Meanwhile, back on the Monoprice amp... The "Black Friday"* price just kicked in. For US buyers this means you can now get the amp for $212 with free shipping. I should have waited a couple of days, but these are so often sold out, I did not think they'd come down in price and was afraid they might actually go up.
Too soon old, too late smart, as a buddy used to say...
*Big pre-Christmas shopping day the week of the US Thanksgiving holiday.
I tried a friends Harley Benton yesterday and was blown away, I'm thinking of losing the old AC30TB in favour of one or maybe two of these. Quite outstanding IMHO, could easily be the market leader
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I am impressed that you liked it that well. You'd need at least two to keep up with your Vox. It's the market leader in the 15W tube amp under $300. Of course it's the only one in that class...Originally Posted by impala59
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Just heard a Vox AV15 analog valve amp, at £159 (under $200 US) nice sound, but yet to try one myself it seems that the prices are moving in the right direction though😀
The AV15 is a hybrid amp. It has a single 12AX7, half is used in the preamp and half in the power amp circuit. Otherwise it’s all solid state. Thought it might use one of Korg’s ‘mini tubes’, based on a florescent display, but it’s a good old 12AX7, so is easy to replace if necessary. Which is not to say that it can’t sound nice, but it’s nothing like the Harley Benton.
From what I can see there are a bunch of amps from Vox that use either an 12AX7 or a "nutube" in the preamp. I *think* these all have class D power amps with a tube in the pre-amp. Since modern Vox is Korg, I am guessing they use some sort of digital modeling technology. I am always a little suspicious when a company uses the term "analog." In this case it seems to mean the the preamp signal is analog, but here may be some digital effects tech on board as well.
The Harley Benton/Stage Right is a fairly simple design. There are a couple of transistors in the reverb circuit, but all the gain/power in the preamp and amp sections seem to be from tubes. That said, a true 1960's tube amp (or even a modern one like a Blues Jr.) would have a tube to power the reverb. I suspect that the tube vs solid state may have a small effect on the sound of the reverb, but am also guessing it's not a lot, since there are pretty good reverbs in pedals. Traditionally there would also be a tube rectifier. I don't see how a solid state vs tube rectifier could make a difference in sound, but that could be because of how little I know about virtually everything electronic. Others may have a better take on this. Laney seems to have eliminated them in it's current tube designs which may be why the HB doesn't have one.
What's a little puzzling to me is why there aren't more relatively cheap tube amps. The tube set used by in the SR/HB/Laney is the same as a Blues Jr. which, and can be had for around $50 on the internet. I get why boutique hand wired amp using these tubes is expensive. But I don't quite get why an amp with a printed circuit board would need to be all that costly. After sinking about $100 in a speaker and tubes...it seems like the rest of the cost can't be much more than $50-75 in a factory context.
Diode rectification is far more efficient than a tube rectifier and responds to changes in current draw far quicker. So the attack on loud notes causes ‘sag’ with a tube rectifier that doesn’t occur with diodes. You can simulate sag with resistors in a diode rectifier circuit but most amps don’t bother. Weber make solid state rectifiers that fit in tube bases that allow a lot of ‘sag’ but are more reliable. So there is an affect on the sound, but mainly on the big transients.
Thanks for that Simon, thought it was too good to be true!
Guns, Guitars, Bikes and Cars and the love of a good woman who allows me to indulge
Factory prices are always going to be a small fraction of whatever you'd pay for them retail, even from a web supplier. But there will always be those markups at each stage, which means even small cost differences can make a big difference to the retail price. There are other costly items in valve amp you haven't mentioned, like input and output transformers and normally a small choke or two. Transformers are expensive and can each cost as much as, or more than, a speaker, especially in larger amps. The chassis is normally more involved than on a transistor amp, with lots more holes to cut. The valves need to be tested (at least a basic one to check they work) and inserting them is a manual job, that can't be duplicated by a pick and place machine like PCB components can. You also need large, high voltage rated capacitors, and those cost more than the ones you need for the switched mode power supply solid state amps. So there are a lot of small things that add up to a much more costly amp.
So I'd not ask why there aren't more cheap valve amps, but how they make that particular amp and sell it for so little? No idea what components they've used, but you can bet they will be of the lowest quality they can get away with. No idea what valves, but the typical low-price Chinese valves are never as good as the Russian or eastern European valve makes. Some of this may not make a difference when new, but in 5 years or so, things may not be so rosy with the amp. Using someone else's PCB design saves them time and money which doesn't have to be recouped, and a couple of large outlets like Thomann and Stage Right taking most of the factory output of the amp save sales, marketing and distribution costs. Again, all items that are added in to the cost price per unit and then have those markups added.
I had forgotten about the big caps and transformers.
At this stage I can only say note the quality on what I have seen. So... The handle looks good ;-) It has a low end Celestion speaker, JJ Tubes with retainers to hold them in and a MOD reverb tank. Construction looks reasonably good. Better than what I was expecting. There are a couple of reviews on youtube of folks that have taken them apart, without highlighting any damning flaws. Of course, I have no idea about what's inside the case other than what I have seen on youtube, and I understand about half of that. There were some reviewers that did not like the reverb tank, but they no longer ship with the one that got the complaints. I haven't heard complaints about the MOD.
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