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Post by morbe on Dec 31, 2011 9:45:39 GMT -5
Hello everyone I was looking at second hand vintage guitar store and saw a 1981 Fender Super Reverb. The owner wants $599.00 for it and wont budge on the price. First off it has scratchy pots and needs a good cleaning. The tube may need a swap as it sounds a little off. The speakers are obviously the orignal and I was afraid to crank it because of the old speakers. Cosmetically its a nightmare. Two tears in the grill cloth no longer than a couple of inches. The Tolex is completely worn off on the corners exposing the wood that is now starting to become frayed. a couple of control knobs are broken, but there. In my opinion it needs A LOT of TLC right away! at the very least new tubes and new speakers and new pots. I have completed extensive research. Ebay has the same amp in better shape for this exact same price. To my Novice knowledge of this particular amp the 60's models are the prize and go for well over $1000.00 and the price just seems to go down in the 70's and just really drop in the late 70's and 80's. Should I Pester this owner on letting it go for less? Or just move on? I know the mans gotta eat but Damn! I just want to tell the owner, "Why don't you get out from behind the counter and lets take a look at it together and talk about price." but He just doesn't want to budge. What should I do?
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Post by ijustwannastrat on Dec 31, 2011 12:16:28 GMT -5
Do you love it? What's it worth to you?
Finally, cash may be your friend. It is less expensive for store owners to deal with cash, if you catch my drift. Also, I would point out these flaws. Yes, you understand that that model goes for $xxxx, but because of the damage that requires fixing you would like to drop $100, or whatever it is.
You're correct, the guy needs to eat. But I'm sure he's selling this amp above his real bottom line.
Also, if you do buy it, we need some pics.
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Post by cynical1 on Dec 31, 2011 13:33:14 GMT -5
This is a real can of worms you opened here...
Unless this shop is busy constantly, there's probably a good time to drop in with your guitar, and a few pedals if they're part of your regular rig, and test this bad boy out. Obviously, during a busy Saturday is not your best option, but a quick quiz of the owner should give you a window.
Granted, you're not dropping several thousand on this amp, but it is used, of questionable virtue and from what you describe may very well have fallen off a bus on the way to the store.
You don't have to go to concert level volume, but you want to see what it does in the store before you get it home. Plan on spending 30 minutes with it getting to know it and putting it through its paces and waiting to see what happens when it heats up.
The last thing you want to do is develop an emotional attachment to it before you get a chance to see if it works.
The owner really shouldn't object if you do this on a slow day or evening. If he does balk at this request, then move on. If he's afraid you'll blow the amp under acceptable volumes and stress, then move on.
There's a reason these amps go for high dollars in workable condition. Repair costs and labor can add up quickly on these amps, and by the time you're done fixing this one you may very possibly exceed the cost of a verified working amp with new tubes...
And cash on the spot can be a motivator. Just remember he knows his market better than you do. If there is a counter offer accepted it may very well come with an "AS IS" condition, as well as a "NO RETURN" proviso. If he stands firm and won't budge then he's probably certain some sucker will come along and take it off his hands for his price.
You can also request that a third party qualified amp tech look it over, at your expense, and if it passes, then go for it. If it fails, mention the proposed costs of repair or recondition. The Tolex and grill work is something you can do for under $50.00. The speaker(s), tubes and guts can add up quickly. You seem to have a good idea of what reconditioned sells for, so base your offer on initial purchase cost and repairs, then see how that compares to a reconditioned amp. If it falls in line pull the trigger. If it exceeds what you can buy a reconditioned amp for, them move on.
Happy Trails
Cynical One
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Post by newey on Dec 31, 2011 15:17:40 GMT -5
In the other thread, reTrEaD noted: Added to the $600 price, you're at $1350 if those numbers are accurate- and I think they're maybe a bit high but not by much. Of course, as cyn1 noted , you can DIY the grill and tolex and save a bit. But then, of course, you have to do the work. And, in the end, it's still a 1981 Super Reverb, not the most desirable era for those beasts. Bear in mind that a brand-new 1965 RI Super Reverb runs $1500. Comes with a factory warranty, too. That extra $150 might be money well spent. And, it's a replica of what is considered the best SR circuitry. Granted, it's a RI, but it may be better than the original from a reliability standpoint.
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Post by morbe on Jan 1, 2012 9:02:22 GMT -5
Yeah, i dunno, i'm a do it your self kind of person. Because who is going to give your stuff the special attention it needs other than you self. i can swap out pots no problem. I know a guy who deals with speakers and has all the vintage speakers reconned and restore the grill cloth. ready to go not to mention he will most likely buy the old speakers to restore them. Im pretty possitive i can re-tolex the and an clean up the fraying wood. I guess what im trying to say is that. I would like to restore the amp to as mint condition as i can. But thats a long run and time down the road. Oh but i forgot to mention the amp is listed $699 regular price and $599 sale price. As far as i know he doesnt have an amp tech on site. Just a guitar tech. not sure he would let the amp leave the store to have a tech look at it with some kind of. deposit
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Post by cynical1 on Jan 1, 2012 11:56:41 GMT -5
According to Fender, "the legendary Blackface™ Super Reverb® of 1963-1968 is a must-have for vintage enthusiasts". Maybe they'll come out with a 1981 Re-issue one day...but it's been over 30 years and I don't see one on the horizon... And a little research into the 1981 Blackface amp reveals it's just a Silverface amp with a cosmetic panel change...which has a different transformer & Et cetera then the original Blackface amps...if that matters to you...
Let's be practical for a bit here.
$599.00 + tax put you in over $600.00 for a 30+ year old amp of less then thoroughbred stock.
You buy 4 pots and pay shipping...$30.00
Let's say you get a deal on the re-coning and it only runs you $125.00
The Tolex and grill cloth is an easy $50.00...maybe $100.00 if you go first class.
I'll go with the $200.00 for new tubes and biasing...which is reasonable.
Minimum you'll have $405.00 to $455.00 into this amp...along with your labor and gas to run it around. Now, lets say there are unknown issues with the internals...the tally just climbs accordingly.
So, at $1005.00 on the low end to $1055.00 on the lucky high end you've got an amp that works...provided there are no issues with the guts. If anything major goes on this thing within 30 days you could be out a few hundred dollars more.
All this for an amp that has a market value of around $650.00-$850.00 in good working condition.
Well, I talked myself out of it...
As newey pointed out, the Fender Re-Issues are around $1500.00...with a warranty. A good original Super Reverb can be had for around $1700.00-1900.00 if you look and remain diligent in your search.
If you're good with your hands and like to DIY, a Blackface kit runs anywhere between $650.00 to $1000.00...and you don't have to clean spider spore out of the cabinet...
I always recite the first rule of Salesmanship whenever I go into a store to buy anything. "A good salesman will always make you want the thing more then you want the money that it takes to buy the thing." In this case, it's more money then it's worth in the condition that it's in...especially without the sign off of a qualified amp tech. I nosed around a bit this morning and found that beater 1980's Fender Blackface amps generally go for around $200.00 to $300.00 in pawnshops all day every day.
I'm not trying to be cruel or condescending. For that kind of money for an amp in that condition you're just going to lose your shirt on it. I don't think anyone here will tell you that you're getting a bargain on this amp. Good intentions aside, for $1000.00 there are some nice amps out there to be had that only require you to plug them in to use them.
If your heart is set on a vintage Super Reverb, then save up another 6-12 months and buy the real deal. Buy it right, buy it once.
Happy Trails
Cynical One
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Post by reTrEaD on Jan 1, 2012 14:34:33 GMT -5
not sure he would let the amp leave the store to have a tech look at it with some kind of. deposit Unless you have a long history with this store, I'd be surprised if he let you leave the store without the full price of the amp as the "deposit". Look at it from his point of view. Would you allow someone to walk away your amp? A close friend, sure. But someone who is basically a stranger, no way. There's nothing to keep him from leaving his "deposit", never to be seen or heard from again. To recover your amp, you're the one who will now have to pursue the (costly) legal work. Better to never put yourself in that position in the first place. Yeah, i dunno, i'm a do it your self kind of person. Because who is going to give your stuff the special attention it needs other than you self. i can swap out pots no problem. I know a guy who deals with speakers and has all the vintage speakers reconned and restore the grill cloth. ready to go not to mention he will most likely buy the old speakers to restore them. Im pretty possitive i can re-tolex the and an clean up the fraying wood. The tolex work might seem easy, but it isn't. Not unless you have several jobs as experience. Getting period-correct tolex shouldn't be too hard for a Fender. But if you go cheap for something that sort of looks like the real thing, it will always sort of look like the real thing. Expect the first tolex job you do to have a lot of waste and take about 10 times as long as you estimate. That way you'll be allowing yourself enough time to get it right. Speaking of time ... DIY work is all well and good. You can learn as you go along. But that requires a moderate investment in money and a huge investment in time. Not a problem if you have a dependable amp right now and are doing something like this as a project. But if you're looking at this as being your main amplifier, each time you do something to improve it, you take it offline until that phase of the restoration is completed. This becomes a major (dis)incentive. You may find yourself procrastinating to the point where the amp never sees any of the work you originally planned. I guess what im trying to say is that. I would like to restore the amp to as mint condition as i can. But thats a long run and time down the road. Okay. Until that happens, will you be satisfied with the amp as-is? I always recite the first rule of Salesmanship whenever I go into a store to buy anything. "A good salesman will always make you want the thing more then you want the money that it takes to buy the thing." In this case, it's more money then it's worth in the condition that it's in...especially without the sign off of a qualified amp tech. That's one of the attractions of an old amp in rough condition. The buyer tends to think of what the amp could be, without a full appreciation of the time and money it will take to get it there.
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Post by morbe on Jan 3, 2012 0:24:40 GMT -5
You know what?! I hope you guys don't think I'm a Retard but I purchased that Super reverb!!!! Please don't crucify me, I'm a tone junkie and need help! Don't worry, I have some to play on in the mean time. Till I can get it looked at. I've been playing it for a while. You know I went back to the store 3 times today to look at amps. I did have my heart set on a Twin Reverb Reissue. I tested the TRRI and it sounded nice, real nice. Then I went back to take another look at the Super reverb and the longer I looked at it, and thought its 30 years old and it still fires up! That more than I can say about my HRD! In that same store I also tried out a Fender Custom Vibrolux Reverb reissue and then back to the Super reverb. Then I went home and thought about it. All I could remember about it was the sweet tone it had compared to the Custom Vibrolux reverb. This is my "57 Chevy" per say. After I sell my HRD I'm going to use that cash to begin restoring this amp. I really don't care about time and money not on this amp.
So after thinking about it for a while and weighing the good and the bad and potential. I decided to talk with the owner "I knew I was going to pay his asking price when i went back to the store. But we looked at it and I talked with him and we played it and we went back and forth. so finally I he took off 50 buck big deal somethings better than nothing.
I love the Tone!!!!!!Crisp crystal breaking Highs and nice lows. Playing all the reissues. It was as if they were build by simple man, but this Amp was created by Gods. I can't explain it for some reason in the cosmos I was drawn to this amp and I know that's a bit corny and cliche.
Oh and the owner did claim that it was looked over by a tech to make sure it didn't have any major issues. But I do have some questions since I'm new to older amps.
1. Can I assume that because I plugged it in and didn't get shocked while playing that its safe around all other high voltage gear? for instance I don't want to call it a life because I eat the mic when I sing.
2. I was given a pedal but with the pedal only reverb works. not tremolo, but if I swap the cables on the pedal then I get Tremolo not Reverb. Don't matter I just use reverb any way, I have a tremolo pedal.
3. is it normal to have an audible "A#" hum from the amp. I checked to make sure it wasnt the Transformers that where humming, and its not vibrating and the hum gets covered up by the ground noise of a stratocaster's single coil hum. The "humming noise" seems to come from the speakers.
4. when the Reverb is activated by switch I get a louder hum that does increase with the volume, the hum is very similar to what a high gain amp would sound like. For instance when I engage the switch it's sounds like I just hit a distortion pedal on high gain.
Thats it for now I recorded some things but I dont have time to uploaded them right now.
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Post by morbe on Jan 3, 2012 0:34:07 GMT -5
Oh and my wife asks, "Dear God How do you get that smell out of it?"
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Post by cynical1 on Jan 3, 2012 0:38:14 GMT -5
HTC1
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Post by morbe on Jan 3, 2012 1:03:27 GMT -5
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Post by morbe on Jan 3, 2012 1:05:47 GMT -5
HTC1 awe c'mon you guys already gonna start giving me a hard time?
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Post by sumgai on Jan 3, 2012 1:41:02 GMT -5
morbe,
If'n yer happy, then we're cool too. ;D
I've more for you later, but it's late and I need to do some valid work at ODarkHundred, so hang tight......
sumgai
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Post by reTrEaD on Jan 3, 2012 2:04:44 GMT -5
You know what?! I hope you guys don't think I'm a Retard but I purchased that Super reverb!!!! Please don't crucify me, I'm a tone junkie and need help! It was a decision I had hoped to discourage you from, but what's done is done. Crucifying you won't make things better. I sincerely hope that you have the minimum of grief from here on, but I'd be lying if I said I feel this is likely. I did have my heart set on a Twin Reverb Reissue. I tested the TRRI and it sounded nice, real nice. Then I went back to take another look at the Super reverb and the longer I looked at it, and thought its 30 years old and it still fires up! That more than I can say about my HRD! Comparing this to an amp that has been a nightmare for you is an easy hurdle to clear. Yes this amp is 30 years old and is (at the moment) working. But how many times has this one been repaired. You simply can't know. It might have never been opened or it might be a complete butcher job inside. All I could remember about it was the sweet tone it had compared to the Custom Vibrolux reverb. The Super has 4-10s. This is one of the most important factors in its unique tone, compared to similar Fender amps. I wonder if you had the opportunity to play a SRRI, perhaps you would have felt the same way about it. I can't explain it for some reason in the cosmos I was drawn to this amp and I know that's a bit corny and cliche. It's natural to feel elated after a purchase. Especially so when buying something that's less common. You probably felt quite good about your HRD when you first bought it. Let's hope this turns out much better in the long run. 1. Can I assume that because I plugged it in and didn't get shocked while playing that its safe around all other high voltage gear? for instance I don't want to call it a life because I eat the mic when I sing. No, you can't assume that at all. I don't know when Fender stopped installing the ground switch with the "death capacitor", but I know it was still there in the earlier silverface years. Job one will be to get a proper 3 prong line cord installed on this amp, if that hasn't already been done. If you've ever experienced the "Fender kiss", you'll know this is extremely unpleasant. 3. is it normal to have an audible "A#" hum from the amp. I checked to make sure it wasnt the Transformers that where humming, and its not vibrating and the hum gets covered up by the ground noise of a stratocaster's single coil hum. The "humming noise" seems to come from the speakers. 60 or 120Hz is slightly sharp from an A#, slightly flat from a B. If it sounds a little "buzzy" rather than a smooth hum, it's probably 120Hz from poor filtering on the HV supply. 4. when the Reverb is activated by switch I get a louder hum that does increase with the volume, the hum is very similar to what a high gain amp would sound like. For instance when I engage the switch it's sounds like I just hit a distortion pedal on high gain. Fender amps of that era had the switching accomplished by shunting the signal to ground, at the footswitch. Unplugging the footswitch should allow you to use the reverb with less hum. Oh and my wife asks, "Dear God How do you get that smell out of it?" Resist any temptation you may have to look at her and say "I could ask you the same question." Trust me, that won't end well.
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Post by newey on Jan 3, 2012 5:58:27 GMT -5
As RT notes, question #1 is whether it has a three-pronged cord or not. If not, that's job 1 on your restoration- and to be done before any gigging with this amp!.
But tube amps can still fail and put voltage through to your guitar. For complete safety, get a wireless system.
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Post by lpf3 on Jan 3, 2012 6:34:43 GMT -5
Congrats on the purchase & happy new amp day. As RT notes, question #1 is whether it has a three-pronged cord or not. If not, that's job 1 on your restoration- and to be done before any gigging with this amp!. But tube amps can still fail and put voltage through to your guitar. For complete safety, get a wireless system. I agree, make safety your first priority- I got a "little" bite while working on my Twin, and wow, I'd hate to get the full dose. Looks like your amp has earned it's scars honestly & you've got a tone monster on your hands. Personally I didn't mind the look of the Tolex as much as the grill cloth - but either way you'll probably enjoy the DIY project. And if you do have any repair issues down the road, at least you're in the right place. Enjoy..... BTW- I clicked thru your pics and got to the toy train set- talk about a trip back to happier times......... -lpf3
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Post by morbe on Jan 3, 2012 10:00:19 GMT -5
Well thanks for not candy coating things guys. I am full aware of what may come from this project. I do have an other amp that i plan to make my main amp. I used to have 1951 chevy that was a project of mine. So i really know what im headed for. I can honestly say that at least i have a plan. I didnt buy think thinking it was going to be my main amp right out of the shop. I still do appriciate every ones opinion. I will keep you guys informed as to my progress and will humbley admit i was head over hills but will also love to hear a year down the road that i got lucky it it was a decent find. It does have a 3prong chord. And i do plan to take the amp to a good shop and say, "please look this over and lets overhaul it if needed. " And i know that there are some that will say that the money i spend i could get a nicer more quality amp, and your all true. But i wil recite the famous scene from "la bamba" where ritchie jams with his band for the first time. And the band leader tells ritchie that his amp was a piece of junk. And valens replys, "well its mine now".
I guess what im trying to say is that i respect every ones opinion here, and i hope you dont think ill of me when i ask for advice. And come on dish it i have thick skin and can take it. Lol i really do enjoy keeping you guys up to date.
Lol about trains, my son and i were making stop motion animation and the photo bucket auto uploads pics,
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Post by reTrEaD on Jan 3, 2012 14:58:00 GMT -5
I guess what im trying to say is that i respect every ones opinion here, and i hope you dont think ill of me when i ask for advice. And come on dish it i have thick skin and can take it. Lol i really do enjoy keeping you guys up to date. I can only speak for myself regarding whether anyone thinks ill of you. A lot of advice was offered but in the end it seems you made more of an emotion decision, rather than an analytical one. But that's the nature of advice, isn't it? You give information and opinions, but in the end the person making the decision is the one who has to live with what comes after, good or bad. None of this causes me to think ill of you. It certainly has me scratching my head, but it hasn't cost me anything. So yeah, keep us up to date as events unfold. Since this already has a 3 wire line cord, job one will be to get the stink off, so it's less offensive to your wife. From the looks of the grille cloth, I'd guess cigarette smoke and spilt beer. Try a product called "Simple Green". It's an enzyme based cleaner with a pleasant scent. Spray it on the tolex and wipe it off with a clean cloth. You can use it on the grille cloth, but don't spray it directly at the speakers. Spray it diagonally across the face of the grill. You won't be able to wipe the grille cloth effectively. But that's not really important. You just want to get a mist of the product on the cloth. Not to clean it, but to mask the smell.
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Post by cynical1 on Jan 3, 2012 15:14:37 GMT -5
Odo-Ban is another real good odor removal product. I smoke like Pittsburgh back in the 60's, and this removed the smoke smell in two different houses so we could actually sell them.
And I don't think ill of you. It's your $600.00...plus whatever the final damage runs into...
I'd like to see you get lucky on this one. Who knows, maybe you'll make out on this one.
I've just seen too many people get hosed on old but not valuable amps and guitars in the past that my natural inclination is to toss up the red flag before you shoot yourself in the foot... but hey, it's your foot.
Happy Trails
Cynical One
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Post by newey on Jan 3, 2012 18:30:54 GMT -5
Well, when Cyn starts mixing his metaphors, look out . . . ! ;D ;D
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Post by cynical1 on Jan 3, 2012 18:34:21 GMT -5
My metaphors are the only things speaking to each other around here these days...
HTC1
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Post by KIIMH on Jan 3, 2012 22:12:53 GMT -5
My metaphors are the only things speaking to each other around here these days... HTC1 finelly ... soemone ho "gets" me! kyle
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Post by morbe on Jan 6, 2012 12:27:50 GMT -5
Upate: just got the amp back from an amp tech last night. Over all the amp is in decent shape. Some scratchy pots. There some loose items in the chasis that were tightned up. The amp looks like it had something dropped in it, but luckily it only slighlty damaged the frame and the reverb and tromolo pots. Easy fix to replace a couple of pots. There are no burn scars, burn marks or hot spots in the electrical components. The caps were all original so it was suggested to get them replaced and they are on order and i have an appointment for recapping in a week and a half to two weeks from now. The tubes were an older bottom of the barrel set, though still good they are a little weak when tested but still fine (this amp tech is a bit anal retentive) he said to start looking for low current draw set of power tubes. Because a set i pulled out of an hrd are "to hot" in terms of current draw. But we are going to try again after caps are replaced. The speakers are still in good shape for 31 years of age and was told they still have years left of service. There are a few more little things like needing a new reverb cable, since it was replaced by a non fender non amp part. Over all he said it was a great find. Said the hum could be nothing and shook it off as some old amps just hum. He said i could play through it and encouraged it but since i know it needs caps and power tubes, i can wait. I dont want to get impatient and ruin something. I did have. Few question, i didnt want to sem like a complete idiot though. Will new caps effect tone? And what and where and how do i get low current draw tubes?
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Post by cynical1 on Jan 6, 2012 13:07:14 GMT -5
Hey, I'm just glad to hear this amp has some life left in it. It's so easy to get reamed on these things.
There are others here with much more technical savvy on tube amps then I, but I think preserving the functional integrity of the amp is equally as important as preserving the tonal characteristics of the amp.
You don't want any of that smoke to get out...
Happy Trails
Cynical One
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Post by reTrEaD on Jan 6, 2012 15:36:02 GMT -5
Will new caps effect tone? Depends on which caps we're talking about. Electrolytics in the power supply? No. They only filter out the buzz from the rectified DC. Coupling caps? Yes. Changing the type of cap there could make a subtle or even profound change in tone. Depends on what you have to begin with and what you change to. And what and where and how do i get low current draw tubes? Some vendors offer tubes that are pre-selected based on how much idle current they draw for a given bias voltage. Imho, this is a rather odd way of addressing biasing. Better I think, to adjust the bias to accommodate the tubes you have. The silverface Super doesn't have a real bias adjustment like a blackface. It has a "bias balance" pot. This only allows you to lower the bias voltage on one tube or the other to get the idle currents equal to each other. It would be a good idea to have your amp tech modify the circuit. Either add a pot so you can adjust the overall bias voltage, or change the circuit to match the blackface design. While he's at it, it would be very simple and useful to insert 1 ohm resistors in the connection between cathode and ground, for your output tubes. This will allow him to measure the bias current by measuring the voltage drop across the resistors.
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Post by morbe on Jan 7, 2012 16:19:11 GMT -5
Some vendors offer tubes that are pre-selected based on how much idle current they draw for a given bias voltage. Imho, this is a rather odd way of addressing biasing. Better I think, to adjust the bias to accommodate the tubes you have. The silverface Super doesn't have a real bias adjustment like a blackface. It has a "bias balance" pot. This only allows you to lower the bias voltage on one tube or the other to get the idle currents equal to each other. It would be a good idea to have your amp tech modify the circuit. Either add a pot so you can adjust the overall bias voltage, or change the circuit to match the blackface design. While he's at it, it would be very simple and useful to insert 1 ohm resistors in the connection between cathode and ground, for your output tubes. This will allow him to measure the bias current by measuring the voltage drop across the resistors. The Tubes that I had at idol tested in the safe range but high enough that if they if I played the amp hard they would peak over what they are rated for. And I take a change causing the tubes to burn up. And that Since I had no way of testing these on my own if wanted to buy new tubes it was a safe bet to put in low gain tubes. I did confront him on putting Bias Pots on the amp and he said sure said he could even put a pot on each tube and teach me how to bias each of them so It wouldnt matter if I put matched or unmatched tubes in it. His only disclaimer was that I would loose tone and the amp would not be as warm. I still would like a bias pot to take out the guessing game for me since Im going to be the one to bias the tubes after he's done with it. Also making it a black face was the first thing he mentioned to me. He said that it could be done, the room was there for the circuitry and rectifier tube, but that It was going to cost a bit for parts since I would need to get a 40 watt transformer and that my amp would no longer be 70 watts.
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Post by reTrEaD on Jan 7, 2012 20:36:37 GMT -5
The Tubes that I had at idol tested in the safe range but high enough that if they if I played the amp hard they would peak over what they are rated for. And I take a change causing the tubes to burn up. And that Since I had no way of testing these on my own if wanted to buy new tubes it was a safe bet to put in low gain tubes. Actually a tube that has a lower plate current for a given bias will have a higher transconductance (higher gain). But that isn't terribly important. The largest factor affecting the maximum power that can be dissipated is the amount of (magnetic) energy stored in the output transformer. That's determined by the idle current. Higher transconductance just means that less drive from the phase inverter is needed to get you there. The basic rule of thumb here is to set the idle current to allow 70% of the tube's rated plate dissipation power at idle. I did confront him on putting Bias Pots on the amp and he said sure said he could even put a pot on each tube and teach me how to bias each of them so It wouldnt matter if I put matched or unmatched tubes in it. His only disclaimer was that I would loose tone and the amp would not be as warm. I still would like a bias pot to take out the guessing game for me since Im going to be the one to bias the tubes after he's done with it. It seems the easiest way to have individual bias adjustment would be to simply replace the 33k resistor in the bias network with a 25K pot and a 22k resistor in series. The new pot sets the overall bias and the existing pot allows you to balance between tubes. I don't recommend using tubes that are highly mis-matched, but even matched tubes aren't perfect. The "tone loss" from mis-matched tubes will be more even ordered harmonics. Not a horrible thing, but odd ordered harmonics are the signature sound of an overdriven push-pull output stage. Also making it a black face was the first thing he mentioned to me. He said that it could be done, the room was there for the circuitry and rectifier tube, but that It was going to cost a bit for parts since I would need to get a 40 watt transformer and that my amp would no longer be 70 watts. Dear Lord, no. I hope you didn't misinterpret my mention of the blackface's bias circuit, as meaning I thought you should turn the entire amp into a blackface. That would be a very bad idea.
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Post by morbe on Jan 8, 2012 6:45:20 GMT -5
The basic rule of thumb here is to set the idle current to allow 70% of the tube's rated plate dissipation power at idle. This is exactly what he said and the tubes that I tried were hotter that 70%. and its not like we tried set after set after set. The reason why told me lower gain power tubes is because he thought that I was just going to blindly buy power tubes plug them in and start playing with checking them. I guess right now power tubes were not his main concern only the fact that the resistors were 31 years old and was very highly suggested they be replaced before it became a main gigging amp. I don't recommend using tubes that are highly mis-matched, but even matched tubes aren't perfect. The "tone loss" from mis-matched tubes will be more even ordered harmonics. Not a horrible thing, but odd ordered harmonics are the signature sound of an overdriven push-pull output stage. Ohh Please forgive me, I think that this comment was misinterpreted. Frank (who I took it to) didn't mean that he really wanted to add two separate Bias Pots so I could actually put in an unmatched set. I think his point was that once he start adding circuitry to the amp I take a chance that tone will be lost. I'm still getting (one) bias pot installed. Its seems to be the consensus that its worth the little tonal loss if any. The good from having a bias pot modded into amp far out weighs the bad from tone loss. but of course that all depends on who you talk to. Dear Lord, no. I hope you didn't misinterpret my mention of the blackface's bias circuit, as meaning I thought you should turn the entire amp into a blackface. That would be a very bad idea. No I didn't misinterpret you comment at all. That was just what Frank told me right off the bat. First thing he mentioned was that because the amp chassis was similar to the black face template it in fact did have all the "cut out and saved space" (if you will) to easily convert it. I guess he was a bit excited to see the amp and was hoping to sell a back face mod job. But he's cool real down to earth kind of guy he didn't push it in any way, but he did make it known that it was a possible options. He knows I'm a restorer and not a modder.
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Post by morbe on Jan 8, 2012 7:01:40 GMT -5
By the way I know its hard to tell but, on the lighter no technical side of things I was at a near by fabric store Hancock's (hee hee) Because on the phone they claim to have a pretty decent vinyl section. And can you believe that they had Tolex! Its not actual "Fender Tolex" sold on line for $25 a yard but matching Tolex non the less. They had the exact match of black tolex for $12 a yard! Then I tried to bargain with the lady saying "C'mon discount it a bit, how often do you sell this?" come to find out its a hot!! item there. But she pointed me to remnant area where they had odds and ends of it. I found a perfect 3 yard piece of it for $5 dollars a yard. a $15 dollar piece.....But its not true black. its had a silver hue, I'm assuming its suppose to look aged? buy I want to buy the true black tolex vinyl but I like the price of this one and thought what you guys thought about the "off" color.
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Post by newey on Jan 8, 2012 7:23:03 GMT -5
morbe-
If you were planning on restoring this to absolutely original condition, then the answer would be "no", but you're planning on using this, not selling it down the road to some collector.
You're already modding the bias circuit, and as was said earlier, an '81 will probably never have much "vintage value" anyway.
So, I'd say go for it, with one proviso: Make absolutely sure the piece is big enough to do the whole amp. Since it's a remnant, if it turns out to be a bit shy of the size needed, you may not be able to match the piece easily- and your bargain evaporates.
I have no idea whether 3 yards is enough. But measure closely, and be sure to leave some extra for overlapping and wastage.
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