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Topics - syndromet

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1
Amplifier Discussion / Pedal into TPA3116, impedance problems?
« on: August 14, 2019, 02:40:56 AM »
Hi guys, long time no see!

I've been playing around with tube stuff for the last few years, but I figured it was time to have some fun with SS again. I'm planning a pedal sized amp based on the TPA3116 driven by a MI Crunchbox. I'm using one of these boards for the power amp:
https://www.aliexpress.com/item/32811325655.html?spm=a2g0s.9042311.0.0.27424c4dHDFca6

When I hook the pedal straight into the power amp board I get sound, and it's nice and loud. I can hear the potensial, but the sound gets way to bassy. The crunchbox is usually a pretty trbley pedal, but when hooked up to the TPA3116 I need to turn the tone controll all the way up, and I still feel I miss a little too much treble.

The pedal has an output impedance at around 1 Kohm, and the amp board has an input imedance of 10 Kohm. Ofcource, the pedal is made to see impedances a lot higher than this, and I suspect that is why I get a lot of treble loss. What is the best way to fix this? I can't change the input impedance on the power amp without affecting the gain of the amplifier, right? And since the output of the pedal is 1 Kohm, I don't really see how a buffer can make things better?

Any Ideas to how I can make this combo work? I can already hear that it has a lot of potential..

2
Amplifier Discussion / I think I want a Pignose.
« on: December 04, 2012, 02:32:21 PM »
Hi, guys! It's been a while since last I contributed with anything here, as I've been busy getting kids, building a house, building a career and playing with tubes. I finally have some spare time again, so my interest in building guitar related gadgets have come back. I'm currently building a Hiwatt DR504, fixing an Ampeg SVT 6 pro and producing a small run of guitar pedals for sale.  :dbtu:

After seeing this video, I think I'm falling in love with the pignose 7-100, and I'd love to build a high quality version of this wonderful amp. I see the amp already have been discussed on this forum a few times before, but I can't find any info on the transformers used in it. I was wondering if any of you guys who actually understand this kind of stuff knew what impedances the transformers are? If not, I'm hoping some of the experts here can make an educated guess.

I'm guessing the transformer between the preamp and the power section is has a 1:1 ratio, and that it's function is purely to isolate the two stages from each other. When it comes to the transformer on the output section, I  guess it's there to match the impedance to the speaker load. What would be the primary impedance on something like this? Is there anyway to calculate this stuff?

Pignose video:
http://www.youtube.com/watch?v=_q0nImsfMvE

Schematic:
http://music-electronics-forum.com/attachments/2913d1218923726-pignose-model-7-100.gif

It's good to be back.
Thanks in advance!

3
Tubes and Hybrids / First tube amp.
« on: December 03, 2008, 03:13:06 AM »
Not exactly a hybrid, but I like to show off.  ;) Here is my first venture into high-voltage tube stuff. High Octane from AX84.

Pretty happy with the externals. Got to find some miniature chickenheads, though.


Messy, as always.....

4
The Newcomer's Forum / Reposting my encyclopedalia
« on: February 27, 2008, 06:20:06 AM »
I have had quite a few requests for this lately, so I thought I should repost it her. Quite a usefull tool for beginners and transistor swappers....
It is still a work in progress, and any tips on other stuff to be in here is welcome. I'm working on transelating the mm drill sizes to inches for you weird Americans.
Admins, feel free to add a link to the FAQ if you feel like it.
Encyclopedalia

5
Amplifier Discussion / Good source for transformers?
« on: September 12, 2007, 05:06:12 AM »
I'm looking for a 2x24V secondary, 230V Pirmary transformer with a rating of 300VA, and I can't seem to find anyone else than elfa.se who will ship internationaly. On elfa, the trafo costs around 100$ without shipping, wich I find a little to expensive. Anyone know of a good source for cheap trafos? I used Apexjr.com the last time, and they were great, but I don't think they have what I'm looking for this time. The trafo will be used for a 41hz.com AMP5.

6
Amplifier Discussion / Using car HiFi amps
« on: June 18, 2007, 10:00:05 AM »
Would it be possible to use something like this with guitar?


Specs
Distortion:                            <0,08 % THD at 2ohm
                                          <0,1 % THD at 4ohm
Frequenzies                           20 Hz -20kHz +/-0,5dB
Dampening                            >95dB
bass boost                            +8dB, centered around 45hZ
Input impedance                     20kOhm
Input sensitivity                      150mV - 8V
Output impedance                   Stereo: 2-8 ohm
                                           Bridged: 4-8 ohm
Dc input                                10-16 V


RMS                                     2 x 50W at 4 ohm and 14,4 V
                                           2 x 75W at 2 ohm and 14,4 V
                                           150W bridged at 4 ohm
Max power                             200w bridged at 4 ohm
Fuse                                     20A


Protected aginst shorts, to high dc and overheating.

Looks like a typical poweramp to me, and the chassis is made of tinned aluminium. Would it be suiteable with guitar ,bridged for mono and high power with the right preamp?

7
I have sent my girlfriend and daughter home to my mother in law for about a week, wich has given me time to finnish of my stereo LM 1875 amp. I'we done all the offboard wiring now, and everything should be ok. I'we added a volume pot at the input, and it works ok when it comes to control volume. However, when I turn it down, my chips start to clip, like it does when it's getting to hot. Sort of like a hard tremolo. when playing above half the volume, I don't have this problem, and I don't have it when I use the volume controll on my Behringer gdi21, wich I use as a preamp.

The amp sound fantastic, anyway, but it would be great to be able to controll the volume, as it is plenty loud. Could it be low freequenzy oscilaion? Ground loops?

Some pics, just for fun. The pics are taken with a cell phone-camera, so this hing looks a lot better in real life.


Gutshot. Wiring looks messy here, but is in fact pretty neat.


Another gut shot


The fan and led controlling circuit


The volume pot in question


The input and outputs


Power switch, fan and led


8
Amplifier Discussion / Drill sizes
« on: May 09, 2007, 09:38:28 AM »
Might be usefull here too....
Drill sizes for common components, like leds, pots etc....
www.syndromet.com/drill.doc

9
I lost one of those little plastic isolators that you use to isolate the chip from the chassis when you mount it, and I don't have anyone in spear. Is there anything else that can be used? Anyone have any good ideas?

10
Schematics and Layouts / TDA2005 amp
« on: March 16, 2007, 03:55:39 AM »
http://www.circuitsonline.net/forum/view/36929/2/tda2005+layout

A little down on this page you'll find schematic and layout for a TDA2005 amp.
Look on the middle of the page for where it says :


"Een warme avond verder:
Schema in pdf
Layout in pdf
Componentenopstelling in pdf
Componentenlijstje
Schema/layout voor Ulticap/Ultiboard in zip"

11
Amplifier Discussion / I'm about to order my transformer
« on: March 12, 2007, 03:36:14 PM »
Just to be absoloutly sure, I wanna check with you guys (once again...) that I'm ordering the right transformator for my stereo LM1875 kit. Don't want to buy a trafo for $100, and find it's not suiteable for the job.

This is what I'm looking at: http://www.elfa.se/pdf/56/05612569.pdf
Would this be good for my purpose?

Looking at the prices, I see that transformersare way cheaper over at parts express than here in Norway. Unfortunatly they wanted to charge me $79 for shipping it via USP Express. That got me thinking about ordering it to one of you guys, and having you to ship it with USPS to me for way cheaper. If anyone feel like helping me out with this, please let me know.

12
Amplifier Discussion / Has anyone seen this?
« on: February 05, 2007, 12:28:11 PM »

13
Amplifier Discussion / Class T-amps
« on: January 04, 2007, 08:37:51 AM »
Have any of you guys tried a class-t amp for guitar. I got my SI T-amp from think geek today, and it gets great rewievs from the hifi-people. it cost 29$, wich is next to nothing. The circuit seems super simple, it recuires 12 v dc, and the chip don't need heatsinking. It is based on a Tripat 2024, wich is awaileable from PartExpress. Anyone tried one of theese with guitar? Looks like an easy buid, or an easy rehouse if you buy the SI version.

14
Amplifier Discussion / RobertT.....
« on: November 28, 2006, 06:15:21 AM »
Seems like Harrison Ford from diystompboxes has found this forum too. I say one of you admins ban RobertT emediatly.

15
Amplifier Discussion / Pictures
« on: November 19, 2006, 09:52:46 AM »
We need a picture-thread for the amps, too! Post your DIY-amps here!!
My little gem:


My stereo ruby:

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