't work.  The fact that you hear something probably points to a problem with the neon bulb or photoresistor.  It will be simple for any competent tech to troubleshoot the tremolo--it's a simple circuit.  The biggest problem is hoisting this heavy beast up to the bench and wrestling its chassis out.  BTW, such a tremolo circuit does not put out a smooth tremolo, but rather one that has a sort of pulsing sound.  Personally, I don't care for it, but some people love it.

Offline alenhoff

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Re: Twin Reverb with a Rhodes for home use
« Reply #2 on: November 23, 2017, 11:29:37 AM »
BTW, such a tremolo circuit does not put out a smooth tremolo, but rather one that has a sort of pulsing sound.  Personally, I don't care for it, but some people love it.

I do like the rounder sound of a tremolo circuit that uses incandescent bulbs (like in the Peterson Rhodes amps and my Wurli 140B). Not that I'm about to replace the amp I bought yesterday, but I'm curious: Do you know of any amps that have these kinds of tremolo circuits that are in relatively good supply?  (I'm assuming they would all be vintage amps, but maybe that's not true.)

Thanks for the troubleshooting tips.

Alan
1974 Rhodes Mark I Stage 73
1972 Rhodes Silver Sparkletop Piano Bass
1978 Hohner Clavinet D6
1968 Hohner Pianet N II
1966 Wurlitzer 140B
1967 Gibson G101 combo organ
1967 Kustom Kombo combo organ
1965 UK Vox Continental
1954 Hammond B2; Leslie 21H; Leslie 31H
1977 Fender Twin Reverb
Vox AD100VT Valvetronix modeling amp
(SEE THE COLLECTION: https://vintagerockkeyboards.wordpress.com/ )

Offline pnoboy

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Re: Twin Reverb with a Rhodes for home use
« Reply #3 on: November 23, 2017, 02:30:51 PM »
Modern tremolo circuits use several different techniques.  Using an LED and photoresistor can give a nice smooth sound if designed to do so.  There's nothing special about incandescent bulbs--Peterson used them because that's what was available back then.  Fender uses neon bulbs because they are inherently high-voltage, low-current devices, which match well with tubes.  Much of what you see in guitar amps is driven by cost, not sonic superiority.

Offline The Real MC

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Re: Twin Reverb with a Rhodes for home use
« Reply #4 on: November 23, 2017, 07:28:23 PM »
Twin Reverb is a fine amp for Rhodes at any volume.

You'll get the best tone with the master volume all the way up.  Backing down the preamp level may not be desirable for guitar players but it will work fine with Rhodes.

That amp circuit is actually the same amp in other models - Super Six Reverb, Quad Reverb, Vibrosonic Reverb, and Dual Showman Reverb.  Only difference is the speaker configurations.  Since I use external speaker cabinets, I elected for the Dual Showman Reverb which is the head version of the Twin Reverb.  Much lighter and cheaper.

Offline joostovermars

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Re: Twin Reverb with a Rhodes for home use
« Reply #5 on: November 24, 2017, 10:58:03 AM »
The Fender Princeton Reverb (15 Watts) has a different tremolo circuit: the tremolo signal controls the cathode bias of the output tubes, resulting in a very smooth sine-like tremolo wich I prefer above the neon bulb/LDR combination.
Marshall used a similar circuit in it’s 18 W combo, but there the pre-amp tube cathode is modulated. I plan to experiment with this Marshall design (that uses only one 12ax7 for gainstage and tremolo oscillator) as a Rhodes preamp. It could be powered by a 12V adaptor & a voltage pump.
Music teacher, keyboard player
Hammond A100 & Leslie 145 1969 (restored)
Rhodes 73 mk1 1977 (restored)
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Nord Electro 5D & Leslie 2101 mk2
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Offline alenhoff

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Re: Twin Reverb with a Rhodes for home use
« Reply #6 on: November 24, 2017, 07:07:17 PM »
A tech diagnosed the vibrato/tremolo issue as having this odd source:  Someone apparently burned the insulation on a cap in the vibrato circuit by hitting it with a soldering iron, and it was shorting out.  Replaced the cap and we have vibrato.

Alan
1974 Rhodes Mark I Stage 73
1972 Rhodes Silver Sparkletop Piano Bass
1978 Hohner Clavinet D6
1968 Hohner Pianet N II
1966 Wurlitzer 140B
1967 Gibson G101 combo organ
1967 Kustom Kombo combo organ
1965 UK Vox Continental
1954 Hammond B2; Leslie 21H; Leslie 31H
1977 Fender Twin Reverb
Vox AD100VT Valvetronix modeling amp
(SEE THE COLLECTION: https://vintagerockkeyboards.wordpress.com/ )

Offline armstrongsound

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Re: Twin Reverb with a Rhodes for home use
« Reply #7 on: November 27, 2017, 01:08:25 PM »
Not that anyone asked, but I play through a '68 Vibrolux Reverb.

To me that is the perfect amount of oomph with the perfect amount of headroom for the home. (Not a whole lot, but not so little that it goes straight into OD)

OF course, I like my tone to be a little more "colorful" than most.

1970 Fender Rhodes Mk I Seventy-Three Suitcase (no suitcase amp)
1968 Fender Vibrolux (aa864 circuit)
1969 Hammond T202
1956 Hammond S6
1982 Kustom 88
90s Young Chang Upright
Hohner Melodica

Offline pnoboy

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Re: Twin Reverb with a Rhodes for home use
« Reply #8 on: November 28, 2017, 09:08:59 AM »
Not that anyone asked, but I play through a '68 Vibrolux Reverb.

To me that is the perfect amount of oomph with the perfect amount of headroom for the home. (Not a whole lot, but not so little that it goes straight into OD)

OF course, I like my tone to be a little more "colorful" than most.

Not a whole lot of headroom for the home?  That amp should be able of blasting your eardrums in a home setting!  :->  I once worked with a guitarist who used that amp, and it was plenty loud in function halls.

Offline 4kinga

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Re: Twin Reverb with a Rhodes for home use
« Reply #9 on: November 28, 2017, 03:26:09 PM »
I play my '73 through a PR-40 at home.  I found an amp from a suitcase and wired that in.  Always said I was going to make a circuit for the triple necklace reverb.  Still haven't got around to that one, yet.

Offline armstrongsound

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Re: Twin Reverb with a Rhodes for home use
« Reply #10 on: November 30, 2017, 04:28:45 PM »
@pnoboy

When I say "headroom" I'm referring to the amount of clean gain attainable before the signal drives the tubes, not just the volume.

You are absolutely correct. The amp pretty much shakes the foundations at 5!

1970 Fender Rhodes Mk I Seventy-Three Suitcase (no suitcase amp)
1968 Fender Vibrolux (aa864 circuit)
1969 Hammond T202
1956 Hammond S6
1982 Kustom 88
90s Young Chang Upright
Hohner Melodica

Offline conroy

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Re: Twin Reverb with a Rhodes for home use
« Reply #11 on: April 23, 2018, 04:01:21 AM »
Congratulations on the Twin! Hope you're still enjoying it. The Rhodes/Twin combo is a match made in heaven. Buckets of clean sound at any volume. The Twin can easily showcase all the extreme lows and highs your electric piano is capable of.

Glad you got the tremolo problem solved. The Twin's opto tremolo is well suited for the Rhodes.

Have you had a look inside of your Twin yet? I would highly recommend getting a cap job if it hasn't already been done. It will definitely breath some new life into it.

When you're ready for new tubes check out the Tubestore; http://www.thetubestore.com/ I've had good experiences dealing with them. They are very professional. I've rolled a lot of tubes and my favorite of the "affordable" power tubes are the Tung-Sol 6L6GC-STR. They are very well suited for the Twin.


Offline alenhoff

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Re: Twin Reverb with a Rhodes for home use
« Reply #12 on: April 23, 2018, 08:15:42 AM »
I'm definitely loving the Twin.  I'm taking the signal directly off the harp of my '74 Stage, and the sound is wonderful.

The amp was re-capped before I bought it. My tech says it's putting out its full rated power (and it's quiet), so I guess the tubes are fine. The tech said he'd replace the speakers (a pair of original Fender-branded Rolas that are in great shape), but he's a guitar guy. ;-)  I can't imagine that at the clean, home volume levels I use that replacing the speakers would make any difference to me.  I do like to keep things original, too, when I can.

Alan

1974 Rhodes Mark I Stage 73
1972 Rhodes Silver Sparkletop Piano Bass
1978 Hohner Clavinet D6
1968 Hohner Pianet N II
1966 Wurlitzer 140B
1967 Gibson G101 combo organ
1967 Kustom Kombo combo organ
1965 UK Vox Continental
1954 Hammond B2; Leslie 21H; Leslie 31H
1977 Fender Twin Reverb
Vox AD100VT Valvetronix modeling amp
(SEE THE COLLECTION: https://vintagerockkeyboards.wordpress.com/ )

Offline conroy

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Re: Twin Reverb with a Rhodes for home use
« Reply #13 on: May 08, 2018, 12:55:56 AM »
Glad you've got some good electrolytic caps in there. Definitely worth having on an amp of this vintage.

Love playing the Rhodes through the tremolo effect on this amp. How are you finding the quality of the tremolo? If you play a sustained bass note with the tremolo intensity cranked, do you hear a slight chopping or ticking sound?

The Rolas aren't bad but you might get a wider more Rhodes friendly range with a pair of JBLs or EVs in the Twin.

Offline alenhoff

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Re: Twin Reverb with a Rhodes for home use
« Reply #14 on: May 08, 2018, 06:51:55 AM »
My tech did two mods on my amp:

1) When I got it, the tremolo was ticking quite noticeably, even when I was not playing.  This is apparently a very common issue on Fender amps of the era, and is addressed by Fender Service Bulletin #9 by adding a cap and re-dressing some wires. Take a look here: https://bb.steelguitarforum.com/viewtopic.php?t=311528&sid=0d5cf653e28eef77571d7b6410a1b16d

2)  He also made a mod in the reverb circuit that he said cured a "blown speaker" kind of sound that I might hear on sustained bass notes with the reverb on. I don't know what this mod included.

My only slight gripe about the tremolo is that I think it is a bit too fast for what I want to hear with the Rhodes. (I generally have the speed set near its slowest setting.)  I know there are ways to modify this, too, but I've decided that it's probably good enough as is.

Alan

1974 Rhodes Mark I Stage 73
1972 Rhodes Silver Sparkletop Piano Bass
1978 Hohner Clavinet D6
1968 Hohner Pianet N II
1966 Wurlitzer 140B
1967 Gibson G101 combo organ
1967 Kustom Kombo combo organ
1965 UK Vox Continental
1954 Hammond B2; Leslie 21H; Leslie 31H
1977 Fender Twin Reverb
Vox AD100VT Valvetronix modeling amp
(SEE THE COLLECTION: https://vintagerockkeyboards.wordpress.com/ )

Offline pnoboy

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Re: Twin Reverb with a Rhodes for home use
« Reply #15 on: May 08, 2018, 11:30:13 AM »
Glad you've got some good electrolytic caps in there. Definitely worth having on an amp of this vintage.

Love playing the Rhodes through the tremolo effect on this amp. How are you finding the quality of the tremolo? If you play a sustained bass note with the tremolo intensity cranked, do you hear a slight chopping or ticking sound?

The Rolas aren't bad but you might get a wider more Rhodes friendly range with a pair of JBLs or EVs in the Twin.

Yeah, but then you'll need a forklift to move your Twin Reverb around!  LOL

Offline alenhoff

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Re: Twin Reverb with a Rhodes for home use
« Reply #16 on: May 15, 2018, 01:13:25 PM »
My only slight gripe about the tremolo is that I think it is a bit too fast for what I want to hear with the Rhodes. (I generally have the speed set near its slowest setting.)  I know there are ways to modify this, too, but I've decided that it's probably good enough as is.

I changed my mind, and made the mod.  With help from an electronics forum, I learned there are three caps in series in the Twin's tremolo circuit: A 0.02 uf, and a pair of 0.01uf caps.  I changed the value of the two 0.01 caps to 0.02 and it slows the tremolo to a far more useful range.  The lowest speed is now, for lack of a better description, like a slow heartbeat.  And the fast speed is still a blur.  (Just to make sure that the mod would be apparent to a new buyer if I ever sell it, I added the additional capacitance by paralleling additional caps, rather than swapping out the original caps.

I highly recommend this mod to owners of Twins and other Fender amps that share this tremolo circuit. And a reminder to all:  Make sure you discharge the filter caps before working on a tube amp!

Alan

1974 Rhodes Mark I Stage 73
1972 Rhodes Silver Sparkletop Piano Bass
1978 Hohner Clavinet D6
1968 Hohner Pianet N II
1966 Wurlitzer 140B
1967 Gibson G101 combo organ
1967 Kustom Kombo combo organ
1965 UK Vox Continental
1954 Hammond B2; Leslie 21H; Leslie 31H
1977 Fender Twin Reverb
Vox AD100VT Valvetronix modeling amp
(SEE THE COLLECTION: https://vintagerockkeyboards.wordpress.com/ )

Offline conroy

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Re: Twin Reverb with a Rhodes for home use
« Reply #17 on: May 25, 2018, 02:16:35 AM »
Great that your tech was able to cure the tremolo tick. I'm still attempting to address that issue on my old Twin. I'm about to change the tube ground and hopefully that will solve it.

Good that you slowed the tremolo down. That's definitely a mod I would recommend.

Yeah, it's a heavy amp but it's worth it for all that clean headroom and amazing bass response. I like having the bass, mid and treble controls for the Rhodes.

Offline alenhoff

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Re: Twin Reverb with a Rhodes for home use
« Reply #18 on: May 25, 2018, 06:57:54 AM »
Great that your tech was able to cure the tremolo tick. I'm still attempting to address that issue on my old Twin. I'm about to change the tube ground and hopefully that will solve it.

Check the link in one of the previous posts in this thread to see the Fender Service Bulletin on this issue, which suggested adding a cap in the vibrato circuit and re-dressing some leads.

Alan
1974 Rhodes Mark I Stage 73
1972 Rhodes Silver Sparkletop Piano Bass
1978 Hohner Clavinet D6
1968 Hohner Pianet N II
1966 Wurlitzer 140B
1967 Gibson G101 combo organ
1967 Kustom Kombo combo organ
1965 UK Vox Continental
1954 Hammond B2; Leslie 21H; Leslie 31H
1977 Fender Twin Reverb
Vox AD100VT Valvetronix modeling amp
(SEE THE COLLECTION: https://vintagerockkeyboards.wordpress.com/ )