Spring Reverb in Guitar Amps | Fazio Electric

[@willhouse]

My Dad was late to his very first date with my Mom because he spent too long putting a reverb tank into his '68 Pontiac. She wasn't all that impressed by it, but she liked everything else about him so here I am. 🎶

[@michaelyolch79]

HAHA!!!

[@edgarcook9607]

Yeah, JC Whitney catalog item before there was Stereo...

[@kbjerke]

I began playing guitar in the 1960s LOL! Reverb was an unobtainable dream for such as I, back then. So I attempted to make a poor man's version with a microphone in a steel waste paper basket, that I played my guitar close to - amplified by a really cheap guitar amp. It WORKED!! Horribly. But I didn't give up, and continued my journey into guitar playing. I currently have only one amp, a Harvard Reverb II, and it's OK, but I dream of having a vintage tube amp like I once had. Just for memories. Thanks for the video!

[@ToneObsessed]

The reverb tank has one preferred orientation in a combo amp -- the INPUT side of the tank should be nearest to the power transformer. The input side of the tank is very low impedance, this helps reduce hum pickup from the power transformer. If you flip the tank around, you will get more hum in the reverb signal as the higher impedance of the OUTPUT side of the tank (which is connected to the grid of the recovery triode) is more susceptible to hum pickup.

[@mikebrown9850]

My first amp was a 1977 Peavey Classic 212. It was incredible! I had it reprinted after about 20 years. It never sounded the same! I miss those vintage amps!

[@goodun2974]

The cardboard strip on the bottom of the reverb tank also prevents the bag from bunching up sufficiently to touch the springs and dampen or impede their vibration. Some reverb tanks have a hand operated lever that will lock the springs in place for transport ---- often seen in Leslie speakers or organ "tone cabinets" eith reverb ---- and to prevent the springs falling off or breaking (the little hooks attaching the springs to the transducers sometimes break from shock); this would be a good idea for all guitar amps with reverb, but unfortunately the locking levers can be impractical when you also want a bag around the tank to dampen speaker vibrations and prevent feedback.

[@mikegraves6070]

I bought a new Ampeg V-22 in the mid ‘70’s that has a reverb lock for my Rhodes. Later I discovered that my Clav sounds nice through that old amp.

[@goodun2974]

​​@@mikegraves6070, that's a VT-22 I presume; a combo version of the V4 guitar-amp head. I've seen pictures of Keith Richards playing through one in the studio. And yes, I bet it worked quite well as a keyboard amp since that series of Ampeg amps had tons of clean power and hifi style Baxandall tone controlls..

[@goodun2974]

@@user-zx5gg8od6l, First of all, look up the specs online for the reverb tank, using the code number stamped on the chassis, like 4A-something. If it's a Fender style reverb tank designed to be driven off of a small Champ style output transformer, then it definitely won't work with a line level source going into it ( Those tanks have an extremely low input impedance of 8 ohms at audio frequencies and the measurable DC resistance is about 1 ohm or less ---- It will appear to be a dead short circuit to a line level source). If it's a tank designed to be run from a capacitor driven circuit then the impedance at audio frequencies will be higher and tmeasurable resistance will probably be higher as well but even then at minimum you would have to bend with limit the audio signal going into the tank because you really don't want to be feeding at any base frequencies; also the amount of current needed to drive those tanks is in the milliamp range, and a line level source might provide more voltage and current than that and burn out the element unless you add some series resistance or capacitance or some kind of appropriate network on the input line to limit current, voltage and audio frequencies so you won't overload or damage the transducer.

[@southerner66]

In the 1930s, The Hammond Organ Company adapted a spring reverb device originally created by Bell Labs and started including them in their speaker cabinets around 1939. These were the large, complicated "oil-tube" reverb units. The driver was basically an 8 Ohm speaker with no cone. The pickup was a piezoelectric crystal. A complex system of springs damped in oil was required to tune the response and make it sound more like natural reverb. (Many no longer work because the crystal pickups fail.) They worked, but people who remember them say they still weren't that great. A man named John Hanert was the real electronics genius at Hammond and helped develop the necklace spring reverb that replaced the older oil-tube system in 1959. Some consider this system the best-sounding spring reverb, but it was easy to "crash" and was still too large for guitar amps. About a year later, Hammond introduced the now-standard spring reverb tank. I've heard that the first guitar amp with spring reverb was an Ampeg Reverberocket, not a Fender amp. Hammond eventually spun spring reverb tank production off as Gibbs, which later became Accutronics. This is why no guitar amps had reverb in the 1950s. Spring reverb existed, but it was impractical to use a 3-4 foot tall unit filled with oil in a guitar amp.

[@Bobby-Love]

There's a good number of amp repair channels on youtube. We all know Uncle Doug and his knowledge base. BUT....In this video you captured the Queen Of Amp Repair position. Thank you for explaining reverbs, its inception, possible reverb tank issues and not talking over our heads. So far one of your best videos! And of course being a pretty lady repair person sure does help. Thanks for your work bringing these videos to us!

[@paulh6591]

In the early 1980s I had a beat-up, transistorized Peavey Standard power transistor amp in which was an O.C. Electronics reberb tank. There was a foil sticker on it which claimed that it was ""Manufactured By Beautiful Girls in Milton, Wisconsin under controlled atmosphere conditions". Has anyone else had this aural pleasure?

[@Murgoh]

I have one of those, I think it's from an Italian 70's EKO organ I took apart.

[@RandalSmith]

I worked with a steel guitar player named Don Saxton back in the mid sixties. The reverb in his Sho-Bud amp died one night and we pulled it out to try and fix it. It had that foil sticker. We had a good laugh about it.😊

[@defaultuser1447]

The Steel Guitar Forum has a post with a snap one of those labels. I will put a link in a separate comment, because sometimes comments with them get nuked as spam. So if you don't see it, you can probably easily find it with a search.

[@reggiewallace260]

I have a 1980 Music Man 112-RD65 with the same brand of reverb. Worked okay but didn't have anything like that lush Fender like reverb. At some point I got frustrated with it and had it replaced with an Accutronics reverb tank which was MUCH better. The OC ended up in the amp in the sky.

[@reggiewallace260]

Back in 1969, I owned a 1965 Chevrolet Impala with a stock Delco AM radio. At that time, a local AM radio station was making a move to the FM band and was selling listeners an FM converter for a very low price. You hooked that up by daisy chaining it between the cars radio antenna and the radio's antenna input. Then you set the radio to a specific AM frequency, then tuned your FM converter to the FM station you wanted to receive. At the same time, I also installed a reverb which I picked up at a local Lafayette Radio. A small amount of reverb went a low way to expand the sound. As I recall the front speaker was left dry and reverb was applied to a rear speaker. This was supposed to produce a "concert hall" effect. At the time I was just 17 and it all just seemed so cool at the time. Thanks Coleen, for the memory.

[@FlipDahlenburg]

And it WAS cool, and still is.

[@shorerocks]

Wow.

[@shader26]

Thanks for that! I repair electronics, make pedals, etc. and went to school for electronics but never delved into reverb tanks (except to troubleshoot and it was always the cables…usually dirt making bad connections) and always meant to because it seemed odd that springs would make reverb. But your clear explanation made it all make sense to me now. My first real amp, in the 70’s was an Ampeg VT-40 and it had a little lever on the reverb tank for transport. I think it just tensioned, or else dampened, the springs so they didn’t rattle. Anyway, thanks, I’m glad I saw this video!

[@scottbenson6348]

Dad worked for Accutronics, their main product in the 70's was reverbs. I worked shipping and receiving one summer and packed up and shipped a LOT of tank reverbs. Good memories!

[@timmotel5804]

Good Day. Very Good. I remember Reverb units for car radios, a million years ago. I had forgotten about them. I bought a 65' Reissue Super Reverb a year ago. Always wanted one. Thank You & Best Regards. i just subscribed.

[@Finom1]

Coleen, it's so therapeutic listening to you. Leaning from you is a true pleasure, thank you so much for sharing, I have learned so much:)

[@lionscircle4700]

I was recommending one of Gerald Weber's books today when I heard he just passed away. There are just so few people that can pass the torch down to eager learners. There are a couple books that can help me out but I can see that the training wheels must come off and I just need to put in the time. It not a job, but it's to breathe new life into old small amps. thanks for the videos.

[@R_Rod]

Love the '65 Silvertone 1482! Have one myself and it's my #1

[@rafaelgonzalez-rb8yq]

I GOT ONE

[@goodun2974]

The input transducer is kind of like a speaker which vibrates the springs in accordance with the music, and the output transducer is more like a guitar pick up which senses the vibrations of these strings and generates a corresponding electrical signal

[@krissxfaded]

I happen to look this up at a good time , thanks for the useful video ! Others I came across didn’t explain it as well as you did . Bless

[@Finom1]

Bless you Coleen for sharing your wisdom and all the valuable history with us in every one of your educational videos.

[@ix-Xafra]

This vid made me think of standing on top of my Super Reverb playing Wipeout and Surfin USA back in da 70s...

[@csumme7]

Interesting video. I had a Princeton Reverb 2 (around 81-82 era) and it had a tank. Crank it just until breakup and roll the reverb to 3 and it sounded awesome.

[@Buffrt66]

I changed the reverb tank in my Marshall Valvestate AVT50. I went with one that had a deeper and longer sound.

[@ambroselockerman1115]

You should check out the reverb setup on hammond tone cabinets. They started out as big necklaces that were not even enclosed.

[@jordangibson695]

One of my favorite reverb tanks are the vintage OC Electronics "folded line" tanks. The reason I like them is that they provide a more "room like" reverb with a wider sweep of usable sound. Larger reverb tanks with more springs seem to go from "nothing" to "Grand Canyon" from 2 to 4 on the dial. The sound of those tanks seems to be more tinny and artificial and less "room like"

[@tonybmusic1166]

I have a Fender Blues Junior that I use quite a bit in my work as a guitarist in the orchestra pit for Broadway musicals and the reverb died on it. Since I depend on the reverb so much I had to switch it out with my Marshall amp which is a bit heavier. I had already tried by replacing the tubes….the reverb tank is next. Thanks for the info.

[@goodun2974]

The output side of the reverb tank should typically be oriented as far away from the power transformer as possible otherwise it may pick up hum that gets amplified and fed to the speaker.

[@boppin_bennie]

Had a spring detach at one end & was able to reattach it (forget if I soldered it or what) and it worked fine, still working.

[@Lily-oz2dq]

Great info. Thank you for sharing Hank with us he looks like a great dog.

[@hearpalhere]

I love a nice subtle reverb. The reverb in the Silvertone 1484 was really crazy... still loveable in certain situations but anything but subtle. My friends and I described it as a garbage can reverb. I loved that amp haha. Thanks for a fun video, learned a few new things!

[@timmotel5804]

I remember Silvertone Amps.

[@wayne00k]

that was an awsome tutorial - thank you! after years of just mic on my acoustics I'm starting to explore electric - glad I found your channel :)

[@curtpozzi5527]

I worked on only one car that had a reverb on AM radio. It was on a 1967 Pontiac Gran Prix convertible...with a 4 speed! That car had a 428 V-8 with these rare 8 lug wheels. It was the only year for the Gran Prix to offer a rag top, let alone a 4 speed. One of like less than 500 of the 1500 sold that year.

[@timmotel5804]

One of my many favourite cars. A friend's dad had a 1963 Grand Prix and his mom had a 1962 Ventura. Great Cars & Great times for cars. Music & Reverb TOooooo

[@ColKorn1965]

Yessss. A memory from my Fender Twin Reverb☺

[@hadleymanmusic]

i love spring. municiple auditorium ( louisiana hayride) had a giant plate with magnetic transducers you could change the time by distance placement

[@pistachioaudiophile]

I just worked on a 74 fender twin reverb where the combined tremolo/reverb wire had a bad connection. Since these wires carry signal before multiple amplification stages, any wear on them can cause huge noise issues like super loud pops and crackles! Just thought I'd share!

[@morolo6665]

Gracias por esta información, es muy difícil encontrarla en algún otro lado. Se agradece mucho que compartas con nosotros tus conocimientos. Thank You !!!

[@AnyoneSeenMikeHunt]

“arriba, arriba … andale, andale”

[@JubileeValence]

In the 1970 I found a used blond Fender reverb head/unit $60. Pure reverb and you could tap on it for springy effects. Now regarding plate reverb, I've only found it in digital recording units. One is worldly. The other is heavenly. Cheers! ----------- Edit: But I've seen huge plate units in my research, but they're room sized things of beauty with the price of a decent car lol

[@jerryhatrick5860]

I miss that sears amp I had one of those. Given to me long before I knew how to work on electronics. I pulled all the tubes de oxed everything g cleaned the tube socket reassembled and it worked perfect and total Srv tone cranked. The speaker was still good as well. But I changed the speaker it was twice as loud. Sold it with the original speaker it's insane what they are worth now.

[@thirstin_more6429]

Great video! Very informative and I loved all the historical tidbits. do you ever get vintage Orange amplifiers in your shop? would love to see you work on one!

[@ARNYKATZ]

I have a Hammond B3 and Leslie 900 cabinet that were given to me a few years back by some folks who had left them both on their back porch for about 10 years. Almost miraculously, they are both almost fully operational...now. The B3 is incredibly over-engineered, so I credit Lorenz Hammond for the resurrection. The only thing that isn't working is the reverb tank. The organ was a touring instrument and somewhere down the road, the reverb half-moon switch was removed. I poked around the Amp in the Leslie and found that the little lights in the photoresistors were broken. I replaced them and tried a few things (including switching out the tank with one from another Ha.mond), but still no reverb. I've been looking for the actual switch, but it's a real unicorn. Anyway, that's my story and I'm stuck with it. Thanks for the primer on reverb tanks.

[@wilhelmvonn9619]

Hope you succeed in bringing the reverb back to life - essential on a Hammond!

[@REDMAN298]

My step dad bought a new `63 Bonneville convertible and it had a reverb. Sometimes it woulf echo from going over a bump in the road.

[@bitwise2832]

Cool video. I have a 1970s Yamaha Hundred 410 and the reverb sounds great. The amp has a very clean sound, but the overdrive is muddy. Such is solid state.

[@trevorgwelch7412]

My 1965 Fender Deluxe Reverb amp has a tube reverb ---- Where does the " tone " of an amp come from . ? Thank You .

[@rstuartcpa]

I had a Danelectro DM-25 with the funky little reverb tank. It was a box which measured one inch by one inch by about nine inches and had the most bizarre sounds.

[@trentc7329]

Great video. Learned a lot. I have to say that you have the most soothing voice. You could narrate meditation videos.

[@fadofasol2254]

Thanks for this video. I'm wondering about the tension running thru such a reverb tank ?

[@DjTroublemaker]

How can I check if the reverb transformer has died? I have tried new tubes and cables as well as a different tank on my Super Six

[@lostreb]

Having been here well over 3/4 of a century now, I well remember adding reverb to radios...Obviously, long before there was stereo. I digress...My question is, is there a preference between the tanks being held in by Velcro or screwed in? I noticed the insulation around the tank, and that, to me, seems like it might be a positive. I totally understand everything with the concept of keeping everything as original as possible when you are working on old amplifiers. My question about "preferred" method of attachment is more "if" there is no consideration for keeping things original (I'm a firm believer in keeping things as original as possible, but I know there are those that aren't that concerned about keeping everything original), or, even more applicable, in new construction. I'm really asking so those that have forgotten more than I'll ever hope to know can give me some insight. Great Video, Colleen...I can't believe I just now saw this tonight.

[@toddhinkle4674]

Thanks for the video. This should help me fix the tank in my Hammond.

[@alexdeleon7135]

Lesson and a show. Thank you for posting, Colleen.

[@niteshades_promise]

i miss my old Traynor pa mixer with a reverb tank. you could hit and shake for that awesome thunderous effect. 🍻

[@6NoDo]

This is the first time I’ve noticed your Peavey tattoo!! Amazing!

[@george-st-george]

Thanks for this !!! great information !!! Tons of reverb... always a great idea !!!!!!!!

[@ge0fthomas906]

Great informative video! I must have missed your video on "how the heck does a vacuum tube work", ...oh well. RIP Dick Dale🔊🎸

[@calsurflance5598]

Dick was a friend for many years. He bought an airplane from where I worked at the Fresno Airport. We sat in his living room, swapped Strats and jammed. I still have mine that he signed and played. He had been screwed over many times by people in the music business and didn’t trust very many people. I am honored he called me his friend. RIP Dick Dale.

[@timmotel5804]

@@calsurflance5598 Always loved Dick Dale. I finally got to see him play at a Blues Club in Phoenix Arizona, about a year before the world lost him.

[@NicArpMusicator]

This is an excellent video. Thanks!

[@r.stanley1049]

Back in the 1960’s, Motorola marketed an aftermarket kit… a rear speaker and a reverb unit, along with under-dash control box for cars with a single front speaker monaural radio. It was called a Vibrasonic… I had one in my ‘66 Ford Fairlane. (Another car I should never have sold!)

[@spinospinellibass]

Cool video! You enumerated several things that could be bad in the reverb tank and the associated circuitry. How do you discriminate and decide which one is actually defective?

[@howardkanitz4998]

That's very cool. Thanks for sharing your knowledge!

[@Theactivepsychos]

I wanna see the springs when the signal hits them!

[@roscius6204]

I've always wondered if a reverb circuit could be repurposed, as say a boost or an EQ. I've had a JCM900 since the 90's 👍 but never liked the reverb, a Bigsky gets the job done these days. Seems like I have 2 wasted circuit opportunities. I'd like to be able to voice the 2 channels differently at the amp.

[@stevenwillett3037]

Brilliant video. Thanks... 😊

[@bob_mosavo]

Thanks 👍

[@nikitamesmaeker4577]

Great tutorial, I just have one more question: When you turn the reverb knob to have more or less reverb, what does it actually do in the reverb tank itself? It sends more or less of the dry signal into the transducer? Or it has action on the springs? Or the receiving transducer? Basically, how is this thing made to not be a "on/off" device 😅

[@wilhelmvonn9619]

It no doubt varies with different amplifiers, but a popular method is to run the signal from the receiving transducer through an amplifying stage and then to a volume control labelled 'Reverb'. This varies how much reverb signal is added to the main signal path through the amp.

[@gustavorb92]

awesome explanation!

[@radioseppe]

I have some random fender sunn o))) sr-30c amp and I opened, cleaned and check everything thru. I took the reverb box out replaced old cardboard bottom with softer rubbery/foamy piece and now I can’t go beyond 3/10 with the reverb knob. Starts feeding back really easily. guess something to do with the more cushiony bottomplate? Never had that problem with cardboard. How about plywood or basic sheetmetal?

[@jerryhatrick5860]

Could we have a viddy on difference between long and short tank reverb units? What happens if I was to replace a short tank with a long tank? Will it work and change the reverb? I bought a reverb pedal to get around it all. But it isn't the same as the real thing.

[@peterburi2727]

I still have an original Hammond-Gibbs tank laying around. The first iteration as far as I know.

[@horizontalblanking]

Hammond borrowed the tech from Bell Labs who used it for simulation of long distance calls in their labs. A missed opportunity for Bell Labs, and shows the genius of Hammond.

[@Les537]

My Vox AC15 suffered a failed RCA to the reverb tank. It's hard to understand how an RCA can just fail, but it was a super low quality cable on an otherwise well built amp. (first year of korg vox).

[@Earthshaker1965]

Excellent video.... Very informative.

[@middle_pickup]

I have been wondering about the different spring circuits out there. How does the reverb in a twin compare to what's in a two rock or rumble with the independent send and return controls for the reverb?

[@JRP3music]

Is there a way to utilize a spring reverb tank in an amp to be used externally placed in post. My noise gate kills my spring reverb in my Mesa Nomad 100. I use a reactive load. Drive my fx from the output of that. I want to place it where my stereo fx chain begins. I use stereo Two Notes Torpedo Cab M IR boxes to send to PA and stereo power section.

[@TheMorphicResident]

Great videos and perfect timing….my deluxe reverb ish amp seems to have intermittent reverb issues where the reverb becomes very weak. I’d replaced the driver with a solid Philips JAN tube and even swapped out the return tube which all helped last time but isn’t this time . Did the cables once too. Any ideas?? Maybe needs to visit the tech 😢

[@75YBA]

Always a great video Colleen! 👍

[@jcwm01]

I assume the the tank is in parallel with the dry signal? Great vid. Cheers!

[@goodun2974]

Yes, and there are "mixing" resistors in the circuit where the wet and dry signals are combined.

[@BluesJammer69]

Ha ha ha...i did ride and a friend's car ...and he had the reverb on the radio...it did sound cool...back in the 70's!

[@goodun2974]

My brother had a 1960's Plymouth convertible which had a factory-original spring reverb tank mounted in the back, for the rear speaker.

[@willliasm]

Thanks, explained

[@ExAstris]

This was great. I hope you do more

[@Dawg93]

I've got a VHT D-50, no on board reverb. How much of an undertaking would it be have a tech make it so I could plug a spring reverb in and control the volume of it?

[@michaelyolch79]

Fascinating! Keep 'em coming! :)

[@TheAmiciNoctis]

Hi! I've been watching your videos from the beginning and you are amazing! Congratulations on your work! 🎉🎉🎉 Could you give me a hand? I have a Vox PF15r and the reverb works at high volume... What could I do to fix it? 😢

[@KeritechElectronics]

Nice reverb tank cover there - should do a nice job protecting against dust and feedback from the speaker. Most of the time I saw tanks screwed to the bottom of an amp using rubber grommets as dampeners. Never heard about reverb in car stereos. That'd be utterly impractical if done with a spring reverb, shock and vibration would definitely break the listening experience if not the tank itself.

[@goodun2974]

My brother had a 1960's Plymouth convertible with a factory-original spring reverb tank mounted in the trunk and wired to the rear speaker! The solid-state factory radio was AM only and so we pulled it out and put an AM-FM radio in there and tossed out the reverb tank.

[@KeritechElectronics]

@@goodun2974 interesting! Always good to learn new things. Especially about how it was done across the big pond.

[@goodun2974]

@@KeritechElectronics , America has always done some weird things electrically and electronically, such as allowing the sale of transformerless, "AC-DC", "widowmaker" radios and amplifiers. Were those ever allowed in Europe or the UK? We tend to be slow to adopt safety codes in general, and in particular if we didn't think of it first! (NIH syndrome, aka Not Invented Here). It's worth noting that some locales still had DC power piped into their homes until the 1950's when everything finally got converted to AC (Tesla eventually won out over Edison).

[@KeritechElectronics]

@@goodun2974 transformerless radios and TVs were a big thing here, especially in the late '40s / early '50s when the country wasn't fully electrified and some places used DC, others AC, 127 or 220V. It was standardized to 220V 50Hz in the '50s/60s as the country was being massively electrified. Before that happened, battery tube radios were sometimes used. Later on, it was just cheaper to make TVs with P tubes (300mA serial heating) that didn't require bulky mains transformers. I guess it was not just a case of Poland, but Europe in general. Post-WWII years were a wild period all over the place.

[@goodun2974]

@@KeritechElectronics, Look Mum No Computer did a video a few years ago where he experimented with a weird *mechanical" reverb device that had no input or output transducers, just a bunch of springs mounted above a speaker, which vibrated along with the frequencies produced by the speaker, generating pronounced resonant effects at various frequencies. Sweeping sine waves and tones through it created some incredible sound effects.

[@digitalranger4259]

So on an amp like the Princeton, technically, isn't the reverb in and out an effects loop?

[@micahwatz1148]

My crate gt1200h only makes reverb when i bang the tank. I checked the tank with a multimeter and its good. No clue what i need to do.

[@johndoe-ep7qk]

never in my life have i heard a young woman talk about spring reverb, or any other amp minutiae 🤩 liked and subscribed

[@nilsgrafo5999]

Thanx for another good video! How could one make an effects loop out of a send/return for spring reverb? What would you have to do with the resistance and the voltage to make it work?

[@eDoc2020]

AFAIK the input of the tank is a low-power 4 ohm load. On the 65 reissue schematic it's fed with 1.1v. So you probably need something like a small headphone amplifier. The output of the tank is listed as 1.9mv on the same schematic so you probably need a signal amplifier to boost it to more manageable levels.

[@MusicalBox]

Thanks!

[@bluedot6933]

I have a accutronics. when I put it on 5 and above I start to get some hum in the amp. would another tank fix this?

[@JohnAdams-or9xw]

Love your videos thanks for sharing.

[@lisaayers1975]

Thanks 👍 Could you do one on the Tremolo or Vibrato..I know I was freaking out when I could see a pulsating orange looking light from the back of my Fender Quad Reverb Amp..Found it it was some kind of oscillator with a light I think..I have seen that replacement part on ebay before..❤

[@tri00azerath]

That's just one way to create that effect, there's others as well!

[@KeritechElectronics]

That's how they did it: a low frequency oscillator driving a neon lamp placed in front of a light dependent resistor (a.k.a. LDR or photoresistor) which modulated the audio signal or output tube bias voltage. There was a Polish guitar amp made by Unitra Fonica, model W701, which used an EM84 magic eye tube as a light source in the tremolo oscillator, coupled with a big RPP131 photoresistor. The tube was covered with a special shield with a round hole drilled in its side, where a LDR was placed. Pretty uncommon - I'm not sure if any Western company did it this way.

[@goodun2974]

​@@KeritechElectronics, none that I'm aware of. Not to mention that European style eye tubes were and are expensive here in the US, but neon balls are cheap. This also begs the question, which device turns on and off faster, a neon bulb oor an eye tube? I would think the "persistence" of an eye tube would be less desirable for this type of circuit.

[@KeritechElectronics]

@@goodun2974 it depends on the phosphor's glow time and neon's ionization time; both certainly affect the characteristics and differ from those slow incandescent bulbs. Magic eye tubes can be pretty fast, but probably slower than neon lamps - which have ionization times in range of tens or hundreds of microseconds, allowing kilohertz frequencies.

[@sesa2984]

Did any amps ever employ plate reverb? If so, I’d love a demonstration of whatever the heck that is.

[@sesa2984]

Looked it up. THAT WOULD BE A BIG AMP. But I’m in!

[@JB4848-xl7qw]

Where can I find just the springs that are used in a tank?

[@dave.harmon]

So I'm assuming it would take a lot of work to fit a reverb tank to an amp that didn't have one fitted from the factory.

[@alanpecherer5705]

If you copied a typical Fender, it would take at least one tube and more likely two tubes. A driver, and a recovery tube. It would not be Nobel-prize electronics engineering, but finding the physical space to mount the tubes could be tricky, and you can't always predict whether shoving more electronics in a fixed space with high-gain elements in there will not cause noise or feedback. In a Fender, I think half of one of the tubes is unused if my memory is correct which it isn't always.

[@FuriousMess]

Lol about the car reverb. I have an old Ampeg V3 combo I sold to a friend years ago and bought back several years later. His little brother removed the reverb tank out of it to put it in his car and lost it. How do I figure out what tank would be a good replacement?

[@goodun2974]

Ampeg and Magnatone used capacitor-driven reverb circuits and the tank that works in a Fender will not work in an Ampeg (wrong input impedance). I've seen a chart online somewhere that explains the numbering code on the tanks and tells you which one to use for Ampeg as opposed to Fender.

[@alanpecherer5705]

Google "Accutronics reverb tank codes" and hopefully you can get a part number by googling "Ampeg G-3 schematic". Some tanks are meant to be mounted vertically, some horizontally. The codes specify which. You'll still have to buy the bag if the amp has one, but fortunately, reverb cans themselves are pretty cheap.

[@Kuztomshop]

Crazy question: can I add another reverb tank, in series, to the one that's already in my amp? Basically piggyback two in one amp.

[@alanpecherer5705]

You could do that, but I'd bet that it would cost you a ton of gain. It won't blow anything up.

[@jjbba]

Tanks for that, Colleen :B

[@davidethridge5748]

How serendipitous! I was just messing around yesterday with the reverb tank in my Peavey eCoustic 112. It makes a slight hum when I turn the reverb up past noon, could you tell me what that might be from?

[@eDoc2020]

I'd guess it's magnetic pickup from the power transformer.

[@davidethridge5748]

@@eDoc2020 what would dampen that?

[@eDoc2020]

@@davidethridge5748 Exotic materials like mu-metal could help. But the easiest thing to try is to take the reverb unit out of the cabinet and rotate it 180 degrees.

[@davidethridge5748]

@@eDoc2020 it goes away when I touch the metal on the rca cable input or output on the reverb tank, when I took it out I realized.

[@eDoc2020]

@@davidethridge5748 That makes sense. I think one of the RCA jacks on the tank (I forget which) is probably supposed to connect to the tank's case and this connection might be bad. Or maybe the RCA cable is slightly damaged.

[@zacharykelly4088]

Really interesting, great video!

[@geronimostade8279]

I am a metallian... I mean serious ... metallian. We metallians hate reverb... so its been said. I am possibly the only metallian on earth who acutually loves real spring reverb. There is no build of mine where i havent had thought of praising the spring lord and giving it a tank aswell. And Fazio, you probably hear this alot... But i do adore your channel! It feels so good knowing, that the repair business is not only fitted by big belly and bearded guys. I wish you all the best and the success of your channel is well deserved by fundamental knowledge, experience and attention to detail. I call you mate! But i wonder why we were not quite yet able to just marry. 😂 Just kidding! God, whoever he is may bless all your doings.

[@rrobb786]

Is it possible to fix a spring that broke off at the connection near the transducer? I've got an original Gibbs tank from a blackface Deluxe Reverb that I'd really love to get fixed so it's original with the amp.

[@alanpecherer5705]

There are about 3 ways to fix a broken tank. 1: Resolder the wires at the input/output jacks. 2: resolder the wires on to the transducers. Delicate soldering required. Many times they can fixed, but you're dealing with very small wires so your soldering technique has to be good. I have on very few occasions been able to resolder the single heavyish wire that comes out of the center of the transducer, but that's very hit and miss. Put it this way, if the thing is truly broken, you don't have much to lose giving it a try. Reverb cans are actually pretty cheap if you need to replace it. Make sure you get the right part, google "accutronics reverb tank codes".

[@NebulaStudios1]

You get a $2,000 amp and the reverb tank has a two-bit piece of cardboard attached to it. What other materials could be used?

[@uphillracer]

Thanks, that was really interesting