Another MYSTERY BOX arrives | Rift Weekly Update |
Вставка
- Опубліковано 6 жов 2024
- PLEASE NOTE: This is not a tech channel, but simply a show-and-tell. It is not designed to give advice and support on vacuum tube amplifiers but to show what I get up to each week in the workshop.
I deliberately keep tech talk to a minimum, or at least to a point where it’s understandable to the casual viewer. There are other channels more suited to that level of detail.
I do not do reviews, either paid or unpaid. My opinions are entirely my own and do not represent those of others.
All comments are welcome but those deemed unhelpful, rude, inappropriate, or unsavoury will be reviewed and possibly censored.
---------------------------------------------------------------------------------------------
-
---------------------------------------------------------------------------------------------
EQUIPMENT I USE
Wire Strippers - uk.rs-online.c...
Knipex Snips - uk.rs-online.c...
Oscilloscope - uk.rs-online.c...
Signal Generator - uk.rs-online.c...
Soldering Station - uk.rs-online.c...
Chisel Tips - uk.rs-online.c...
Great to see the problem solving in action, but I particularly liked the board loading montage with the Bossa-Nova tune, reminded me of watching 'Paint with Nancy' when I was a kid, so thanks for that, I think? 🤣🤣🤣
I enjoyed the time-lapse board population, noticing that you work only from the top, and solder as you go. Have you found that hooking the leads around the back of the eyelet is not necessary? Thanks, great video as usual!
Hi, would you mind expanding on why it's best to keep a jumper in an effects loop when it's not in use please? Not heard that before but interested to understand/learn! Many thanks!
If it helps, had an old Selmer practice amp with just vol and tone. As I turned up the Tone the output volume decreased till zero output on full. It had a .1uf cap on the back of the tone control which looked clean and new but I replaced it with a "used" jensen cap and it worked , sounded a bit more assertive and hard but did the job. Had to have a look inside the faulty cap so I cracked it open , it was like solid rock inside a bit like dry coal . It was definitely a replacement that got salvaged from a TV set? Great video, thanks and have a good Sunday.
The tone control is just a cut on the AC10 isn't it? Wired in reverse, or you're looking at it in reverse? Vox did that all the time, my AC10SRT trem depth control is wired backwards for example. No clue on the output issue, but excited to learn about what it is. You said it not only tests low, but sounds really low output? 2w, so basically no balls whatsover? My AC10 twin (same amp) is an angry little thing, punches way above it's weight people are always surprised by how loud it is.
2v output, so roughly 0.5w!
I thought the same, that old VOX tone controls work backwards. I'm not handling vintage amps every day though, so I could be wrong.
Mitch worked for Korg/Marshall /Vox for 32 years. He left in 2010. We’ve been friends since 1989! Great guy!
Do you recall the voltage reading on the heaters of the JCM900? I’ve seen one with 7.3 or so
Very perplexing on the low output..as all voltages are correct, DC and signal voltages..i would,like you, suspect faulty O/P TX, with shorted secondary, but as you subbed a different T/X..am a bit stumped. Will look forward to you locating the problem..
Another very interesting video. I didn’t know that the Park brand name had changed hands, I was still under the impression that it was a Marshall brand. It looks to be a very well made amplifier, shame about the underrated capacitors though and as you mentioned the 5Y3 wasn’t really up to the job, the GZ34 is a much better choice. I’m very interested in learning what the cause of the low output of the AC10 is, I would have suspected the output transformer but you ruled that out by substituting it finding no change in output level. The under sized can capacitor is a bit of a pain but the problem with it being undersized is probably easier solved than it being too large. I think that if I had that problem I’d try the heat shrink, , if carefully cut it would be almost invisible under the clamp.
Hi Chris. Can you please show how you’ve connected the oscilloscope to test the output.
Other channels I’ve watched have cautioned against connecting one without using an isolation transformer to prevent too much current flow from damaging the oscilloscope.
Thanks for the videos.
There isn't any current flow to speak of into the 'scope. Probes have a 1 M ohm resistance and act as voltage sensors between tip and ground connections and 'scopes can be rated up to hundreds of volts. Current doesnt flow in the probe connection. If it did then there would be a potential divider between the circuit and the probe and that would defeat the purpose.
On the Park, how are they only getting 18W using EL34, 6L6 or KT66's? Do they have it biased extremely cold? If so wouldn't that also be true when using 6V6's, since it appears to use the same cathode resistors, unless there is something else in the circuit that changes the voltage when different tubes are used.
woot!! Any Rift day is a good day.. however your voice over was definitely sponsored by Professor Stanley Unwin, Lovely!
Construction on the Park is weak
Someone like Colby should have realized this.