Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: navdave on August 15, 2010, 10:01:28 pm
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Is there anywhere I can get an optoisolator for a Deluxe Reverb clone? Or is there an alternative way to do it without using an opto?
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The alternative without the Opto-isolator would be a whole Hoffman AB763 board which uses a different Trem (vib) design.
j.
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The vibe has a different sound than the trem correct?
I love the way the Deluxe Reverb sounds.
The alternative without the Opto-isolator would be a whole Hoffman AB763 board which uses a different Trem (vib) design.
j.
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Thanks for the heads up gonna check those sites.
triodeelectronics, or mojomusicalsupply, or many more (dot coms)
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weber has them and even has parts to make your own....
https://taweber.powweb.com/store/chansword.htm (https://taweber.powweb.com/store/chansword.htm)
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Use an LED instead of the neon bulb.Smoother,better tone from the trem.
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The vibe has a different sound than the trem correct?
I love the way the Deluxe Reverb sounds.
The alternative without the Opto-isolator would be a whole Hoffman AB763 board which uses a different Trem (vib) design.
j.
What I meant by this is: Fender's Vibrato is actually Tremolo (volume fluctuation). The only tube amps with pure vibrato (note pitch bending) that I know of are old Magnatone amps.
So I said Trem for what it actually is, and (vib) for what Fender labeled it on that particular amp.
The Hoffman AB763 does Trem but without the Opto, instead using a different circuit to acheive the same result. The Opto Trem is noted to have a "ticking" sound where the oscillator (as employed by Hoffman) type has does not. Some like one, some like the other.
j.
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radio shack has parts to build your own, too.\
just use a solar cell and whatever light source you want, and some shrink tubing.
Not really.
Many years ago I spent a bunch of time developing an opto after they became unavailable because of the hazardous material used in the cadmium cell
I ordered 10 different NOS opto's and different bulbs
I kept carefull records when I assembled them as to which opto and bulb were used.
Then they all got installed in a Fender and tested by me listeneing to how they sounded
There was a huge difference in sound between the opto's and bulb combo's
Even the position of how you assembled the bulb next to the cell made a big difference.
Some worked fine, some were not acceptable, some sounded better than original Fender opto's
I made them for many years until the supplies ran out.
I even sold the formula to New Senser and they built and sold them for many years.
You could get lucky and just grab random parts and hope for the best
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Use an LED instead of the neon bulb.Smoother,better tone from the trem.
What do you call the light sensitive resistor? I was trying to find an appropriate part on Mouser and came up empty. IRRC the whole assembly sometimes is called an "optocoupler". Is that correct? There seem to be some self-contained solid state units...
At the risk of hi-jacking this thread, I'm confused about how the LDR works in the AB763 tremolo. Here's a pic of the insides of the "roach" from AES:
(http://www.tubesandmore.com/cemirror/inv/vibrato_ldr.gif)
Here's the AB763 schematic:
http://www.el34world.com/charts/Schematics/fender/DELUXE_REVERB_AB763.pdf
When the light is turned on by the tremolo circuit, does the wiper of the Intensity pot get grounded? IOW does the resistance of the light-sensitive resistor drop to zero?
Thanks for any edumacation you all can offer.
Chip
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I even sold the formula to New Sensor and they built and sold them for many years.
So what do you think New Sensor is selling now? They have opto's on their website. I purchased some from antique electronics and when you turn up the vibrato intensity control, it reduces the overall volume as it increases the effect level. This issue is mentioned here:
http://www.clarkhuckaby.com/fendervib.html
I'd like to get some that don't do this.
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What do you call the light sensitive resistor?
photoresistor or photocell resistor or photo sensitive resistor... or the best one is light dependent resistor LDR and wouldn't you know there would be some on fleabay
http://shop.ebay.com/i.html?_nkw=photocell+resistor (http://shop.ebay.com/i.html?_nkw=photocell+resistor)
this is a good optocoupler http://www.newark.com/jsp/search/productdetail.jsp?SKU=43F885&CMP=AFC-GB100000001 (http://www.newark.com/jsp/search/productdetail.jsp?SKU=43F885&CMP=AFC-GB100000001)
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this is a good optocoupler http://www.newark.com/jsp/search/productdetail.jsp?SKU=43F885&CMP=AFC-GB100000001 (http://www.newark.com/jsp/search/productdetail.jsp?SKU=43F885&CMP=AFC-GB100000001)
Yep but that's not the best price out there. The price here is a little better:
http://www.alliedelec.com/search/productdetail.aspx?SKU=980-0700
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So what do you think New Sensor is selling now
I am guessing that they now use Chinese parts.
Just a guess, but New Sensor, Mojo and everyone else stopped selling opto's back when the parts were scarce.
I had a surplus of parts on hand and was able to build them until the parts ran out.
New Sensor purchased my formula and made their own until the supplies ran out.
Now it looks as though they are all able to get parts again and my best guess is China because they don't care about hazardous materials.
The history goes like this
Opto's were made here for many years and the parts were available
Opto's stopped being made here because of the cadmium
All the stock ran out and no one could make opto roaches
Someone started making the parts again
Opto roaches are now available again
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I purchased some from antique electronics and when you turn up the vibrato intensity control, it reduces the overall volume as it increases the effect level. This issue is mentioned here:
yeah, well they probably did not do their homework like I did.
Some I tested dipped the volume way too low
Some did not dip far enough
Some sounded really good and performed excellent
I have several left here from my testing period that did not work that great
Every light sensitive resistor has different specs
Every neon buld has different specs
To get the volume to swell up and down in the proper zone, you have to use the correct parts
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Well I ordered a few of the Perkin Elmer VTL5C1 vactrols and I'll see how they do. I'm afraid this is like buying a pig in a poke. It would be nice to know one vendor carries good ones. (hint hint Doug)
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When you find a good one, let me know.
I have no idea who has what or how they sound
I only buy from New Sensor and Mojo, so it would be great if one of those two had a good one now.
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If I'm not mistaken the VTL5C1 cant handle 345VDC am I missing something?
Well I ordered a few of the Perkin Elmer VTL5C1 vactrols and I'll see how they do. I'm afraid this is like buying a pig in a poke. It would be nice to know one vendor carries good ones. (hint hint Doug)
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If I'm not mistaken the VTL5C1 cant handle 345VDC am I missing something?
It's not the voltage but the voltage drop. If we can use and LED, we should be able to use this. We'll find out soon enough.
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I have 5 of those LDR's lying around. Are you gonna run a test or something?
It's not the voltage but the voltage drop. If we can use and LED, we should be able to use this. We'll find out soon enough.
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I have 5 of those LDR's lying around. Are you gonna run a test or something?
Yes indeed. I am going to put one in the BFDR I just built and see how it does. I am supposed to receive them on Monday (23rd) but it will probably be later in the week before I pop one in. I'll let you know how it goes. :smiley:
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Cool!
Yes indeed. I am going to put one in the BFDR I just built and see how it does. I am supposed to receive them on Monday (23rd) but it will probably be later in the week before I pop one in. I'll let you know how it goes. :smiley:
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Sorry to dig up this old thread, but does anyone have more info on being able to substitute a fewer 'bug' for a VTL5C1? I have found a couple threads where people have talked about it, but no final conclusions. Thanks
Tim
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http://sluckeyamps.com/trem/trem.htm
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An LED, a LDR and some heat shrink tube. All for less than a $.. and works superb!!!
But then again.. ain't nothin ' like bias vary trem in my world
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Is there anywhere I can get an optoisolator for a Deluxe Reverb clone?
yes, here
https://hoffmanamps.com/MyStore/catalog/Lamps.htm
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I have used the Sluckey Tremonator in an AB763 circuit and like it a lot. It results in a smoother modulation. Steve's drawings are easy to follow.