Haze 40 crashed

[JimDep]

Say Reverb, were using JJ's in your Haze when you were having the problems? I've been reading about some other similar issues that players have been having, and the JJ's seem to keep coming up as a common denominator.

[reverbbb]

No. The were the Chinese/Marshall branded stock tubes. Apparently, I needed to change them after only 25 hours of use.

Tubes fail from time to time. But until now, I have never heard of them doing damage to the other circuits. I have seen a couple of other reports where tubes are damaging other circuits.

Thanks for the suggestion. I have always like JJs. That is what the amp tech put in as replacements. We'll see.

[JimDep]

I agree. I'm still wondering if it's the circuit or the tubes. I'm hoping it's the tubes of course. I'm so frustrated about these lousy tubes being sold, and used as stock tubes, but I'm not convinced about the quality of the components either. Most likely the tubes.

A few months ago to hear how it would sound, I took the stock 12AX7 Marshall tube from my AVT and put in the V1 spot on my Peavey Delta Blues. In about 10 seconds, it blew, and even cracked the glass around the plate! I still have the cracked tube as evidence (for what I don't know). I don't quite get why it blew. I put in a Groove Tube GS 12AX7 and it improved the quality big time on the AVT.

So you have JJ's in there now...if it happens again, don't go with the JJ's. Again I'm hearing other complaints similar to yours having to do with JJ's. We'll keep our fingers crossed.

[bonedaddio]

Tuning in late here, but what the hell.
I have two slightly modded Haze 40 combos. Early on with the first one, I had one of the Chinese EL34s fail, badly. This led me to really look into the amp, learn how to properly bias them, and make some tube changes. I use the clean channel, unbelievable tone and chime for the $$$, with pedals. When I got the second one, the first thing I did was check the bias... it was waaaaaaay off the factory spec (IIRC it's 39 mv or similar) so I biased them correctly. Then a mod or two...
Both amps have been used extensively gigging for years. Never failed. Only problem I've had was that the connectors on the power amp section can get "pushed off" by the insulating plastic covers (they compress when connected, and are pretty tough and springy) which requires pulling the chassis, clipping back the insulating covers of the connectors, tighten up with screw driver, and re-attach. That's it in two years, and it's because the amp fell over in the back of my car, and it wouldn't make any sound when I went to use it at practice. So my experience with them is overwhelmingly positive. I have to sell one now, as I just bought a JMD100 half-stack. Poor me!

[surfnorthwest]

Welcome to the Roadhouse bonedaddio.

The Haze is a very underrated Marshall IMO. In fact When guys are looking for a small combo I like to recommend them. I dont own one but as many of them out there you sure dont find this forum flooded with quality issues.

The bias drift can happen but Marshall does bias them correctly before shipping. I contribute many bias issues to modern production tubes.

Congrats on the JMD100, I have too. You will love it.

[bonedaddio]

Thanks!! I'm really pumped. Should have it by the end of the week.
I really think the second Haze 40 I got was never set right from the factory in India; but I'm no expert. I'm just glad I learned how to check and set bias myself, that alone can save bench charges, and it definitely helped how the amp sounded. Never new how important the output tubes were to the sound of the amp!

[BobK]

Mine has been gigged regularly for 18 months and, last week died in 'warm up' Phew! Took to my amp tech and it was a blown tube.

Turns out the previous owner made the mistake of only replacing one output tube, (should always replace the pair) and put in a cheap chinese replacement. Turns out for all this time the tubes were mismatched, not biased properly etc.

He said he was rather surprised it had lasted that long.


Great little amp. Sorry to hear your one has been a pain in the butt.

[MKB]

I owned a Haze 40 for several years and really liked it, only sold it as it was made obsolete by my JMD102 combo. The Haze 40 is an interesting beast; it is rather small for a 40W combo and maybe has the best size/functionality of any amp its size. It also has a low end response far out of proportion to its size. But this comes with a few drawbacks.

In order to get all that amp in such a small cab, the tubes are horizontal and very close to the speaker. Also, to keep a good low end response, the cab had to be made semi-closed and ported. This ends up being a brutal environment for the tubes, they are subjected to insane amounts of heat and vibration. Using the stock amp at loud volumes will torture all the tubes, and with the quality of modern tubes, there is no wonder that the Haze 40 will eat them. The biggest problem I had with my Haze was getting non microphonic tubes that would work in the thing. The amp actually destroyed a beautiful NOS Telefunken smooth plate tube I placed in V1, just shook it to the point of unusability. The only tubes I could find that would stand up in it were Sovtek 12AX7WB's; these are terrible sounding tubes but would handle the harsh environment and not die within hours (like the NOS Telefunken did).

That being said, after getting the tubes right, I gigged with the amp for several years with zero issues. The 4 button footswitch was terrific, if you have a Haze 40 you really need this footswitch.

Probably the best thing a Haze 40 user could do would be to disconnect its internal speaker and use an external one as much as possible, especially for prolonged use at high volumes. That would cure most of the tube destruction issues. It would also make sense to regularly replace the tubes before they have a chance to blow on their own. Most Haze 40 owners should resign themselves to doing these things if they plan to gig with it on a regular basis.

Having been in the Haze 40 many times, I can say it is a very well made amp, and the idea that the problems are due to it being made in India is completely unfounded. All of the problems I have seen were primarily due to design issues that are well known and were corrected during the production run, and tube issues caused by the brutal environment in the cab.

[MKB]

When I had my Haze 40, I gigged with it quite a bit over several years and never had it fail on me at the gig. The only issues I had was trying to get rid of microphonics, and the power LED would sometimes take a while to start (but the amp worked fine while the LED was off). I did have to use a specially picked low microphonic 12AX7 in V1 to make it usable, a Sovtek 12AX7WB was the only tube that would work properly. It might be the worst sounding 12AX7 I have ever heard, but the low microphonics made it worthwhile in this amp.

Unfortunately short tube life may just be something to expect in the Haze 40, due to the quality of current new manufacture tubes as well as the brutal environment inside the Haze 40 chassis. Perhaps it is kind of like a race car, when it works it is amazing, but you simply have to service it more than a family car. Get the best non microphonic tubes you can get, make sure the power tubes are new and heavily tested (like Groove Tubes), have a spare amp setup available for your gig, and enjoy the Haze 40 as it is a great little amp when it works right.