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Messages - jfetter

Pages: [1] 2 3
1
Tubes and Hybrids / Re: Noisy pots
« on: July 10, 2017, 05:26:21 PM »
maybe leave plate resistor alone and put a single Germaniun diode frm tube cathode to ground, no capacitor.. then solder a 1M resistor across the 4.7M 'grid leak' resistor.

that amp's control panel graphics are a beautiful period example.


2
Tubes and Hybrids / Re: My hybrid: jfet-Tube Sziklai-> classD pwr
« on: July 10, 2017, 05:06:49 PM »
it sounds just peachey. all day yesterday in hi-fi mode with r&b and blues. The stereo summer was too low for CD outputs but worked fine with dragonfly. changed from 680 to 2.2k.

you wont have much headroom using a single jfet front end. if using with the Sz pair then lots of headroom. guitar needs 5v PP input range without clipping. i would do the tube/fet front end.

the bias pot allows setting harmonic content to max 2nd, max 3rd or a mix. For hi-fi max 2nd or simply lowest THD.

3
Tubes and Hybrids / Re: My hybrid: jfet-Tube Sziklai-> classD pwr
« on: June 30, 2017, 05:37:00 PM »
Opps this is the jfet-mos front end. The above zip is tube-p-mos.


4
Tubes and Hybrids / My hybrid: jfet-Tube Sziklai-> classD pwr
« on: June 30, 2017, 05:28:17 PM »
Working on a new one now with some improvements, ie compressor so D amp never approaches clip.

 As-built zip attached.

-

5
Tubes and Hybrids / Re: My Hyrid Tube / TDA2050 amp
« on: June 30, 2017, 03:57:13 PM »
Super.
 :dbtu: :tu:

6
Tubes and Hybrids / Re: NAD!
« on: June 30, 2017, 03:52:25 PM »
Thought I'd put this here since its a tube amp.  :)
What makes you think that?  :o
Last time I checked, site name said "SS"  :o

its kinda funny, i've put up a lot of diy data on hybrids on another site and it gets no love , even the students get upset. if i put test plots and schematics in SS they cry, then if i put in Tube section they cry. Its hybrid and homeless. Nice to see a hybrid section here.

congrats on your amp find.

7
Schematics and Layouts / Re: Blackstar HT-1 schematic
« on: June 30, 2017, 03:09:50 PM »
The reverb looks like is using internal memory on a dspic.
Thanks for putting it up here. Nice to study other work.

8
Amplifier Discussion / Re: Class A solid state
« on: April 19, 2016, 06:22:57 AM »
i just finished the pre for you.
mounting in a test chassis now.

here is a link on other forum to it.

i like the amp you show. any fft etc available?
 :dbtu:
but i bite the bullet and go to symetrical power.

link:
http://www.diyaudio.com/forums/solid-state/290026-simple-discrete-sziklai-pre.html

9
Amplifier Discussion / Re: Class A solid state
« on: April 17, 2016, 08:30:04 PM »
I had in mind something like the JLH circuit i.e. single ended with active loading.


10
Schematics and Layouts / Re: enhanced orange squeezer type compressor
« on: February 12, 2014, 07:42:48 AM »
Excellent work, proud of you my man.

11
Preamps and Effects / Re: dspic-codec
« on: December 31, 2011, 10:58:40 AM »
Here is an example of a one knob super tone control. aka STONE control...
The control voltage is reduced to 64 discrete points and the tone MACs use the multipliers as "gain" for lo mid and hi. The center position gives an enormous scoop. It sounds very musical.
Adjustments can be made for LOW and HI too. What I like is the soldering iron is never plugged in.

volatile fractional STONE[64][3]={
    {Q15(0.570),  Q15(0.1),   Q15(0.235)},   //00
    {Q15(0.560),  Q15(0.1),   Q15(0.205)},   //01
    {Q15(0.545),  Q15(0.1),   Q15(0.195)},   //02
    {Q15(0.540),  Q15(0.1),   Q15(0.175)},   //03
    {Q15(0.535),  Q15(0.1),   Q15(0.165)},   //04
    {Q15(0.530),  Q15(0.1),   Q15(0.170)},   //05
    {Q15(0.525),  Q15(0.1),   Q15(0.175)},   //06
    {Q15(0.520),  Q15(0.1),   Q15(0.180)},   //07
    {Q15(0.515),  Q15(0.1),   Q15(0.185)},   //08
    {Q15(0.510),  Q15(0.1),   Q15(0.190)},   //09
    {Q15(0.505),  Q15(0.1),   Q15(0.195)},   //10
    {Q15(0.500),  Q15(0.1),   Q15(0.200)},   //11
    {Q15(0.495),  Q15(0.1),   Q15(0.205)},   //12
    {Q15(0.490),  Q15(0.1),   Q15(0.210)},   //13
    {Q15(0.485),  Q15(0.1),   Q15(0.215)},   //14
    {Q15(0.480),  Q15(0.1),   Q15(0.220)},   //15

    {Q15(0.475),  Q15(0.1),   Q15(0.225)},   //00
    {Q15(0.470),  Q15(0.1),   Q15(0.230)},   //01
    {Q15(0.465),  Q15(0.1),   Q15(0.235)},   //02
    {Q15(0.460),  Q15(0.1),   Q15(0.240)},   //03
    {Q15(0.455),  Q15(0.1),   Q15(0.245)},   //04
    {Q15(0.450),  Q15(0.1),   Q15(0.250)},   //05
    {Q15(0.445),  Q15(0.1),   Q15(0.255)},   //06
    {Q15(0.440),  Q15(0.1),   Q15(0.260)},   //07
    {Q15(0.435),  Q15(0.1),   Q15(0.265)},   //08
    {Q15(0.430),  Q15(0.1),   Q15(0.270)},   //09
    {Q15(0.425),  Q15(0.05),   Q15(0.275)},   //10
    {Q15(0.420),  Q15(0.05),   Q15(0.280)},   //11
    {Q15(0.415),  Q15(0.025),   Q15(0.285)},   //12
    {Q15(0.410),  Q15(0.025),   Q15(0.290)},   //13
    {Q15(0.405),  Q15(0.001),   Q15(0.295)},   //14
    {Q15(0.400),  Q15(0.001),   Q15(0.300)},   //15

    {Q15(0.395),  Q15(0.001),   Q15(0.305)},   //00 mid
    {Q15(0.390),  Q15(0.001),   Q15(0.310)},   //01
    {Q15(0.385),  Q15(0.025),   Q15(0.315)},   //02
    {Q15(0.380),  Q15(0.025),   Q15(0.320)},   //03
    {Q15(0.375),  Q15(0.05),   Q15(0.325)},   //04
    {Q15(0.370),  Q15(0.05),   Q15(0.330)},   //05
    {Q15(0.365),  Q15(0.1),   Q15(0.335)},   //06
    {Q15(0.360),  Q15(0.1),   Q15(0.340)},   //07
    {Q15(0.355),  Q15(0.1),   Q15(0.345)},   //08
    {Q15(0.350),  Q15(0.1),   Q15(0.350)},   //09
    {Q15(0.345),  Q15(0.1),   Q15(0.355)},   //10
    {Q15(0.340),  Q15(0.1),   Q15(0.360)},   //11
    {Q15(0.335),  Q15(0.1),   Q15(0.365)},   //12
    {Q15(0.330),  Q15(0.1),   Q15(0.370)},   //13
    {Q15(0.325),  Q15(0.1),   Q15(0.375)},   //14
    {Q15(0.320),  Q15(0.1),   Q15(0.380)},   //15

    {Q15(0.315),  Q15(0.1),   Q15(0.385)},   //00
    {Q15(0.310),  Q15(0.1),   Q15(0.390)},   //01
    {Q15(0.305),  Q15(0.1),   Q15(0.395)},   //02
    {Q15(0.300),  Q15(0.1),   Q15(0.400)},   //03
    {Q15(0.295),  Q15(0.1),   Q15(0.405)},   //04
    {Q15(0.290),  Q15(0.1),   Q15(0.410)},   //05
    {Q15(0.285),  Q15(0.1),   Q15(0.415)},   //06
    {Q15(0.280),  Q15(0.1),   Q15(0.420)},   //07
    {Q15(0.275),  Q15(0.1),   Q15(0.425)},   //08
    {Q15(0.270),  Q15(0.1),   Q15(0.430)},   //09
    {Q15(0.265),  Q15(0.1),   Q15(0.435)},   //10
    {Q15(0.260),  Q15(0.1),   Q15(0.440)},   //11
    {Q15(0.275),  Q15(0.1),   Q15(0.445)},   //12
    {Q15(0.285),  Q15(0.1),   Q15(0.460)},   //13
    {Q15(0.295),  Q15(0.1),   Q15(0.470)},   //14
    {Q15(0.325),  Q15(0.1),   Q15(0.480)}   //15    16 X 4=64
};

then in the DMA handler
// do the macs
        for(i=0; i<16;i++){
        ACMA = __builtin_clr();
        ACMA = __builtin_mac(ACMA,LOW, lowpassout, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
        ACMA = __builtin_mac(ACMA,MID, midpassout, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
        ACMA = __builtin_mac(ACMA,HI, hipassout, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
        sumadd = __builtin_sacr(ACMA,-3);
        }

12
Preamps and Effects / Re: dspic-codec
« on: December 30, 2011, 03:36:41 PM »
I!m bettin devaluation of usd very soon. Getting speakers will be a problem so a head is probably the way to go.

13
Preamps and Effects / Re: dspic-codec
« on: December 29, 2011, 09:24:39 PM »
Only plans are a pedal or head, maybe a combo. (I want to have something ready for production when the cheap imports go away). I will try to get a clip posted this weekend. Lost three days troubleshooting a nasty sound on one string. Turned out to be my headphone amp. I could not see it on scope so should have known. I'm now working on the WET-DRY mix having a lot of fun with it.
 Its using the dspic33fj256gp710, wolfson WM8731 and/or ti TLV320AIC codec. I have 4gb sd flash card for reverb tank. The flash should last several years with leveling(see microsoft "readyboost" http://blogs.msdn.com/b/tomarcher/archive/2006/04/14/576548.aspx ). DMA is utilized with the codec so processor has about 20% loading. The circuit itself is pretty simple. The codec takes care of anti-alias.
Schematic attached..
As mentioned I now do all work on OSX

14
Preamps and Effects / dspic-codec
« on: December 23, 2011, 12:50:48 PM »
I finally got the dspic preamp board done. Is any one else doing 16bit (_Q15) dsp?
It sounds great with no noise whatsoever. Running three filters now low,mid,hi.
Not much on the internet or from Microchip on pro-audio apps. Some of the old Analog Devices code works. The 16 bit works great for this app.

I need a good integer q15 reverb and a soft limiter.

This board is not a finished gadget. It is only for developing dsp code. Has six control voltages. Audio path is 100% digital.

15
Amplifier Discussion / Re: Class D Amp Recommendations?
« on: September 08, 2009, 10:15:20 AM »
I'm giving it a go with the TPA3106D1 and dsPIC33 for a combo unit. The dsp will let me do in software what I've been trying to accomplish in analog. The target is a smooth overdive with mild reverb. The dspic33fj128mc804 has a 16bit dac and 12 bit A2D. I'm planning on trying oversampling to get 14bit. We'll see.

Running on 24vdc I guess about 35w.

Strange no one is using this part.

 

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