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Post by funkykikuchiyo on Jun 1, 2022 10:28:11 GMT -5
I noticed a while ago that when you start looking at non-Fender/Marshall vintage tube amp designs, one thing that happens very often is the cabinets get larger. For any given wattage/size, Fender seems to always have a smaller amp. A 15w 6v6 amp from Fender will have a smaller cabinet than an equivalent size amp from Gibson, Gretsch, Ampeg, etc. I tried doing some research a while ago about cabs to see if anyone had done any experimenting, but I came up with very little.
I've wondered what would happen if you took Fender amp designs and put them into larger cabs. So, take the cab dimensions of a pro-reverb (or Twin Reverb) and make it a Vibro-Lux. Make a Vibro-King, but keep it at the size of a Bassman or Super Reverb. Put a Princeton Reverb (still with a 10" speaker) into a Deluxe Reverb sized cab. The trends in modern amp design go the other way. A huge part of the Mesa/Boogie design is ridiculous power in a small box, and everyone else seems to follow that example. What would happen if we kept the box larger but the power lower?
Any thoughts?
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Post by Pinetree on Jun 1, 2022 11:29:31 GMT -5
Styrofoam.
Just saying.
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twangmeister
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Posts: 349
Formerly Known As: Twangmeister
Age: 72 and fading fast.....
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Post by twangmeister on Jun 1, 2022 12:26:11 GMT -5
I believe a bigger cabinet with the same speaker would improve speaker efficiency. Slightly. It would likely increase the bass response as well. Slightly.
Fender's post-tweed era tube combo amps are infinite baffle in design. I doubt that the tweed cabinet combos are tuned in any way other than to allow the amp heat an exit, so they are close to infinite baffle. Some Blues Jr owners have put their chassis into a modified tweed Deluxe cabinet claiming that it opened up the low-end.
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Post by funkykikuchiyo on Jun 1, 2022 18:47:27 GMT -5
. Some Blues Jr owners have put their chassis into a modified tweed Deluxe cabinet claiming that it opened up the low-end. Anyone here have first hand experience? That sounds like a perfect proof-of-concept experiment.
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Post by Leftee on Jun 1, 2022 19:15:55 GMT -5
Well, I had the whole thing typed up on my phone and FireFox crashed. I’ll try again from my computer.
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Post by reverendrob on Jun 2, 2022 0:44:01 GMT -5
Best proof of concept without blowing a ton is to simply run said combo through bigger cabinets/speaker options, i.e. run a BJ through a roomy open-backed 2x12 or equivalent.
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pdf64
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Posts: 558
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Post by pdf64 on Jun 2, 2022 6:50:30 GMT -5
… Fender's post-tweed era tube combo amps are infinite baffle in design. I doubt that the tweed cabinet combos are tuned in any way other than to allow the amp heat an exit, so they are close to infinite baffle... How are you defining ‘infinite baffle’? See techtalk.parts-express.com/forum/tech-talk-forum/30879-sealed-vs-infinite-baffle?p=396115#post396115As I see it, all the vintage Fender valve guitar amp combos are open back cabs. A typical Marshall 4x12 being an example of an (almost) infinite baffle. Here’s the 70s Fender Bassman 10, a valve combo with an infinite baffle / sealed speaker cab (not sure whether the baffle is ported though?)  |
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Post by Peegoo 🏁 on Jun 2, 2022 7:28:14 GMT -5
I've wondered what would happen if you took Fender amp designs and put them into larger cabs. Years ago I scratch built a 5F1 Champ chassis and a "tweed twin" cabinet for it. I reconed two 8" Quam alnico speakers and stuck 'em in there. It looks kinda goofy with that little window cutout for the amp controls on the top panel, but it weighs only about as much as a 1x12 speaker cabinet, and it sounds pretty huge.  |
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Post by funkykikuchiyo on Jun 2, 2022 9:07:45 GMT -5
I've wondered what would happen if you took Fender amp designs and put them into larger cabs. Years ago I scratch built a 5F1 Champ chassis and a "tweed twin" cabinet for it. I reconed two 8" Quam alnico speakers and stuck 'em in there. It looks kinda goofy with that little window cutout for the amp controls on the top panel, but it weighs only about as much as a 1x12 speaker cabinet, and it sounds pretty huge. Yes! This is exactly the sort of thing I was hoping to see!
GASing really hard (AASing? Let's not go there) for some sort of 2x10 in a larger cab than a typical Vibro-Lux....
Seems like the best of both worlds to me. Plus, a bigger amp that is also light is easier to move than a small amp that is super heavy. Back when I had an SRRI people would comment on how bulky it was, but it was actually very easy to move because I didn't have to lean so far to the side to grab it, and it was easy to hoist up in front of me.
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Post by funkykikuchiyo on Jun 2, 2022 9:10:20 GMT -5
Best proof of concept without blowing a ton is to simply run said combo through bigger cabinets/speaker options, i.e. run a BJ through a roomy open-backed 2x12 or equivalent. Good call, but BEST would control variables... so, a roomy 1x12 cab, maybe even using the same speaker. |
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Post by Leftee on Jun 2, 2022 9:24:55 GMT -5
I can come at this from the Marshall world, but still not provide empirical evidence. The following are just my own observations. In the '80s with the launch of the JCM800 line Marshall really branched out from their traditional head and cab configuration. Before the JCM series they did make combos, but those were relatively few in number and largely 2x12s. There are, of course, exceptions. In the JCM series they launched a complete line of SS combos and heads, with the combos being the bigger sellers of the two. Marshall also expanded the tube line with a plethora of combos. I'll focus on the amps I currently own. I suppose I do have the means to delve deeper into this topic between all these amps. All the amps are open back. Lead 12 Reverb (5205) - Small 12w 1x10" combo. 17x14x8 These (and the 5005 - non-reverb) sound pretty boxy. I mod these by installing a stacked op-amp for IC1 and a speaker swap of some sort - either a Celestion V10 or a 10" Greenback. The stock G10D is a fairly misrable speaker that sounds quite tinny and sterile. Even with these mods the amps sound boxy (small). Lead 20 (5002) - Larger 20w 1x10" combo. 17x19x10 Speaker is a Celestion G10L-35 which is an exceptional "Marshall" type speaker from the era. This amp sounds quite a bit better than the Lead 12 and not nearly as boxy. Master Lead Combo (5010) - 30w 1x12" combo. 23x19x10 Speaker was the miserable G12M-70. This amp begs for a speaker swap and is a great sounding amp once that is accomplished. I have a WGS Invader in mine which is akin to a higher-power G12M-25 which a slightly subdued top end. This amp sounds great and is less boxy-sounding than the two listed above. The above-listed amps all have the same basic preamp structure. Master 75 Reverb (5275) - Small 75W 1x12" combo. 17x19x10 Originally came with a Celestion Sidewinder which was an efficient somewhat full-range speaker. I think they were chasing Randy Rhoads tone. The amp is loud as original sin. It does sound a bit boxy - even with its relatively high power. I had one of these, back in the day, and plugged it into a (Marshall) 1936 2x12 (closed back cab) during rehearsals and gigs. It drove that cab great and sounded so much better. Studio 15 (4001) - This is a small 15w all tube 1x12 combo. 17x19x10 It has some firsts/innovations for Marshall. It was their first amp to use 6V6s. The amp also had a headphone out that mutes the speaker out. And lastly - and of great significance - it has a PPIMV. The amps came stock with the Celestion/Marshall "Vintage" speaker which later became the V30. These are great playing/sounding amps... but boxy. All this to say that my observations are that... the greater the distance between the front of the cone and the back, the bigger the amps seems to sound. It also seems that the smaller cabs lack bass. Too much cancellation between the front and back of the speakers?
Measurements added.
Interesting to note that the 5002, 5275 and the Studio 15 all use the same cab.
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Post by Leftee on Jun 3, 2022 11:08:39 GMT -5
I was thinking about my post...
I think a large part of the "boxy" description is lack of bass. At least in my mind.
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Post by funkykikuchiyo on Jun 3, 2022 17:56:37 GMT -5
I was thinking about my post... I think a large part of the "boxy" description is lack of bass. At least in my mind. Yeah, a lot of small amps sound "boxy" to me, where it is all honk. It reminds me a bit of when you get one of those little bluetooth speakers to pair up to your phone. Larger amps sound more dynamic, rich, and almost acoustic in their detail. I think we might be thinking of the same thing...? |
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Post by Leftee on Jun 3, 2022 18:41:34 GMT -5
I think so.
I was also thinking that Marshall released the Lead 12 as a head with 2 1x10 cabs. The cabs are mostly closed back except for small oval openings in the backs to act as handles. This set up sounds better than the combo, even if only one cab is used.
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Post by Lesterstrat on Jun 4, 2022 10:16:41 GMT -5
Best proof of concept without blowing a ton is to simply run said combo through bigger cabinets/speaker options, i.e. run a BJ through a roomy open-backed 2x12 or equivalent. I used to run my Pro Jr. through my Germino 4x12 once in awhile around the house. It was different, but not nearly as much as one might think. To me, if you really want a BIG sound, especially live, there's just no other way to go than with a 100 watt head through a 4x12. There's just no replacing those big transformers. That said, I only brought out the big guns for large venue shows. I was not going to lug around 4x12s in clubs where a bunch of drunks couldn't tell the difference. lol |
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Post by reverendrob on Jun 6, 2022 2:01:18 GMT -5
Yea, I want the big iron period - but for tubes, I generally want 6L6 Fender as my starting happy point.
I'm warming to Marshall stuff finally but not by itself - in a stereo rig, yeah, all day.
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DrKev
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It's just a guitar, it's not rocket science.
Posts: 424
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Post by DrKev on Jun 6, 2022 7:56:22 GMT -5
Very few tests have been done using the same speakers in different size cabinets but from the few I have seen on YouTube that are useful I suspect that top-to-bottom and side-to-side dimensions make a difference but front to back not so much (for open cabs at least). The Boogie Fillmore amps are a good comparison. The 25 and 50 watt combos have the same speaker and same cabinet depth but different sizes.
Also, most 10" speakers come in tiny boxes which kill the low end, even though a comparison of manufacturer's frequency response curves suggests a small difference in the bass end.
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Post by Leftee on Jun 7, 2022 13:10:30 GMT -5
Very few tests have been done using the same speakers in different size cabinets but from the few I have seen on YouTube that are useful I suspect that top-to-bottom and side-to-side dimensions make a difference but front to back not so much (for open cabs at least). I dunno... I posit that the depth also adds to the separation between front and back of cone. Would that not also reduce cancellation? |
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