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Messages - joecool85

#1
Boss has expanded it's famous Katana line of amps to include a new headphone amp that fits easily into your pants pocket, enter the Katana:Go.  This is an interesting take on the headphone amp market and something that stands along with Fender's Mustang Micro amplifier in that it is a digital amplifier with multiple models, effects, and features.  One of the neat features with the Katana:Go is the app that you can use in Android or iOS to modify settings and saved presets.  You can also use this little guy as a USB C recording interface.

MSRP is $119 USD and they are available now.

https://www.musicradar.com/news/boss-katana-go-amp
#2
Quote from: monte on March 20, 2024, 09:12:51 AMThanks for the input!

I understand it likely not being best practice. I slowly I want to upgrade to a more 'grown-up' and proper set up, but for now I thought this could be cool for some experimentation. As long as I am not blowing anything up. ;D

I say go for it!
#3
Amplifier Discussion / Re: Watts vs Volume (db)
March 20, 2024, 09:12:42 AM
Quote from: JonnyDeth on March 20, 2024, 08:56:50 AMThe problem with this perspective is ultimately useable volume and wattage when you do a more thorough test of 100 Hz, 1 Khz, and 10 Khz with a sine wave. 1-watt @1 meter is using a 1 Khz sine wave, so it's dB rating isn't always the most reliable in terms of overall performance and projection.

Relative to this is the hardware distorting within a certain pitch range, as well as the speaker. You have to be prepared for potential crossover distortion, and many amps greatly lose efficiency in the lower frequencies at any volume. I agree that the speaker is one of the most important components regarding performance all across the board, and changing speakers may give you better performance and with a few more dB of useable volume, and that's a lot.

You must also take into realization that RMS/Peak wattage isn't telling you a whole lot in again, relationship to 100 Hz, 1 Khz and 10 Khz. Once you incorporate a speaker as the load on the circuit, you aren't dealing with watts, but the VAR of a resonant circuit. This is the precise point at which current and voltage meet in phase, and you get the most power transfer.
I've seen the most efficient systems built by using 100 Hz instead of 1 Khz exclusively to rate a speaker as well as the amp, and the VAR in equivalent effective wattage might be 10 watts compared to a 1 Khz sine wave resonating at 100 VAR(watts), or it might still be 100 VAR(watts) when using a 100 Hz sine wave, and that's phenomenal.

This is the final attribute where you also start to realize efficiency is overrated. I would rather have 100 effective watts of Class-A @ 100 Hz than Class-A/B or worse yet, Class-D. A really well-designed Class-A amp focused on VAR for 100 Hz resonance just as much as 1 Khz will be an animal not much can compete with. It's why some of these really old tube amps that weigh 150lbs will be just 30 or 40 watts, but they can compete with a modern Class-A/B or D that's full blast and rated 200.

Thanks for bringing up these points - all of them very valid and interesting!  While I am an advocate for solid state gear, I am by no means an expert and I love reading the in depth stuff some of our users here bring.  Thanks for joining the forum!
#4
Quote from: monte on March 20, 2024, 08:40:04 AMHi all,

I am quite new to amplifiers, I get the basics but have a little technical question. I just got an Orange Micro Dark hybrid (tube preamp/ SS power amp) that I am plugging into a 2x12 cab and that's quite nice for practicing at home. The Orange MD has an effects loop and I had an idea of splitting the loop signal into wet/dry and sending the wet (mostly for delay) into another practice amp I have, a Roland Cube 20 (an 80s, orange version one) and dry into the Orange power amp (as usual). The thing is, the Roland doesn't have an effects loop, so I would have to send the wet into the amps line in. Is this at all doable? I figure I'd ask before I blow up my Roland, which I like quite a lot.

And in general, is it ok to plug an effects loop out into the line in of another amp (tube or solid state)? From what I understand, the preamp stage of an amp functions in a similar way than an OD/Preamp pedal, so that should be fine?

Any thoughts/concerns/ideas are welcome!

Thank you so much!

While some may not consider it best practice, in reality it shouldn't be a problem at all.  I would do this without hesitation.  The only thing to not do is to hook up the speaker output to the guitar input on another amplifier...that is a very bad idea.
#5
Rock on!  I remember looking at Crate amps when I was a beginning guitarist almost 25 years ago.  I always thought they looked cool.  Maybe not everyone's cup of tea, but they sure do get loud!
#7
Quote from: fazeka on March 19, 2024, 05:11:11 PMThanks Tessieviking for this!

FWIW/FYR: here's the broken one that came out of the amp:



How's this through-hole axial look as a replacement?

Would like a stud mount like the original but me thinks these went the way of the dinosaurs...  :o

Looks good to me!  I think you're right about stud mount, I don't think I've ever seen those for sale in the 20+ years I've been doing this.
#8
There was a whole lot of stuff at NAMM, but most of it had to due with guitars, tube amps, or digital amps.  We did get a little bit focused on solid state gear though!

Blackstar has updated their ID:Core amps with the new v4 series. The new updates include: USB C connection, power reduction feature, and "other minor improvements to models".  While the power reduction is nice, the biggest thing for me here is the USB C hookup - finally!
 
Pricing is 219, 249, and 279 British pounds for the ID:Core 10, 20, and 40 respectively.

https://www.gearnews.com/blackstar-idcore-v4-revamped-and-now-with-new-1-watt-mode/

-----

Vox has updated their AmPlug series with the new AmPlug 3 range of headphone amps.  These new Amplug models have minor enhancements to each model and Vox has also adjusted the on-board effects to take advantage of "wide stereo" sound.

Pricing looks to be same as before, $49.99 USD.

https://www.gearnews.com/vox-amplug-3-7-new-revamped-headphone-amps/
#9
The Newcomer's Forum / Re: LA4282 in BTL bridge mode?
February 27, 2024, 02:46:44 PM
Quote from: Maddus on February 26, 2024, 03:24:54 AMIs it bad for the chip when only one channel is mostly used? So my idea would be to hook up one channel to an internal speaker and the other to an extension speaker jack.

I think that is a fantastic idea.
#10
The Newcomer's Forum / Re: LA4282 in BTL bridge mode?
February 19, 2024, 02:53:34 PM
Quote from: Maddus on February 15, 2024, 03:10:24 AMI was given a LA4282 from my fathers workshop (he repaired lots of TVs in the 90s).
To use this for my guitar projects, I would like to know if I can bridge this like a LA4440 for example, and what external circuitry is needed.
The LA4282 already has input and feedback resistors for a gain of 101 integrated.


Datasheets:

LA4282:
https://www.mouser.de/datasheet/2/308/1/LA4282_D-2314539.pdf

LA4440:
https://www.electroschematics.com/wp-content/uploads/2012/07/la4440-datasheet.pdf

You can actually get a LOT of volume out of 10 watts.  I would consider using the chip as-is and hook it up to a quality 12" guitar speaker.
#11
Did you reverse engineer the amp and make this schematic?  If not, where was it obtained?
#12
Amplifier Discussion / Mobile surge and RF protection
January 25, 2024, 02:30:54 PM
I had a spare Isoblok I wasn't using, so I removed the built in plug and put in an IEC jack.
#13
Quote from: mccutter on January 14, 2024, 05:40:53 AMThank you phatt, Only have to find a old bulb  ;) and not led  :) !
And thank you  g1 , I let you know the progress !


If you are having trouble finding an incandescent bulb for this, try looking at heat lamps.  You'll pay more, but they are readily available.  If you don't see them in a hardware store, try a pet store and get a reptile heating lamp.  As long as it glows red, it's the right type (they have some ceramic ones that don't emit any light and wouldn't work the same).

Good luck!
#14
Amplifier Discussion / Re: Tech 21 Trademark 60 Noise
January 22, 2024, 01:54:49 PM
Quote from: Lobsterjoe on January 10, 2024, 02:47:17 PMJust got an '06 Trademark 60.  At power-on, there are continuous popping and whooshing noises.  Consistently, it goes away after about six minutes.
Power cycle and the noise returns but then lasts less than a minute; unless the amp's been powered for an hour or more-then it's fine after restart.
All other functions work and amp sound normal except for addition of noise.
If I plug guitar into the effects return, the noise stops and guitar sound is fine.
Cleaned all the jacks, visually inspected PC board, jumpered the FX loop jacks (no effect on noise).
Channels settings, boost level and reverb level don't affect the noise level, but master EQ does. The character of the noise doesn't change-just how loud it is proportionate to the EQ cut or boost.
Tech 21 was responsive to my inquiry and said they haven't seen this before. Suggested I send it in. Being in California, the round trip shipping even for chassis only will be almost as much as the bench charge. Reminder: other than switches and some caps/IC's, most of the components are SMT. Comments welcome.

Given that the noise is modified by the tone stack, that means that it is happening before this point in the circuit.  Starting there (at the tone stack), working your way backwards towards the input jack.  Something between here and there is either fried, or has a cold solder.  Odds are it is a cold solder.  Careful inspection of the potentiometers as well as any caps and ICs that are through hole components in this area (between input jack and tone stack) and I think you'll find the issue.

You can also share close up pictures of the board and we'll see if we can help.
#15
Quote from: Maddus on January 12, 2024, 04:22:45 AMOk, thanks. Would I also hear that oscillations if they happen?
I hear some background fuzz underlying the notes.

Typically opamp oscillation is above the hearing spectrum, nothing you would be able to reproduce through a speaker or hear.