Rebuild 5w tube amp to drive 2x10 cabinet?

[BooneDog]

I want to get one of the smaller tube amps that I'll use to drive a 2x10 cabinet that I'm building with tweed finish. I've never had a tube amp, and would love to build one, but I think to start, and also just to have a starting point, I'm better off to buy one of the cheaper amps and turn it into a cool little tweed cabinet/head combo.

So I'm thinking of something like the Peavey Valveking 8 (at $99), (or Epi Valve Jr, Fender Champion, etc) stripping all the components out to go into a small custom head cabinet that I'll build to match the speaker cabinet.

So I'd end up with a neat little boutique looking home setup, that I hope would sound pretty decent, will be fun to play and experiment with and I'll have very little money in it.

I know the Valve Jr, or Champion are so popular, but the Peavey, at $99 gives me a headphone jack, gain, master volume and tone controls, hi/lo inputs, really a lot of features. I'll do a 'custom' faceplate and use chicken head knobs, setup where tubes are showing, kind of Vox Nighttrain like.

Of all the forums out there, this is the one where I seem to find the best information, what are you guys thoughts on this? An amp like this running 2x10 cabinet, then I can play with different tubes, and start learning about

I'm not a professional musician, nor even a good amateur for that matter. More of my focus is on improving playing skills than searching for some special tone. This is just for fun and learning.

Any suggestions, recomendations on a starting amp? Since I'm taking the speaker out of the equation with the 2 x 10 (and I may build a 1 x 10 also)
is there any reason the Peavey with it's features isn't a screaming good deal for $99 at Music123?
I actually think it's a rather homely looking, ugly amp, but since I'll be rehousing it, that doesn't matter.
It's an 8 ohm speaker, and my cab is 4 ohm(with 2 x 8 ohm speakers). I suppose there's a way to get around that?



All I have in the house right now are my son's Line 6 15watt, a Vox DA5, Roland Microcube and Acoustic B20 Bass Amp.

[muchxs]

To put it bluntly the Valve Junior is still flawed, even the Mk III version. Why oh why couldn't they just copy a simple vintage amp and get it right?

Champion 600, same lament: Why oh why couldn't they just copy a simple vintage amp and get it right?

Haven't messed with the little Peavey yet. When it comes to little tube amps I build my own, anyway.

I'd still go with the Peavey by default. You could of course go with a Blackheart, spend the extra bucks. It's worth it. By the time you get done screwing around with the Peavey you'll probably have spent as much as a Blackheart. Custom faceplates cost money, too.

Build a 2x10", even if you go with the Peavy stack it on top of your 2x10" and you're done. You then have a choice of a tiny amp you can carry on the subway or a larger cabinet when you need it.

Leo said "We'll make it work really well first. If we have any money left over we'll make it pretty."

Leo was an industrial design genius.

[BooneDog]

Yea, the blackheart looks nice, and I know it's a great amp, but at twice the price... and heck, what would I do to improve it? They are pretty awesome as is I think. If I were looking for a ready to go setup, I'd be looking at that, or probably the larger fender champs or blues jrs. I'm thinking of doing this as opposed to trying to just build an amp from scratch.

I guess similar to taking a cheap guitar and learning by replacing pickups, controls, do a refinish, etc, rather than just trying to do a from scratch build first time around.


I'm just starting on the speaker cabinet, so I'll have some time to play with it with the other small amps I have also. Which will be another cool experiment, the little Vox/Microcube type amps powering that cabinet, then a small 5w tube amp doing the same.

I'll do the faceplate and any fabrication of hard parts like that myself, so that's not a cost issue.
And I don't need to keep the practical combo amp setup for this, it's purely for the fun of doing it. I have both a vox da5 and roland microcube that I can carry anywhere I want. (not that I'll do anything to this setup that I couldn't put back)

Really I'm doing this for the fun of it, to practice building the cabinet, and seeing how these things work. If it were purely, get the best tone, I promise you i'd be buying something already built, and sounding just like I wanted.

And I agree with that Leo quote COMPLETELY, that's the way things should be done, but this is absolute play for me, I'm doing the complete opposite in this particular case, I'm building a very cool looking(pretty) head/cabinet stack, and then I'll play with making it sound good :)

[-Vampyre-]

I think you have a great idea. In the end if the amp doesn't sound up to par, you have a 99$ starting platform for mods.

[muchxs]

Originally Posted by BooneDog

I guess similar to taking a cheap guitar and learning by replacing pickups, controls, do a refinish, etc, rather than just trying to do a from scratch build first time around.

It's different. There's a lot more wiring in a simple amp than there is in a guitar. Peavey doesn't build their stuff to accomodate people tinkering inside it.

A kit build is easier.

[jefrs]

I think the easily modified EVJ is a one-trick pony, I bought mine to experiment on. I have tried the little Peavey, it's a similar idea - 12AX7 + EL84, but it's like one that has been modded, and then put into a box that's too small with a grotty speaker, underwhelmed. A good kiddies bedroom blaster. It wants an 8 ohm load and it doesn't seem to be tapped for anything else, watch that. Head + cab is a good way to go, there are a number of small amp heads out there, but buying cheap is often disappointing, especially if you simply have to buy a better one two months later.

[BooneDog]

Thanks guys. As far as tapping the 8ohm peavey for 4 and/or 16. Can that be done? Or how is that done on the EVJ?

Keep in mind I'm taking it out of the box and running 2x10's. Everyone talks about how loud these 5w tube amps are. I'm not in an apartment where sound is an issue, the only sound police I have to worry about on my 5 acres are my family. Maybe I should be looking at 15w amps?

I also have a few pedals I play with. As far as just starting from scratch, I don't really find anything that looks like it would be under $300 to do that. Then I look at this $99 setup, and figure there must at least $99 of parts just in the chassis, power cord, transformer, knobs, jacks, switches, tubes and misc bits and pieces that I could take off and use in a new project if I wanted to build something like a Champ, or 5E3 setup.

Am I wrong in that? Maybe I'm looking in the wrong places for the way to build a from scratch tube amp. Where should I go to find out about that. I've done plenty of searches, and seems about half the websites I find are now shutdown, and for the price of a 'kit', I can buy a 1970's Fender Champ or better. Which I could use to build the same head/cabinet arrangement I'm talking about.

[BooneDog]

Thanks for all the advice guys, that's why I like this forum. I get the message and what I think I'm going to do is just hold off for now and spend a little more time educating myself. I may end up with a little amp like this or maybe not.

I'm going to finish my 2x10 cabinet, see what that sounds like with the amps I have. Heck, I'm surprised every time I play my little Vox DA5 amp, and with a speaker out to my cabinet, and it's effects, it might me all I want.
I'm going to chill out and spend a little time in Guitar Center playing those various amps and get a better idea of what I want.

Heck, I'm a little project heavy right and time short now anyway.
I have 3 from scratch(my first bodies to build from raw wood) tele's under way, and the cabinet.

[tele12]

The new Epiphone Valve Jrs. have outputs for 4, 8, or 16 ohms.

[BlueJim]

Originally Posted by muchxs

A kit build is easier.

+1

I found a weber 5E3 kit was pretty easy for my first time build. Since then I've picked up a used power and output transformer pair I'm trying to repurpose. It's a lot more effort to figure out how this will work.

[laird]

BooneDog, you're on the right track. The transformers are the biggest expense in building an amp, so buying a platform with reusable iron will save you big when you decide to tinker with the amp.

The BH5, VKR8, EVJ and Champ are all the same fundamental amp (one 12ax7 into a single-ended el84, or 6V6 for the Champ) and use the same core components. If you're looking for a platform to modify and experiment on, I'd look for the one with the easiest chassis to modify and the lowest cost... probably the Peavey or VJr. The net is full of custom builds in the VJr chassis. When you rip out the circuit board they're all equally serviceable inside, so i wouldn't be too concerned with that. Whatever has the most space to work with!

When you get to the 15w range it's pretty much impossible to spend less than $300 unless you have most of the components already... and choose a cheap design... and don't make any mistakes... well, you get the idea. :)

Multiple output impedances requires a multi-tap output transformer. No dice on the Royal 8. But for a first build I wouldn't sweat it, using a 4 or 16 ohm load on an 8 ohm output isn't going to cause a problem.

-Laird

[BooneDog]

Back and forth I go. What I ended up doing to getting a Blackheart Little Giant head on Ebay brand new for $152 shipped. Just a little more than the Peavey I was looking at and a lot of pluses for what I want to do with it.

The multiple speaker outs already there is huge for me, as I'll be experimenting with different speakers and speaker cabinets.
I like the layout with tubes mounted on top, will be a nice platform to custom build a new head cabinet around. In fact, I might do that out of really nice wood, like a flame maple and make a 'boutique' looking cabinet for it.
There are some mod kits out there, that I can play with and start learning about tube amps and how they work, including PTP wiring boards and stuff.
Thanks for the advice guys.

[muchxs]

Originally Posted by BooneDog

Back and forth I go. What I ended up doing to getting a Blackheart Little Giant head on Ebay brand new for $152 shipped. Just a little more than the Peavey I was looking at and a lot of pluses for what I want to do with it.

Good choice! The little Blackheart is well built to begin with. $152 is a good deal. Sometimes it's less expensive to buy something that's better suited to your needs than to try to make something else work.

[BooneDog]

My Blackheart arrived so I've been playing with that. I CANNOT BELIEVE how nice it is.
As far as construction, and sound? WOW! The cabinet is very sturdy and heavy, the chassis seems very heavy duty and quality. I like the layout, and when I opened it up, there is a lot of room in the chassis.

I'm very happy with it. It's sounds huge out of these speakers, I've heard some say this amp is too bright, and they cut the treble and boost the bass to compensate, but with these speakers in the cabinet I built, I sure don't find that to be the case.

It was very noisy when I got it. Seemed like it was amplifying things that weren't coming from the guitar.

I opened it up and made some minor changes described somewhere on the web, guitarnuts.com maybe? Anyway, just untangled and moved a bunch of wires around, disconnected a couple that go to the pcb board but apparently don't do anything, and I removed the metal cover over one tube. Not sure why that cover is needed? Doing those things made a HUGE difference, more than I really thought it would. I learned how to check the tubes for being 'microphonic' and they are not. From my description before, I was sure that they must be, but all that went away with the few changes I made.
I do hear a scratch when I adjust the volume knob, not any other knobs but when touch volume, it's makes an amplified scratching sound like the pot is not quite right. Very minor, but something I want to correct.

So I spent the weekend building my speaker cabinet. That 2x10 multiplied on me. I don't know how the heck that happened!?!?!?

This is my first cabinet to build, and it's right at the dimensions of a Fender Bassman 4x10.




I know you guys that do this on a regular basis will cringe at the photos below...


I butchered the baffle and will redo it. Long story, but I tried my Rotozip, but the only bit I had broke. Then a combo of template/router from the one hole I did cut, then part freehand with router. At some point, I knew I'd be redoing with a proper jig, so just cut the holes so I could frontmount the speakers to hear them.

I'm actually going to open those holes up and use this one as the frame to mount a grill cloth.
But it is sufficing now to let me test with. I originally planned to front mount the speakers, but I really didn't set the baffle back far enough, so I'll probably rear mount them. As it is, there is EXACLTY 1/4 inch from the front of the baffle to the front edge of the cabinet, with I'd left more.



My first cab, and honestly, I was just hoping I'd end up with a squared up, strong cabinet. No fancy box joints or dovetails. Just solid pine sides and 1/2 inch birch ply baffle front. The four sides are completely glued up and sealed tight, the front baffle I have mounted on the sides the the top and bottom floating, and I'll experiment with the back. From completely open to closed.

In fact, before I move the speakers to a better cut baffle, I'm going cut a port in the front, right in the center, and close the back, just to see what that sounds like.

This is one of the sides, with the braces. It all looks MUCH nicer now! All the glue is cleaned up and I even went back and sealed all the seams where the braces are attached. Cabinet is square and strong, and it looks good enough that I'm probably going to leave it a natural wood finish.



Obviously, I still have a lot to do on it. Redo the baffle, Grill Cloth/covering, finish the wood, install jacks for multiple ohm setups and properly do the speaker mount and wiring. But for now, it's making good sounds, and that's a good thing!


_________________

[muchxs]

Originally Posted by BooneDog

I do hear a scratch when I adjust the volume knob, not any other knobs but when touch volume, it's makes an amplified scratching sound like the pot is not quite right. Very minor, but something I want to correct.

There are two reasons for a volume pot to be scratchy, neither of which should apply to your relatively new amp:

1, The pot may be dirty. There really isn't any reason for it to be dirty unless you bought the amp used and the previous owner had a regular gig in the house band at a mud wrestling joint

or

2, The coupling cap adjacent to the volume pot is a wee bit leaky. Just a little DC on the volume pot will make it sound scratchy and no amount of Deoxit will fix it.

[JohnnyCrash]

Originally Posted by BooneDog

It was very noisy when I got it. Seemed like it was amplifying things that weren't coming from the guitar.

I opened it up and made some minor changes described somewhere on the web, guitarnuts.com maybe? Anyway, just untangled and moved a bunch of wires around, disconnected a couple that go to the pcb board but apparently don't do anything, and I removed the metal cover over one tube. Not sure why that cover is needed?

The metal cover is simply a spring tensioned retainer to reduce noise in the tube due to vibration. It is best if left on, as it reduces physical noise.

"... a bunch of wires that apparently don't do anything" DO NOT SIMPLY UNPLUG WIRES. If they didn't do anything, they wouldn't even be there to begin with.

Rerouting wires can definitely help reduce noise. Otherwise, I would re-plug in the wires you disconnected and put the tube retainer back on. There are better ways to reduce noise than random wire unplugging.

Originally Posted by BooneDog

Doing those things made a HUGE difference, more than I really thought it would. I learned how to check the tubes for being 'microphonic' and they are not. From my description before, I was sure that they must be, but all that went away with the few changes I made.
I do hear a scratch when I adjust the volume knob, not any other knobs but when touch volume, it's makes an amplified scratching sound like the pot is not quite right. Very minor, but something I want to correct.

A tube might not be microphonic, but can still be very noisey. They are not always the same thing.

Again, I would not recommend unplugging "unnecessary wires" - they ARE necessary. The tube retainer reduces physical/mechanical noise, and has little to no effect on typical operating noise (hiss, hum, crackling, etc). It helps againsts vibrational rattling type noise though.

Some potentiometer cleaner/lube may help the pot noise. I'd try that first since it's cheap and easy.

BE CAREFUL
Now that you fired the amp up, the capacitors can hold high voltage charges (even when off or unplugged). It may have a bleeder cap, but unless you know what you're doing, that is not a safe bet.

[BooneDog]

Thanks for the advice guys. Yes, amp is brand new, never used.

I know I was brief on my description of my 'fix' Johnny, but I wasn't randomly unplugging wires. I found reference to this in a few different places and mod sites for these amps, including AllenAmps. There is a brown and a white wire coming from the PT that apparently are not actually used in this amp, or not in this amp in this country maybe they are there for other applications. they made a place for them on the board to plug in, but the references I mention suggest either cutting them off and tying off, or unplugg and tie off out of the way. that's what I did. There is a whole batch of wires in the chassis from PT to power switch to board, power light, etc. that are in a wad and kind of stuffed on top of the board. I undid the random jumble, twisted them, and moved and tied them aside away from the board. (plenty of room for this). So, not random action on my part, these were things I found from the Blackheart forum, bitmo mod stuff, etc.

Thanks for all the other info, yea, I wasn't sure about the cover, I'll play around with putting it back. In this case, I do see how that is attached, with the spring on top that it could keep a secure connection.

Starting a new workweek, so little play for me for the next 5 days. I have the amp back together and will be spending the week getting to know it better in this state. Then looking into the volume thing next weekend.

[BooneDog]

Finally finished my speaker and head cabinet.