Soundcraft Vadis 201 Combo - Part 1

Подписаться 8 тыс.

Просмотров 1,6 тыс.

50% 1

Summary:
- No signal on either channel.
- Open circuit plate resistors and corroded valve pins in preamp, blocking signal at respective triodes.
- Once signal established, other issues became clearer.
- No reverb driver or return.
- Intermittent valve pin/socket interface.
- No tremolo.
- Crackling, dirty pots.
- Dust and dirt throughout chassis and cabinet.
- Ringing & microphonic EL34's, otherwise operational.
- 5Y3 presently testing OK.
- Speaker tested OK.
- Full re-cap (replacement of all electrolytic capacitors) advised, given the amplifier's age.
- Other improvements to be made if quote approved: Elevated heater supply for lower hum levels, Rectifier backup diodes added to protect amplifier and continue functioning in the event of a rectifier short, flyback diodes installed for output stage protection in the event of an open circuit speaker output.
Webpage: www.bradsguitargarage.com.au
Facebook: bradsguitargarage
Instagram: / bradsguitargarage
Equipment:
Soldering:
Pace MBT station w/SX100 & PS-90 handpieces
Hakko 474 w/815 handpiece
Hakko 936 w/907 handpiece
Hakko FX-888D w/FX-8801 handpiece
Quick 861DW hot air station
BOFA fume extraction unit
Loctite Multicore solder (C511 / 362)
Test Equipment:
Fluke 11, 175, 177 & 179 handheld DMM's
Tektronix 2236 analog oscilloscope
Rigol DS-1054z digital oscilloscope
BK Precision 4017A sweep / function generator
BWD 160a function generator
HP 6236B triple output DC power supply
Kyoritsu 3132A insulation / continuity tester
Video equipment:
Overhead cam: Panasonic HC-V785 w/Audio Technica AT9946CM mic
Handheld cam: Panasonic DC-G85 w/Olympus M.Zuiko Pro 12-40mm f/2.8
On location cam: Panasonic DC-GH5s w/Panasonic-Leica 9mm f/1.7 & 12-60mm f/2.8
Capture card: Magewell HDMI USB
Editing: Adobe Premiere Elements
Hand Tools:
Wiha, Felo, Stanley screwdrivers
CK & Engineer cutters / pliers
RS Pro wire strippers
Sidchrome & Gear Wrench spanners, sockets & shifters
Veritas planes & chisels
Materials / Consumables:
JJ's / TAD electron valves
Elixir / Ernie Ball / D'Addario / Rotosound strings
Electrolube & DeoxIT cleaners, lubricants & chemicals.

Опубликовано:

15 сен 2024

Ссылка:

Скачать:

Готовим ссылку...

Добавить в:

Мой плейлист

Посмотреть позже

Комментарии : 27

@Splattle101 Год назад

Nice old Phillips Miniwatt 12AX7s. I've had a bunch of those pulled from old gear. They've all been really nice, although a few were too microphonic for preamp duty.

@goodun2974 Год назад

Some years back I had about 3 dozen tube-based plug-in op-amp modules, made by Philbrick, that I scavenged from an industrial warehouse that was being cleaned out. They used two Telefunken diamond 12AX7/ECC83's per op-amp! Sold the tubes on eBay for a pretty penny, and got good money for the plug-ins as well. I got some amazing stuff from that place even though I kind of got there too late and only had time to scratch the surface so to speak before it all got carted away. The building had been 90% cleaned out and emptied into 2 big dumpsters before I got there, and the dumpsters were piled high and filled almost to the top. I was only able to root around about a foot and a half or so deep into the dumpsters; I scavenged power and output transformers, variacs, tube sockets and resistors and capacitors, and all kinds of stuff like that (but almost no tubes). There had to be a lot more great stuff closer to the bottom of the dumpster, but without ordering in a 3rd dumpster to transfer over to and spending days of digging it would have been impossible to find all the good stuff let alone actually take it with me. As it was, I paid $200 and sold everything for about 5k. I remember that there were entire flats containing a hundred selenium rectifiers per carton, of all things. I didn't take those with me because there wasn't any use for them ( toxic waste) and unfortunately they probably all ended up in a landfill. To this day it kills me to think of the things that were in those dumpsters that I didn't have time and energy to dig out. Inside the building I did find a pair of tube-type regulated power supplies that used two Mullard EL34's per unit to do the regulating!

@Splattle101 Год назад

@@goodun2974 My brother dug up a regulated supply from some old lab equipment, barely used. It had a (virtually) brand new KT88 in it, clear glass and GEC screen print in perfect condition. He's an audiophile and had no use for a single KT88, so he gave it to me on the condition I build it into a really obnoxious single-ended guitar amp. He said it was a matter of principle cuz it would really aggravate his audiophile acquaintances to know that perfect old KT88 went to vacuum tube hell. 😆

@goodun2974 Год назад

@@Splattle101 I have a pair of Heathkit W5M ultralinear mono block power amps that I got for free from the dump with GEC KT66s in them, although one pair has almost no emission unfortunately ( The other pair test excellent however so I probably have to check over the amp with the bad output tubes very carefully for faults). I've been recapping and rebuilding them a little at a time but haven't got either one up and running yet. I'll have to dig up a good quad set of 6L6GC's or KT66's elsewhere, and the existing good pair of used KT66s will probably go into a guitar amp , As long as they don't rattle and aren't microphonic.

@fiddlix Год назад

Looking forward to the conclusion on this one. Excellent content….sweet as..!

@simonkormendy849 Год назад

Wow, I seem to remember working on a very similar Vadis amp for an old mate of mine in the late 90's.

@tedmich Год назад

Thats some decent bite from the old amp, sounds good.

@victorbeebe8372 Год назад

Aloha and Mahalo Brad! Always interested on your video.

@BradsGuitarGarage Год назад

Always good to hear from you, Victor! And thanks for joining us on the livestreams.

@johnwilliamson467 Год назад

Chassis is both the singular and plural spelling of a chassis the plural is is eez rather than ee spoken ending . Engrish ( sic ) what a fine structured of a language . Elna builds a fine cap if it 15 years old it has served it purpose really. These are working machines not museum pieces . Cap have made very great strides in the last 20 years. If one does not know that a thermionic valve is also called a tube best read more .

@kbkman7742 Год назад

The Sydney made MSP 12pq alnicos sound cool too

@goodun2974 Год назад

The shielded signal wire carrying the audio from the top mounted preamp to the amp chassis is twisted and bundled up with heater and B+ wiring, so it's no surprise that the amp hums! Separate the signal cable out of that wire bundle for lower noise..... PS, I noticed that the phase inverter signal is coming from the top mount preamp and therefore the shielded cable must contain 2 conductors plus the shield, which does at least offer some common-mode cancelation.

@BradsGuitarGarage Год назад

The PI is actually in the PSU/PA chassis, so no luck there. There was coax feeding that chassis from the preamp, but the hum was addressed by the re-cap. Weird things were happening with the 70's Elnas.

@goodun2974 Год назад

@@BradsGuitarGarage , interesting, as the only tubes I saw in the PS/Amp chassis were the output tubes and the 5Y3 rectifier. BTW, I've never seen 500V Elna caps; but I've replaced thousands of low voltage Elna caps in old SS hifi gear.

@jerrylondon2388 Год назад

Love the Aussie amps, always interesting. Is Vadis someone's name?

@BradsGuitarGarage Год назад

Not sure. Check out www.ozvalveamps.org for more info and history.

@jasonnoonzio3473 Год назад

I'm wondering if plessey is the same mob that made plessey 2way radios many years ago

@ptk4476 11 месяцев назад

I have a 601 slightly older than this, and in much worse shape. I was surprised when you said cathode bias, the whole circuit looks to be very similar to the 601 otherwise.

@ghostface_grilla1155 Год назад

Nothing ruins a good time like people 😂🤣😅

@BradsGuitarGarage Год назад

You know it!

@bartnettle Год назад

LOL disintergrating particle board. LOL once wet

@goodun2974 Год назад

Particle board isn't so bad compared to Homesote, a compressed-paper wallboard (i call it "mother of wasp's nest) that predates sheetrock, and was used to make Danelectro/Silvertone amp cabinets.

@johnvcougar Год назад

Bunnings sell some particle board restorer, probably not that much better than watered-down white glue, but it seems to work ok to stop all the nasty flaking.

@goodun2974 Год назад

@@johnvcougar , water-thin superglue would probably be better.

@johnvcougar Год назад

@@goodun2974 maybe, but you'd need a ton of it, and it stinks and not very safe.

@goodun2974 Год назад

@@johnvcougar , if you wanted to reinforce the corner joints (the weakest point) of a particleboard cabinet, a 4 oz bottle of Titebond *thin* superglue, costing $15 to $22, would likely be enough. They claim it sets in 7 seconds! Anyway, super glue reacts with cellulose materials such as wood fiber and so it sets up really really quickly, and if you needed to you could always give it a spritz of super glue accelerant. A water based glue, thinned down, might tend to expand the wood or particleboard fibers as it soaked in, and might actually weaken the particle board, but super glue would set up quickly without changing the particulate structure. PS, superglue sets up faster in the presence of moisture, and so if the amp cab lives in a humid environment the glue would set up very quickly. PS, "Hot Stuff" is another waterthin superglue formula that works extremely well on wood and wood products.