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Discussion in 'Glowing Bottle Tube Amp Forum' started by Wharfcreek, Sep 13, 2019.
Try a ceramic speaker
That’s what I’m using now. Jensen C8R in one Nd Warehouse G8C in the other. Hence my ordering a couple of Alnico types
The biasing of the output tube is very important on a single ended amp. The window for the sweet spot is very narrow. Might have an effect on compression.
Wobbles, very true! However, the rules go out the window with Guitar amps as to 'bias' level. I say this as referenced to what the tube manufacturers recommend for biasing as opposed to where guitar amp designers and 'tweakers' put the bias. As an example, if you go to a tube data chart for an EL84 / 6BQ5 tube, the recommended level for plate voltage and bias when running 'Cathode Bias' Class A is all based on tube AC swing. In other words, the tube is producing an AC voltage swing from positive to negative, and the tube data charts are to allow a designer to know where the tube goes into a 'clip' ...... so that can be avoided. It's probably true to say that the design intent of most of these tubes was NOT to be run into an over-driven situation such as in a guitar amp. On the contrary, most tubes were designed to simply amplify a voltage, and do so WITHOUT distortion. Then, along came the electric guitar, and things changed. I don't know who gets credit for being the first to go from 'clean' to 'distorted' ...... maybe Les Paul himself. But, in reality, most 'early' guitar amps were not designed to distort......or to distort very little and only at high volume levels. But, again, it was those 'high volume levels' that became the icon of early rock music, not to mention producing a major change in the approach of 'blues' players. Anyway, unfortunately there's no 'tube data' for finding a proper bias level on a cathode bias guitar amp, nor a 'fixed' bias amp as far as I can tell. It all becomes a function of how the original designer of the amp decided the tube was to be run, and then how the amp owner decided what changes were to be made.....if any. The same somewhat applies to plate and screen voltages. And if you get really curious, you can take a look at some of the signal tubes like the venerable 12AX7! What some guitar amps do to that tube in terms of voltage overload and signal distortion......this makes some 'Hi Fi' guys cringe. There are some guitar amps that will literally EAT the tubes up......and after a year or so of limited use, they become so weak it's time for replacement. For some performing bands, replacement is a nightly thing. This is fine if you're using currently available tube like those from JJ, Electro Harmonix, or some of the Asian tubes now available (which are getting pretty good!!). But, if using old US stock or some of the Euro production tube like Amperex, Telefunkin, or others.....that's a very poor use of otherwise very valuable and irreplaceable tubes. Not that most guitar players really give a flying-frog! But, it would be nice if they did. I could go on a real rant about this one, but I"ll just quit now and say 'thanks' for the comment on bias. It's something that took on a life of it's own in the guitar amp world!!
Guitar amps that "eat tubes up" are the exception. They're not common. The ones that "eat tubes" came along in or after the "everything louder than everything else" era of the late '60s.
Most vintage amps are easy on tubes. For example NOS tubes last decades in old Fenders.
Didja know Fender stuck Telefunken 12AX7s is just about everything in 1965? Even Champs and Vibro Champs?
Musicians ask me,
"Why don't you design your amps for new production tubes?"
as if new tubes are something special. Fact is any amp designed within parameters gleaned from tube data sheets will make any tubes last longer.
Now the bad news: Tube manufacturers have no incentive to build better tubes. Quite the opposite. If they can sell you tubes that are adequate when they're new, if they can sell you tubes that last long enough that you lose the receipt and / or forget where you got 'em… they're all set.
A properly maintained mid- '60s Fender amp re- tubed with NOS will run for decades relatively trouble free just like it did when it was new.
Same amp with new production tubes... re- tube it at least once a year if you rely on it to earn your living.
My champ clone is rather dull. People say they should sound good at about 4 on the dial. Mine doesn't even click on until about 3. If I play at 4 or 5 or even 6, it's quiet and dull sounding. No overdrive at all until it's nearly maxed out. Thinking about doing that input cap mod thing but the problem is that I just called it the input cap mod thing. Meaning, I have no idea what to do or how to do it.
Gobi, you may be suffering somewhat from the same impressions of the amp that I am. Fortunately for me, I have a fair amount of experience with amps in general. However, this said, each amp can have a personality of it's own, much like a guitar though people often fail to consider this. Recently a friend of mine when shopping for an SG. He said he played over 100 of them until he found the one he liked. These were virtually all SG Standards, new production, and essentially all the same guitar....even the same wine red color. But, as stated, they all had slight variances that made the decision to buy one rather difficult for my friend. In my Hi Fi world, I can line up a dozen Scott 299D amps, and I can guarantee you that of the 12, one or two will sound 'stellar', and one or two will sound 'not so good'. The remaining eight or ten will be acceptable.....just not 'great'. I'm pretty sure it's the same with guitar amps, and perhaps the fact that this little Champ amp is so simple, it makes it all that much more evident when things just don't come together well. Granted, if everything is to spec, it will work pretty much as per the original design intent. But, as one of my other friends puts it, there will be 'that one!' that just has that MoJo......and makes you say: "Why can't mine sound like that one?". And, there-in lies the struggle. Again, same with the guitars. We re-carve necks, change pickups, put wood in kilns to 'cure' it, and now even put it in 'tumblers' (as if that REALLY makes a difference?)....and play with finish coatings.....blah, blah, blah! All to make a 'new' 2019 Strat sound like a '57.....or what-ever!
MuchXS..... I presume that 'XS' is meant to mean 'excess', yes? I happen to own a small fleet (7) of Yamaha's old XS 650 motorcycles......so my first reaction to your XS was to think of the bikes. You being a good 'Brit', you'll also perhaps appreciate my love of old Brit Bikes, and I'm a former owner of probably 20 old 'vintage' Triumphs, Nortons, Royal Enfields, and a few others. I currently own a 'new' Triumph 'Scrambler' which sits aside my '01, '04, and '19 Harley Davidson bikes and a few of those XS650s. I've had a few Brit autos as well, and recently sold off my old MGB. I miss that car! Miss my old '68 XKE even more!!
XS, I appreciate your taking the time to respond in all this.....and I can tell you're a knowledgeable guy. I can also tell that, like most Brits I've met, you're pretty set in your opinions. I did NOT know that Fender stuck Telefunkins in all their '65 amps! However, comes as no real surprise. Back in '65 I think the tube plants in GB and Germany were operating at about the height of their production? I don't know where things were here in the US..... but I do know that the bottom was getting ready to fall out of the 'tube' market! With the advent of the Transistor....I think that pretty much put the knife into the heart of the Tube business back then. I think by about '70 or so, Tube production here in the US wall all but done! I imagine it was pretty much the same there across the pond. Anyway, hopefully you'll agree with this: There are a LOT of 'variables' when dealing with the concept of 'tone'......and with all the different speakers, cabinet designs and materials and covering methods, tube types, not to mention 'modifications' that are available.....making changes to an amp like a Champ is almost a world of possibilities in and of itself. I can only imagine what people go through with something more complex, like a Marshall or old Black Face Fender amp. But, my point is: There are really no rules.....other than those that might apply to 'safety'....and even some of those get broken, particularly in the 'chassis ground' area. So, when speaking about things like the Epiphone amp..... I give the designers and builder some latitude. And, if the amp sounds 'good' in terms of tone and volume when done.....then who's to say that the design is flawed?.....you???? I don't think so! It's different, it's unconventional, and it may 'appear' to be 'flawed' as related to general considerations. But, again, if something like that amp can work as well as it does, sound as good as it does, and even be 'available' as readily as it is.....then I would be rather cautious with my criticisms lest I be perceived as being 'closed minded'. Hopefully I've made my point here.
So, this thread as well as what I've found on the internet has given me a LOT to consider to 'modify' my little Champ and make it more to my liking. And, I stress that one point: MORE TO MY LIKING! I'm going to give it a rest for a bit, wait for the couple of speakers I've ordered to arrive, and when they do, I'm going to play 'speaker swap' for a bit and see what affect that has before I go changing things too much within the amp circuit itself. And, I may also build yet another 'mule' amp on just a chassis....just to play with the circuit there before I go into the ones in the cabinets. But, Thanks to all! for the contributions.....and I'll give an update to my 'speaker games' in another week or two after they all get here and I have some time to draw some conclusions.
New England <> England. New England is one of the former colonies of Left Pondia. Not a Brit.
Add some bright caps on a rotary selector. I mistakenly referred to the bright cap as a bypass cap earlier. My bad.
1uF/10uF/22uF 25V bypass to V1a, consider the same to V1b ( not counting any rectifier valves in the numbering )
Use a basic Shuguang 12AX7. They are bright and fizzy compared to 60's - 80's production Brit/Euro/Japanese/American valves ( to my ears ). I find JJ to sound rather dull in mine, but Sovtek and old production as listed above work just fine.
Double check the bias. Get it running hot.
Listen to some recordings made with Champs.
Each to their own. While, to steal a phrase and mangle it, you'll prise my Champ-a-like from my cold, dead hands, they may just not float your boat.
ps. The XS 650 needs the Westlake 840 conversion.
OOOooooppppps!! Here I thought he resided across the pond! You two guys neighbors?
So what is the Westlake 840 conversion? I'm aware of Hugh's re-phase motors....which I think he runs at 750 cc's. But, an 850? That would start to rival my old Commando but with a 5th gear! Honestly, I don't think the crankcase components could take that kind of increase in power. They're already running on the ragged edge if you ask me, particularly the clutch. About every XS I ever run into either has a bad clutch or a recently replaced one.
I WILL try some of the V1A/B bypass mods you're talking about. As to 'floating my boat' (which is a subject near and dear to me since I live 'on the water' and go fishing nearly every day between the first of March and the end of December!!)..... here's my 'take' on that: As I said, I've 'cloned' this amp a half a dozen times, each time being somewhat different from the last. I basically started by buying the clone 'kit' amp that Antique Electronic Supply (AES) sells...... the MOD-102+ version. That started a chain of events that had me building a couple more from 'scratch' using up some of the parts I had around here. I should probably post a pic or two. Anyway, each one is 'different' in that I changed rectifiers, output tubes, power transformers, output transformers, added a choke, and changed layouts.....but essentially I followed either the 5F1 circuit, or I did 2 of the 5E2 Princeton builds....just to see if the tone control really did anything for me. After build the MOD kit and the first 3 clones I decided to buy a chassis, a turret board, and a proper Champ enclosure.....and build a 'replica' amp....which I did.....all 100% to 'spec' (if there is one). I then did one more 'clone'...then I just decided to buy the complete Kit version from MoJoTone! Somewhere in there I also did a complete re-build on an old Gibson G5A amp...the little Les Paul Jr amp. I'd been given an 'original' version of this amp some years back.....and it was basically 'junk'.....so I did pretty much a ground-up overhaul on it.....all new amp parts, new OT, new speaker baffle and speaker, power cord, cab back. About the only things left 'original' is the cab itself, the chassis, the PT, the tube sockets, the power switch and the pilot light! That was fun!
Anyway, I ended up selling the MOD-102+......but I still have all the clones and the two 'replica' amps, as well as the Gibson. The point here is that in 'cloning' this amp as I have, I've pretty much proven to myself that the amp CAN sound GREAT to my ears......and honestly to those of others who have played my clones. This said, I will say that of my 4 clones, 2 sound really good to me, and the other two, not as much. However, ALL of them sound better than the two 'replica' amps. So, I don't know if the fact that I'm using other speakers, have 'altered' the circuit some, or just what is the difference. BUT, I DO know that it CAN be done! So...... just a matter of 'how' and 'when' for me. BTW, I might add here that the MoJoTone Kit is supplied with a slightly larger cabinet than the one I purchased through the Reverb vendor. I dare say the first one is probably the 'correct' size as it just looks like it to me. It was also covered then 'sealed' and looks great! Just not sure how that sealer is affecting 'tone'. I has the Jenson C8R in it. The MoJo Kit amp, being slightly larger, I believe was made this size to accommodate MoJo's attempt to 'up-sell' the buyer with a 10" baffle board and speaker. My amp currently has the Warehouse G8C in it. I think I'm going to fabricate my own baffle board and do a 10" conversion to that cabinet, as I think the Alnico 10" speaker I have in one of the other cabs is perhaps my best sounding unit. We'll see. I still have three 8" alnico speakers coming my way, all paper cone 'vintage' types, though one is I believe one of Ted Weber's newer speakers (from 2005 or so).
So.........that's my wrap up: I content with where I am....but I want to make it be what I believe it can be. And, when I do, I believe this will also make it more to the general liking of most of the other friends and players that I know, as we all tend to agree on the 'tone' of these things as they are now. So, time will tell. Again, thanks to all for the comments and contributions!!
Finally; my apologies to XS for the error in location assumption! I love the north-east! If I didn't hate winter so much I'd move to New Hampshire in a heart beat!
Like Marshall Lead 12s, I'd have a difficult time sayin' how many XS650s I have at the moment. Here goes:
In chronological order,
XS1 basketcase, non- numbers match although it's 100% XS1. Main frame is around SN670.
Numbers match XS1
Numbers match XS1B formerly owned by the mechanic at the local dealer. That one has almost 100,000 miles on it and it's never been apart. Can't tell for sure 'cuz the original speedo exploded around 30,000 miles ago.
Numbers match XS2, the pretty red one. Motor is out of that one and leaned up in the corner.
Numbers match '73 TX650. That one is in big chunks and scruffy.
I built up another very early XS1 for my former riding buddy. That one was built into a chopper before XS650 choppers became the rage. I built it up like an old dirt track bike so it was kind of a street tracker / chopper juxtaposition. It could fool just about anyone into believing it was some previously unseen and über rare chopped Brit when it was going down the road. That one incorporated
Plymouth ('39 Plymouth tail light)
Subaru (frame hacked by previous owner plugged with balls from Subaru CV joints)
McCormick- Deering baler
I had a small herd of '74, '75 and '76 TX650s that gradually went down the road to feed the XS650 chopper fad. In retrospect selling some dumb- ass a running bike he's going to convert into a debris field makes me a dumb ass.
Got another '74 parts bike out in the barn.
Got a '76 out in the garage.
Got my '79 gently rusting in the other garage.
If you think I have a lot of bikes bear in mind I hocked a bunch of them, bought amp parts and then proceeded to virtually give the resulting amps away.
I have half a dozen T100s, at least four TR6s not including two or three Bonneville basketcases.
My '51 Thunderbird went into the back of a rented mini- van in big chunks. I converted it into a thin wedge of cash and... guess what? I bought amp parts.
I still had the complete front end of my '69 Trident. Guy who bought my Trident was going to race it. He was making noises like, "Ceriani, Fontana, Grimeca, Water Buffalo, Buchanan's" so I kept the front end. Turns out the Brit who bought my Thunderbird also bought my old Trident down in Pennsylvania. Cliff bought it from the guy who bought it from me. It's all in a sea container headed back to Merry Olde England right now.
I'm pretty sure I'm all done riding. I don't bounce as good as I used to. I certainly don't want to do a Stephen Hawking impersonation in the time I have left. I'm not worried about my riding skill. Half as good as I used to be is still twice as good as some of the jokers I see on the street. I'm worried about Grandma. Grandma can't see me. She can't hear me. Grandma will leave tire tracks across my corpse and remain blissfully oblivious to my existence.
Most of the bikes are going away. Buddy of mine is going to show up with his dually and his 20' toy hauler within the next week or so.
I'm gonna buy me some amp parts if I have a few coins left over.
Valve Junior versions one and two were junk, are junk and always will be junk.
When you're talking about "rules" bear in mind electronics obey the laws of physics. Disobey the laws of physics at your own peril.
There are conventions of amp design that display massive feng shui while others display blissful ignorance of anything resembling style and grace.
When we're talking rules... we all obey more or less similar rules of Grandma Avoidance when we ride. See above.
Too bad you're not closer; I'd probably try to snag a deal or two from you.
I can tell you this: What ever we may differ on regarding the amp stuff, I COMPLETELY agree with you on the 'grandma' comment! And, I'll go a step further and toss in the cell-phone crowd! I ended up in the ER 2 years ago when a woman ran a red light and I T-boned her at an intersection. Thankfully I was in my Jeep at the time.....and at the expense of it's life, mine was saved. But, had I been on the bike, I'd be taking a dirt bath right now.....or more likely my ashes would be crab food in the Chesapeake Bay! A couple weeks ago I took a trip on my new '19 Street Glide. Rode from here outside of Baltimore up to Niagara Falls, then on to Detroit, then Upper Michigan...then back home. Sadly, 4 days of 'rain riding', which didn't make me happy! But, in going through Cleveland up by the Lake Front, damn near in front of the Rock & Roll Hall of Fame, and still in the rain, some guy decided to make one of those urgent lane changes across 4 lanes to move from the far right to the far left side so HE could make his left-side exit. Of course, while he cutting across, I was in his path. I literally slammed the hood of his car with my right hand and damn near bought the farm in, of all places, Cleveland. Could have gone to visit the 28 club members!....lol Anyway, I'm 67, and it was only the fact that I've been riding since I was 12 and I ride like I'm invisible......I'm ALWAYS expecting the worst, and this time when it happened I was somewhat ready. I survived it......but.....Yea....it scared the hell out of me.....as well as ROYALLY pissed me off!!
We'll have to compare notes on the XS stuff some time. I have a 750 Street Tracker out in my garage, but it's sick and needs some kind of help! Doesn't run worth a crap and I was told by a guy that claimed he once worked on the bike that he though it had a cam problem....like a press-on gear cam where it might be off one spline or something. He claimed he took the bike into his shop and found the pistons were installed backwards so he reversed 'em and reassembled the engine. He said it didn't run worth a crap then and the owner just took it away. I doubt it saw daylight again until I bought it.
Anyway...... I'd love to get a running T100 again. I love that little bike!!! One of the best 'riding' bikes I ever had. Of course, that was probably 40 years and maybe 90 pounds ago........lol
My pile is going most of the way to Maryland. Looks like it's going to end up in Delaware. Can't tell you for sure until it happens.
Guy told me T100s aren't worth a (poo) cash- wise. O.k.. Fine. If my über scruffy '72 isn't worth a damn I'll just keep it. And my '67 scrambler. That one is ugly right now. It won't take a whole lot to make it pretty again.
The previous owner of my '67 tore the motor completely apart. He parts out T100s and assembles close ratio gearsets for vintage racers.
I have a '72 Daytona motor leaning up against the wall in the garage. That one has the better head and the bearing on the timing side rather than a bushing.
Seems to me the sensible thing to do is run it non- umbers match. Can't blow a hole in the numbers match cases when they're in a milk crate under the bench.
So if I understand you correctly, you DO have a 'salvageable' 500, yes? I'd be interested in that if your deal with your other guy falls through. I made the trip to up-state NY to bring home a Royal Enfield some years back......and I drove all the way to Florida to buy an eng/trans for my MGB. Some times half the fun is the trip to go get the stuff!! Anyway....good luck with your sale......and if you end up with a 500 or even a non-OIF 650, I'd be interested. Thanks, Tom D.
First time I have felt bad for only having a ZX14r ninja-but I did have a XS750 once upon a time!
I have a friend with one of those. Actually, we met when he purchased my '01 Harley Dyna Super Glide Sport back in 2015. He too was a 'crotch rocket' kind of guy and was buying the HD because his wife saw my ad for it and thought it looked kinda cool. He's a rather 'well to do' type.....own's the top of a mountain out west. He sent one of his planes to pick it up and fly it back to his house. I thought he might ride it a few times and be rather 'stuck in his old ways. However, I guess all the work I'd done on that bike paid off for him, as he pretty much abandoned his Ninja and became a HD 'convert'. For 2 years he sent me pictures and videos, even tried to get me to meet him in Sturgis for the bike rally out there. I have to say that this particular HD was kind of a freak, and performed much like a Ducati on steroids. I miss that bike!
I rode for 30 years year round with no car in central illinois-so I might be a biker! I have had every make over the years-and love them all. The xs750 I spoke of I gave a friend for christmas and he still rides it to this day. Even a honda elite scooter is better in the winter than a car if you have to ride. Its like being a musician- the worst job in the world if you want to do it- the best job in the world if you Have to do it! Thats how bikes are with me!
Is there any MGB owner, ever, who hasn’t said that?
On a 5F1, my filter cap lineup is 33-22-10 F&T's. NFB should be 33-39k I think with an 8 ohm speaker to match 4ohm levels, but I like it with 56k at 8ohms. Almost gets a 5e3 feel. V1 bypass at 5uf or less if you really like to play cranked and/or hot pickups.
This 5f2a with that lineup was through a 1058 Legend. Brighter speakers help a lot.
Listen to 5f2 - Tele by Jason White on #SoundCloud
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