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Messages - joecool85

#1
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/

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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/
#2
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.
#3
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.
#4
Did you reverse engineer the amp and make this schematic?  If not, where was it obtained?
#5
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.
#6
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!
#7
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.
#8
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.
#9
Quote from: WimWalther on November 03, 2023, 11:30:08 PMHi folks,

Is there any point in changing out the 4558s in a (first model, mid-1983) Peavey KB 300?

Is there much of anything to be gained by this? The amp works fine, though it's maybe a bit noisier than I'd wish.

Thanks!

What are you going to swap in place of the old 4558s?  TL072?  For what it's worth, those old 4558's are considered magic by many.  They aren't though, they just have an awful slew rate and are kind of noisy.  The DO happen to work well for electric guitar though.
#10
Quote from: saturated on November 02, 2023, 07:29:17 PMall i know or think is zener diodes are kind of like backwards diodes...idk 

 ::)


Almost.  Standard diodes only allow current in one direction, zeners can flow in both directions.  Zeners will operate similar to a standard diode in forward mode, but in reverse at breakdown voltage they allow current without letting out the magic smoke.
#11
Quote from: WimWalther on October 28, 2023, 01:15:24 AMHowdy,

I just picked up a KB 300 for a song. The unit is really nice, but the controls are dirty and the cord jacket is cracked just outside of the Heyco grommet. ETA: Cord is fixed.. Had to cut off 1" and re-set the cord in the grommet.

So the chassis needs to come out but I'm not having much luck. I found 4 screws on top (chrome strips) and 4 more in the back that secure the chassis to the case. Also unplugged the speakers & reverb tank.

The chassis can be shifted a bit, but won't slide out the rear.. what am I missing? More screws somewhere? ETA: Got it. Was hanging up on the edge of the chassis.

Also.. this is the early version (no XLR input), built in mid-1983. It doesn't have the pair of 5W resistors on the back of the tweeter horn. Should these be added, for safety? Do you know the correct value(s)?

Thanks!

Regarding the tweeter resistor: for safety, no I do not think it is necessary.  I would need a schematic to confirm this though.  Typically those resistors help to shape what frequencies are going to the tweeter.  If you like how it sounds now, you can probably leave it as-is.
#12
With Axe FX being around for 17 years, Fender has finally decided it's time for them to jump into the arena.  Being that Fender is a very traditional company, this isn't very surprising.  That said, this isn't just a little toe dipping into the water, this is a big SPLASH!  The Tone Master Pro is a full-on modeler featuring an 8 core processor, over 100 amps models, 60 second stereo looper, 7 inch digital display, and built in 4x4 USB audio interface.

MSRP is $1,699.99 USD.  With this price, it is definitely for the gigging musician rather than hobbyist.

Fender has also released two full response self-powered cabs that are made to pair to this.  The Tone Master FR-10 and FR-12, both with 1,000w of class D power.

https://www.gearnews.com/fender-tone-master-pro-floor-revealed-a-new-helix-killer/
#13
Quote from: saturated on October 10, 2023, 11:49:46 PMI am really enjoying this set up

very much so

but apparently this Crate Amp was neglected and not played enough and in need of some love

because this slide switch has been cutting in and out and off and on...but getting better with some exercise

You cannot view this attachment.



It probably needs to be cleaned.  Personally I'm not a fan of slide switches at all, mostly for this reason.
#14
Amplifier Discussion / Re: Modding an Ampeg SS70
September 27, 2023, 09:42:05 PM
Quote from: FleshOnGear on September 23, 2023, 05:47:05 PMThe are some big positives for this amp. The cabinet is sturdy. Even stock the clipping circuit is sufficiently tube-like in tone. And, these are relatively cheap on the used market. Just a few tweaks and I got a great, dynamic metal tone.

Rock and roll!
#15
Starting to look good!