Danny finds ANOTHER Unicorn?! Jamo C803

hey everybody welcome back to gr research where we're doing another upgrade first though before i get into the upgrades let me say to all you guys uh thank you for besieging us with all the orders we've been getting especially all those orders on the new desktop mini we've had well over a hundred and something of those uh ordered from us already thank you very much uh we are waiting on things as usual i mean we're we're constantly blowing through raw materials as fast as we can get them in we're ordering everything they've got and everything everybody else has and we're still waiting on some resistors we've got more caps coming we've got more inductors coming over waiting on more nq drivers to get here to do some of the nx models but it's the moment that stuff arrives orders are going out the door we've got orders packed lined up with notes waiting what it's waiting for and a lot of orders we have everything we need and they're going out the door really quickly so some things are coming in and out pretty quick or pretty quickly some things are taking a little time i've been limited on the time i've had to spend doing upgrades which is something i enjoy doing and a lot of that is piled up a little bit but i am hitting it and working through it and getting some of them done this is another one that was sent to us this is a pretty nice little speaker it's a new yamo and i say yamo i've been saying jamo this is the model let's see here it's the model c803 and the thing i liked about this thing is the cabinets were pretty nice and the drivers are pretty nice it's got a really nice little dome tweeter it's kind of horn loaded uh silk dome the woofer had a lot of break up up at the top of the range but nothing that affected it within the range that it was playing so nice looking drivers uh crossover though eek um this one isn't even built on a circuit board this one it's not even point-to-point wired the connections are just dropped into little solder spots to make the connection um iron core inductor on the woofer circuit electrolytic caps there's a sand cast resistor there's one poly cap probably on the tweeter circuit with this little bitty inductor here that's the dental floss gauge it's tiny so um they put the money where they wanted it on the cabinet so it looks good to the eye to the ear though there's some stuff holding this one back quite a bit and yeah some feral magnetic screws and pretty cheesy binding posts so um how well did they engineer this thing actually pretty good let's look at some measurements i'm going to try and get uh ron to throw some of these up in kind of a split screen again we're going to look at some before and afters because i did not change this very much the guys who engineered this did a pretty good job so i went in and designed a network that really measured very similar to what they had i smoothed it out just a little brought the tweeter level down to where it's a little bit more balanced and kept it simple and it measures really really well and with the upgrade package that i've put together the parts quality is going to shoot way up and the performance is going to shoot way up it's going to sound a lot better than it did so let's look at some before and afters and let's look at just first the on axis frequency response and if you look at the before and after you'll see both are really smooth there's a little bit of a peak in the tweeter's response it's at about let's see that's two three four five k hertz four to 5khz there's a little bit of a peak i tamed it a little not much i couldn't tame it anymore without going in and putting a whole bunch of parts on it trying to put a notch filter on it and a bunch of stuff like that it just really really wasn't that bad it's a pretty small peak and in the off axis it drops off so that tells me let it be no worries um look at the crossover response if you look at before and after you can see i smooth things out a little as you as i mentioned when we looked at the on axis response balanced out the tweeter's response a little made it a little more level but other than that it's crossed very similarly to where it was before it's a fairly low crossover point but this tweeter is pretty robust and will handle it really well so very little change there actually it's almost at the almost at the same crossover point so no issues there at all what was really good about this speaker is the vertical off axis meaning as you start going up and down the driver stayed in phase over a really wide range and it maintained a really even response if you look at the before and you look at the after you notice it's about the same in that regard so it hardly changed it any uh same with the horizontal off axis if you look at the before you look at the after they look about the same now one thing i did do is i went in when i designed a network for it instead of just putting an inline resistor in line with the tweeter to bring the tweeter level down which made the impedance a mismatch so if you look at the impedance response of the factory curve you can see the tweeter level is much higher impedance than the woofer level what i did was went in and used an l pad to bring those levels down to where the impedance is more balanced all the way across so your amplifier sees the same load and it's a little easier to to drive that way and um spectral decay on this thing super clean really clean spectral decay so no ringing nothing stored energy this thing plays and stops great uh the cabinet was fair i mean it's it's got one brace running through it about right here so it's pretty solid there um it's got some foam liner on the inside i don't know if you can see it through this big hole for the binding post cut but it's just lining foam if we pull that stuff out of there and line it with no res it will tighten up a little of the cabinet ring and tighten up the bass response a little bit give it a little cleaner sound all that's going to come in the kit i put a little parts package together it's got one set of tube connectors that will replace one of these sets of binding posts if you want you can parallel the old binding posts so you can use either or but you really need to get these out of the signal pad so tube connectors all new wiring good quality parts uh sauna caps on the tweeter circuit uh the erc poly caps on the woofer circuit large gauge air core inductors on everything good quality resistors and all that came up to 285 bucks so if you guys own one of the yamos and you want to bring the performance level up quite a bit in clarity detail imaging all those things that are going to equate to getting these parts that create smearing out of the signal path then i've got a easy little package for you it's an easy upgrade you guys can have fun with it there you go but overall uh pretty nice design work on this one so got to give them props for doing a pretty good job but the budget counters are the bean counters they hit it pretty hard with you know i don't know eight dollars worth of parts there maybe 12. so they left a lot on the table good news we can make it a lot better so that's it for this quick little clip uh thank you everybody for tuning in be sure and hit the subscribe button i've got more videos coming i'm gonna try to shoot another one in a few minutes a different model um hang in there thanks guys

Channel: GR-Research

Views: 19,585

Rating: 4.9821429 out of 5

Keywords: Tuesday Tech Talk, audiophile, hifi, loudspeaker, fullrange driver, comb filtering, GR-Research, Danny Richie, crossover design, measurements, best loudspeakers, tube amplifier, preamplifier, diy speakers, audiophile speakers, audiophile music, amplifier, best voice, audiophiles, high end, baffle step loss, open baffle, fast bass, subwoofers, line source, drivers, high power handling, low distortion, the room, speaker upgrade, audiophile loudspeakers, crossovers, DIY Audio, soundstage

Id: HqOiuL5lzNI

Length: 8min 12sec (492 seconds)

Published: Thu Jul 22 2021