Vox AC10C1 is a hybrid amp?

[mnutz]

I thought this deserved a thread of its own.

In another thread here on tdpri it was discussed that the AC10C1 uses transistors in the pre amp. We all know it has digital reverb, but I don't think anyone realized this newest info and Vox certainly wasn't forthcoming with it.

Does it matter? Do you care? Is this common with other "all valve" amps?

Apparently the often maligned AC4C1-12 does not use this topology. It is truly "all valve".

 

[Mad Kiwi]

I'm sorry I don't have anything to add to the Ac10 comment other than if it sounds good does it matter?.......and my small shop demo it did sound good but much louder than I expected. Which i doubt transistors can be blamed for

However, I am interested to know about the "often maligned AC4C1-12" comment or links? (hoepfully without derail)

 

[mnutz]

I'm sorry I don't have anything to add to the Ac10 comment other than if it sounds good does it matter?.......and my small shop demo it did sound good but much louder than I expected. Which i doubt transistors can be blamed for

However, I am interested to know about the "often maligned AC4C1-12" comment or links? (hoepfully without derail)

A common complaint about the AC4c1-12 is that it is too bright. Folks complain about that on forums all over the net. Lots of people attempt to mod the amp to take away what they deem as excess brightness.

I agree the AC10C1 is a good sounding amp. I don't agree with it being marketed as an all valve amp with digital reverb, if transistors are being used in the preamp for gain staging.

 

[Dacious]

I have a Marshall Mini-Jubilee with clipping diodes for the pull-rythym clip (like the old ones). It is awesome for dialling up instant Accadacca at reasonable volumes. If you like you can leave it unpullled for pure EL34 crunch.

Do you play through an amp with digital reverb? Solid state rectifier? Hate to tell you this, but capacitors and resistors and pots all vary the tone and output of amplifiers and they're not tube. Do you play through pedals with chips?

The AC10 is still overwhelmingly a tube amp. Pull the preamp tubes - no sound. While we might say the 'purity is tainted' also consider the price point. The AC10 one of the better implementations of ss components.

A hybrid is usually considered a tube buried in starvation low-voltage mode in a SS preamp to give it some vestigial 'tubiness' - more for bragging rights. The Vox does use HT transformer to drive tubes to 300+ volts, has a proper push-pull impedance matching transformer output section. It's a tube amp. If you like, with SS augmented preamp.

 

[Il Duce]

Interesting! I guess all of the rave reviews that the AC10 have gotten must be wrong because we all know that a amp can't sound great if it's not all tube! Lol

 

[tarheelbob]

Interesting! I guess all of the rave reviews that the AC10 have gotten must be wrong because we all know that a amp can't sound great if it's not all tube! Lol

I know, right? Thirty-seven pages and 726 posts (many of them mine) praising this great amp must all be pointless, now.....

 

[mnutz]

Interesting! I guess all of the rave reviews that the AC10 have gotten must be wrong because we all know that a amp can't sound great if it's not all tube! Lol

Nope not saying that at all. I think the AC10C1 is a great sounding amp!

I haven't played the AC4c1-12, but I have played through older versions of the AC4.

I think it's interesting that everyone says the AC4 has to be cranked to sound good, typical of a lot of tube amps, but the AC10 sounds great at bedroom level, typical of solid state amps.

Do those transistors in the preamp contribute to that good sound at low volume?

 

[mnutz]

I know, right? Thirty-seven pages and 726 posts (many of them mine) praising this great amp must all be pointless, now.....

No where in my post did I say that.

 

[mnutz]

Seems to me this is a situation like when the Super Champ was introduced and everyone thought it was all tube on the clean channel.

 

[Dacious]

Nope not saying that at all. I think the AC10C1 is a great sounding amp!

I haven't played the AC4c1-12, but I have played through older versions of the AC4.

I think it's interesting that everyone says the AC4 has to be cranked to sound good, typical of a lot of tube amps, but the AC10 sounds great at bedroom level, typical of solid state amps.

Do those transistors in the preamp contribute to that good sound at low volume?

The AC10 also has a pad-type power attenuator. I'm not disposed to them myself but it increases the amp's versatility, by letting it develop power but cutting it through the resistor.

The comments re:the versions of the AC4 of which there's been about 4-5 seem to focus on the preamps in the early smallbox one with the sealed cabinet speaker. The later versions seem to get a better rap. But even so, Topboost on top of a SE EL84 limited power section it's going to be tougher to get 'the 'sound'.

A small single-ended amp is inherently going to be more limited as to the volume and equalisation points it sounds 'good'. Too low a volume, no balls through a small speaker. Too high , goes farty.

The AC10 it seems the chip probably buffers the signal through the preamp. Not sure of their reasoning but it obviously works. I don't think they're using it for high gain.

To bring the amp in at that price point they had choices to make to include the 'Topboost' circuit.

 

[Big tuna]

I pulled the back panel of mine off to see if a speaker replacement is option and thought man what a pc board and why didn't they put this here and all that crap i do. But these are some great sounding amps. Yeah i wish it had a real tank in the bottom and it was hand wired. But would i pay the price. I still have mine a year later.

 

[Il Duce]

Nope not saying that at all. I think the AC10C1 is a great sounding amp!

I wasn't directing my comment at you, it was more of a general observation. I just kinda find it funny the way that our minds can be manipulated when we believe that something is different from what it is.

 

[3-Chord-Genius]

1) I've mentioned this elsewhere, but many Marshall JCM800 and JCM900 amps utilize clipping LEDs in their preamps, and while some may dislike the Marshall tone in general, nobody is saying that those amps suck.

2) This thing with the AC10C1 (I own one, FYI) is probably the best example to date illustrating how little solid state vs. tubes matters; as others have stated, the tone of this amp is almost universally praised. I like it better than my AC4C1-12 (all tube) and my Ac15C1 (all tube, I think). It's not whether there is solid state in the circuit that matters, it's how it's used.

 

[Dacious]

1) I've mentioned this elsewhere, but many Marshall JCM800 and JCM900 amps utilize clipping LEDs in their preamps, and while some may dislike the Marshall tone in general, nobody is saying that those amps suck.

2) This thing with the AC10C1 (I own one, FYI) is probably the best example to date illustrating how little solid state vs. tubes matters; as others have stated, the tone of this amp is almost universally praised. I like it better than my AC4C1-12 (all tube) and my Ac15C1 (all tube, I think). It's not whether there is solid state in the circuit that matters, it's how it's used.

Well, I wouldn't go so far as to say it doesn't matter whether it's tube or ss. In the case of the AC10, I'd bet they've used an AC4/ dinky power transformer, so the extra 12AX7 heater current might just be a tad too.much on top of the extra EL84.

Considering it's price point, and the results which is a tiny footprint amp with more than decent sound at a bargain price. It's really a sweet spot crossover between a bedroom and jam amp, small gig/micced. $50 more it's probably too close to the AC15 in price..

I think it's more successful than Fender's small-medium amps with chips in the preamp for reverb.

 

[Silverface]

In another thread here on tdpri it was discussed that the AC10C1 uses transistors in the pre amp. We all know it has digital reverb, but I don't think anyone realized this newest info and Vox certainly wasn't forthcoming with it.

While I have not seen a schematic, the layout of the chassis - with two 12AX7's and two EL84's - seems to indicate the preamp and power amp are both tube. It appears the transistors are on the reverb board wiht the digital chip.

That essentially makes it *not* a hybrid, but with digital reverb -not uncommon today.

I could be wrong, but with the chip and transistors on the same board it wouldn't make sense any other way. Not with the modular circuit board systems virtually every manufacturer uses.

 

[sliberty]

I posted the link to the schematic in another thread. Here it is again. The schem shows two MOSFETs in the preamp, besides the digital Reverb. One appears as the first preamp stage, and one appears right before the phase inverter. Having said that, both the preamp and the power amp contain tubes. So, I think it is fair to say it is a hybrid, however not in the way we typically think of hybrids. They usually have an all ss pre, or an all ss power stage. Here the preamp is "assisted" by MOSFETs. And I think we all agree the results are very good.

http://dealers.korgusa.com/svcfiles/AC10C1_SManual.pdf

 

[sliberty]

The AC10 also has a pad-type power attenuator.

No it doesn't. It has a typical Vox style master volume. You might be confusing it with some other amp.

 

[Musekatcher]

A hybrid is usually considered a tube buried in starvation low-voltage mode in a SS preamp to give it some vestigial 'tubiness' - more for bragging rights. The Vox does use HT transformer to drive tubes to 300+ volts, has a proper push-pull impedance matching transformer output section. It's a tube amp. If you like, with SS augmented preamp.

Fair, and I do think Vox does good designs to better emulate tube-ness. The question is, are they allowing folks to predictably assume the product is equivalent to an all-tube design? I think the OP is suggesting that's too convenient to be completely honest? And, it does matter when you are competing for $$ in apples-apples. Otherwise it would be pure tube-tube, instead of not.

 

[3-Chord-Genius]

Fair, and I do think Vox does good designs to better emulate tube-ness. The question is, are they allowing folks to predictably assume the product is equivalent to an all-tube design? I think the OP is suggesting that's too convenient to be completely honest? And, it does matter when you are competing for $$ in apples-apples. Otherwise it would be pure tube-tube, instead of not.

I don't think Vox is being dishonest at all in their description of the amplifier. I think the issue is that we as gear fanatics are far more neurotic about things like definition of "all tube" (which to me simply means tube preamp and power amp), "hybrid" (which to me means either the preamp or power section is tube and the other is solid state, etc.) If Vox uses a MOSFET to slam the signal harder into the preamp tube, great! Vox knows tone and how to achieve it, and I don't think that can be disputed.

 

[burntfrijoles]

I don't it matters much. After all, how many people put pedals in front of their signal chain to goose it?
My only question about the AC10 is whether it's overly bright or whether that can be tamed?