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Last edited by Gris; 03-03-2009 at 02:40 PM.
I put the chassis in the cab to see if it made any difference and I snaped a couple of shots.
Last edited by wingnut1; 03-03-2009 at 06:00 PM.
Outstanding!
That caused me a little double-take! Looks a lot like something I got sitting in my living room with a CV Tele plugged into it. Great job!.......Bill
What!? A cheap guitar into a great amp??? That's blasphemy!Originally Posted by cwilliamrose
I'm a little short of choices, my only other one has a pup problem. Besides, I need to get used to a 25.5" scale length. The frets are pretty far apart by comparison. I have big hands but they aren't as flexible as they were 20 years ago.What!? A cheap guitar into a great amp??? That's blasphemy!
I like the guitar but I have little to compare it to. I bought the Tele after becoming unemployed so I needed to get good value for small money.....Bill
Oh man, I was funning ya. There was a recent long contentious thread about what was more important - the guitar or amp. And I was/am a big proponent of amp over guitar. So, what you got is perfect by me!
I didn't mean to come across too serious Mark, but I really don't have much guitar-wise. Wish I did. I saw that thread but didn't have much to contribute beyond relating a story I was told about Steve Morse wondering around a store playing all sorts of guitars and amps and sounding exactly like himself no matter what he was playing or playing through.
The amp was all luck (thanks Dad!!), this "player" just needs to up his game a bunch to be worthy........Bill
Well, you can always whip out that '66 Stang for the corksniffers. I saw Todd Rundgren make what looked like one of those sound pretty good many years ago.
There have been a few big name players that used a Mustang in years past, including John McLaughlin. There's really nothing wrong with that guitar but because the scale is short, it feels a little cramped width-wise for my hands. It used to feel perfect so maybe my fingers are a bit thicker than they used to be. I thought briefly about installing a neck with a wider nut dimension but didn't do it.
Until the 'Stang gets the pup fixed, a new nut and fret work done, I'll be using the CV. Maybe after that too, I like it well enough to semi-retire the Mustang...............Bill
I tried to use the optional diode bridge rectifier to raise my voltages and see if it increased the volume. It took out my B filter cap so I'm going back to the GZ34 rectifier. I've also ordered a new OT and I'm going with the bigger one. This will give me more flexibility since I'm adding the Vari-Watt FX as well. http://www.skipzcircuits.com/products.html
That amp should scream with a properly functioning 35 watt 125A6A.
Okay this is weird, I replaced the cap with another 16uf 450Volt cap. I moved the red PT primaries back to the tube rectifier socket, put the same rectifier and tubes back in. Now I'm at 463 volts on the plate and 46mA that's right at 70% max plate dissipation and 20 watts per tube. The amp is a little louder and sounds a little better. I also replaced R35 with a 470K ohm resistor and the the Vibrato is much improved. I already ordered the beefier OT so I think I will still install that and the Vari-Watt FX.
That R35 was 1 meg stock?
Yes it was.
So, the 'throb mod' works on the big browns as well - cool.
Yes it does, I wouldn't mind a little more, but it's much improved. I'm still wondering where the extra 30 volts came from? I wonder if the cap that blew was suspect from the start and holding things back? The amp is getting closer to what I envisioned when I started out. I'm going to get an oscilloscope to help me diagnose things faster in the future.
Was it a blue Sprague or a black Weber 'Jap cap?' I kinda need to know as I'm getting ready to build a BFTL and am deciding whether to keep using Spragues or go with the cheapies (still would be double Sprague 80s in first stage no matter what).
Maybe the only difference between yours and my buddy's 'real' '63 is the speakers now. His were louder sounding than yours. I put an Emi Cajun and super loud 10F150T-like old '80s Pyle w/ mucho high end in it.
The 10F150T (or the VERY similar old Pyle) really 'wake up' amps. That's why so many folks like em in Princetons. They make the amp sound twice as loud with all that top end snap.
If you don't use pedals and love the snappy sparkly Fendery verb sound, they rule.
The cap was one of Weber's, but the diode bridge was putting over 480 volts and it was a 450 volt cap. I've never lost one of his caps before, except some 25uf 25 volt caps.
My speakers haven't had time to really break in yet and I'm sure them are going to sound better and better over time.
I find this amp has more midrange and less high end compared to a BF. I also put the bright cap on a slide switch so I can take it out of the circuit if I want.
Yes, that's what I like about it - not as scooped. And you need to crank that tapped treble pot up to make the magic happen. I'm gonna put more mids in my BF Tremolux clone too.
So you really turn up the treble pot? I noticed that the treble pot has the extra tab, other than making it more confusing wiring it into the tone stack, what does the tap do?
Yeah, I run the treble pretty high on my blonde Twin. Funnily enough I crank the bass. I've never done that on an amp before.
Makes it sound chunky but not overpowering.
The tapped tonestack is quite strange and really interactive.
See for yourself! Play with it and find out, LOL. Turn the bass down first, then back up. Try starting with the treble at 12 o'clock both ways.
You've seen the thread on what the insides of Spragues look like, right?
I've been using the Xicon General Purpose electrolytics for years with no problems, and they have the exact same operating specs as Spragues, and are smaller and MUCH cheaper.
Here's the thread
"...pray do not imagine that those who make the noise are the only inhabitants of the field;
that, of course, they are many in number; or that, after all, they are other than the little,
shriveled, meagre, hopping, though loud and troublesome, insects of the hour."
-Edmund Burke
I'm sure that the cap that went was suspect to begin with and I put it over voltage by about 40 volts. I don't have a problem using the caps that Ted supplies. In the 10 amps I've built so far this is the only one that has gone.
Well, Jerry the Geezer just came over with his DRRI and we jammed for a while. The VV sounds good, but at 10 on the dial it wasn't any louder than his DRRI on 5.5 or 6. A 2x6L6 amp should be much louder and have a lot more punch than a 2X6V6 amp. I think the OT must be the issue, I hope the new OT will solve the issue.
The amps has good tone but it should have more volume or he'll be on 10 all the time with no headroom.
Well, that's what I said - Matty's '63 VibVerb w/ orig OT is WAY big-time loud. Sounds 3x as loud as a DR.
I was sick all last week so the amp just sat without being looked at. Since that time I have picked up an oscilloscope and a signal generator to work on troubleshooting. I'm not experienced with these tools so any help will be appreciated. In thinking about the problem I'm not sure that I've described it correctly, I think that I'm getting the proper output from the OT and power tubes. I think that the problem is that the output section isn't getting a strong enough signal from the preamp. This is the same from both the normal and bright channel. Since it's the same from both channels I decided to start trouble shooting where the channels join and feed into the power section. I hooked the oscilloscope to the output jack and the signal generator to one side of c33 the 500pf cap that the two channels feed into. On the one side when I adjust the oscilloscope so that the sign wave is on the screen I get 5 volts on the other side I get .5 mv. I'm thinking that this cap may be attenuating the signal to much. When I get a chance I'll change out the cap and see if it makes a difference.
I finally got the amp to where it needs to be, at least on the bright channel. The amp had too much negative feedback and it was killing all the gain from the amp. I changed it from 4.7k ohms to 47 ohms and now the amp sounds great. I changed the 1 meg resistor that mixes the two channels to 220k ohms and I put a 12AT7 in V6. The Bright channel is now right where I want it I need to make some adjustments to the normal channel to balance them out.
That's interesting, Wingnut. It's known that there's a discrepancy between the 6g16 original layout vs. original schematic on that resistor. The layout calls for a 470ohm, whereas the schematic calls for the 4.7K. Either is in series after a 10K.
I find that odd, because the BF Vibroverb has an 820 ohm and 47ohm in series. Seems like a really big difference between the two models.
I wonder if I goofed here in my BFVV, too? Hmm...
"...pray do not imagine that those who make the noise are the only inhabitants of the field;
that, of course, they are many in number; or that, after all, they are other than the little,
shriveled, meagre, hopping, though loud and troublesome, insects of the hour."
-Edmund Burke
Is there any value to looking at mine? Or maybe the photos already posted show it?? Not that I can read a resistor code or even know which one to look at.........Bill
On the blackface amps there are some different value resistors feeding into those two resistors. I'm not sure that those resistors are really in series since the signal feeds in where they connect to each other and the one controls how much of the signal feeds to ground while the other controls how much negative feedback is applied to the output jack. I was talking to my amptech and he said I could also connect the negative feedback to the 8 ohm instead of the 4 ohm tap and that would make a difference.
William, if you have low output and not enough gain in your amp you might want to play around with this resistor. On the Weber schematic I believe it's R60.
I was thinking visually, bad choice of words, but in my head I follow the wire from the speaker jack to ground, and in between I stumble across the two resistors.
Still, it's good that you've discovered your signal drops.
"...pray do not imagine that those who make the noise are the only inhabitants of the field;
that, of course, they are many in number; or that, after all, they are other than the little,
shriveled, meagre, hopping, though loud and troublesome, insects of the hour."
-Edmund Burke
Oh, I missed this issue while out of town. I'm gonna have to look into it. Just finished the 2x6L6 Gristo Gigmaster last night. It's a screamer, THRICE as loud as a DRRI - even with just a 5U4 in it, feels like 45-50 watts easily. Fixed my oscillation problem. Turned out I had used 50 uf bypass caps throughout instead of 25 uf - DOH! ... :-)
Glad to hear that Gris, I used 25uf/50volt instead of the 25uf/25volt that Weber supplied.
Mine has no output issues unless you count not going above 2.5 for fear of rattling our windows out of their frames. I'll look at the schematic and see if I can find it on the board. The photos I posted are clear enough to read the resistor's values, I'll give it a shot. I don't think it would be wise to "experiment" on my amp anyway.......Bill
Edit: Add photo. Is this it??
Last edited by cwilliamrose; 03-26-2009 at 03:06 PM.
I used a bargain PT that was a tad overpowered. Was over 500v witht he GZ34, down to 475 with the 5U4, LOL! Pretty sweet with an AT7 in the PI and a 5751 in V1. Too beastly with an AX in V1!
Yes William that's it.Mine has no output issues unless you count not going above 2.5 for fear of rattling our windows out of their frames. I'll look at the schematic and see if I can find it on the board. The photos I posted are clear enough to read the resistor's values, I'll give it a shot. I don't think it would be wise to "experiment" on my amp anyway.......Bill
Edit: Add photo. Is this it??
So the Weber layout and schematic are both incorrect. This must have been a problem in the past, I wonder why those two documents haven't been corrected........Bill
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