NAD: CJ's Cavalcade of New Smallish Cheapish Amps - #1

[culturejam]

I had some ebay bucks burning a hole in my virtual pocket, so I figured I'd see if the MonoPrice / Stage Right 5W 8" tube combo amp was worth a damn. Best $92 amp I've ever bought. 

Some of you probably know that MonoPrice doesn't actually make anything. They get private label stuff from manufacturers and resell it. But they are very good at choosing nice stuff and selling it at irresistible price points. I have one of their mini 3D printers, and it's excellent (and cheap as all hell).

Based on my readings on the interwebs, this amp is just another rebadge of the Laney Cub 8 (itself just a rebadge of some nameless non-brand amp). That pretty much means it's a Champ clone with a simple tone control added between the preamp and power amp. There is also a switch on the front panel that says "5W / 1W", but it doesn't actually change anything regarding voltage and it's not a pentode / triode switch. All it really does is add more input resistance to load the guitar pickup more. Still, it works well and doesn't have a big impact on tone. I'd guesstimate that it drops volume by about 25% and there is a small amount of overall gain reduction (which may or may not be a good thing depending on your application).

Considering the tiny cabinet and 8" speaker, it sounds very good. The output tranny is pretty small, but it doesn't seem to lack in the low frequencies. With stock tubes, it favors single coils for max headroom, as humbuckers drive it pretty early on the Volume knob (a little hair shows up around 3 on the dial). The Tone control is very responsive all the way around, but there is a big jump right near the end of the sweep (clockwise). The way Tone is set up in the circuit, it also sort of acts as a gain control as well. Between Volume, Tone, and the "Watt" switch, you can get a lot of sounds, especially if you play with your guitar's controls as well.

Stock 6V6 is Sino clear glass (6V6GT). Honestly, I think it sounds just fine. The preamp tube is totally unmarked, but the documentation says it is 12AX7. It must be a low gain 12AX7, because I swapped in a JJ ECC83 and it had noticeably more preamp breakup. I ended up putting in a JJ ECC81 (12AT7) to get a little more headroom, and it really works nice. Since I had a single, I also put a JJ 6V6 in there. I'll play that for a few weeks and then put the stock 6V6 back in and see if I can hear a difference.

The only thing I wish it had was a master volume, but it's a Champ, so there ain't one. I can probably get where I need with just my guitar volume. I think there is enough room for a 10" speaker if I cut the baffle a little bigger.

For $100 folks, this one is a no-brainer. As with many of these Asia-made amps, you can't come close to buying the parts for the asking price of a finished amp.

[matmosphere]

Cool. Those have a good reputation from what I've seen.

I actually was looking at the 15watt yesterday trying to figure out if it could work double duty for a little guitar and bass amp.

[287m]

Nice amp! im go to youtube now

btw, if you put Stage Fright in front of this baby, raise the bar of COOL meter?

[Leevibe]

That looks like a sweet little amp. I didn't know MonoPrice was selling them but I'm not surprised. And I think you're right. They do a fantastic job of finding great stuff to sell at really sweet prices.

[ahiddentableau]

[Picture emoji with a big thumbs up in your mind--there it is!]

Did you open it up and snoop around?  I'm wondering about it as a mod platform.  Does it run at proper high voltages?  Does it have room in the chassis?  That kind of thing.

[pickdropper]

That looks very cool.  Seems pretty well constructed for that price.

Not sure I totally agree on the quality of all things MonoPrice.  I've gotten some very well made things from them, but some of the stuff was absolutely terrible quality.  You just kind of have to order and see which category it fits in.  ;-)

[stringsthings]

I've thought about getting one of these.  Good review.

[alanp]

If it does break, that's a good excuse to crack it  open and use it as a base for a modded valve amp circuit

A tweed Champ is the obvious candidate. Just get a metalshop to drill a hole for the rectifier.

[culturejam]

Did you open it up and snoop around?  I'm wondering about it as a mod platform.  Does it run at proper high voltages?  Does it have room in the chassis?  That kind of thing.

Didn't check voltages, but I have no reason to doubt it's running at a "standard" B+ for this type of amp.

I think it might be easiest to pull the board completely and replace it with something new. A lot of the resistors are surface mount, and while changing values is not too bad, doing ad-hock mods that require adding new parts or running wires might be a bit tricky. But there's some room inside for a new board.

[ahiddentableau]

Thanks for the pics!  That was super helpful.

I gotta say, it looks pretty sweet as a mod platform.  Lots of room for a turret board in there, and even for an extra pot if you move the lamp.  Even the iron looks better than I would have expected.  I'm very tempted to get one and turn it into a BF/SF champ-style.

[junkemail86]

I've been interested in this one already, now I kinda want one.
Have you tried it with a 12 inch external speaker?
I tend not to like 8 inch speaker sound

[culturejam]

Have you tried it with a 12 inch external speaker?

Believe it or not, I do not currently have a functional 12" cabinet. My main cab for the last few years is an oddball Blackstar 4x8", which looks like an oversized 112. I'll definitely hook it up and give it a listen.

I do have a spare 10" cab that I can do a listen test with, however. And I highly suspect that a 10" speaker will fit in the Stage Right cab.

[culturejam]

So I got a really cool old-stock Tung Sol 5881 on ebay for $5 (shipped!), and my understanding is that as long as the power tranny can handle the additional current draw, there's no harm in subbing that in for a 6V6.

I was going to report my findings with this post, but I ran into a problem: all of a sudden the amp makes no noise at all. Stupid cheap amp! 

I tested all the usual things (tube swap, cable swap, speaker swap, guitar swap) and then pulled the chassis out again. During my last foray inside, I just took pics, didn't move anything or disconnect anything. Then I noticed the preamp tube is glowing as normal up when the power is on, but the power tube is not glowing and does not get warm/hot, even after being on for 10 minutes. I checked the fuse, but it was fine.

Finally, decided to reflow all the tube socket pin joints. And that was the problem! I guess there was a weak joint that was cracked when I changed out the tube a few times.

So now it's too late to test out the 5881, but I'll update this thread tomorrow.

[gordo]

The Laney versions I repaired had the same problem. The amps would shake themselves to bits. The store I was doing repairs for dropped the Laney line but if I recall once I reflowed the sockets I don't think any of them had issues or came back in again. 

[culturejam]

The Laney versions I repaired had the same problem. The amps would shake themselves to bits. The store I was doing repairs for dropped the Laney line but if I recall once I reflowed the sockets I don't think any of them had issues or came back in again.

Awesome. I'll also reflow the preamp socket pins just to be safe.

BTW, I just plugged this into my weirdo Blackstar 4x8 cab, and it sounds so much better. I mean, that's hardly surprising. Kinda makes me think I ought to just build a small head shell for it and toss out the combo cab. Or maybe first try putting a 10" in there.