Search found 951 matches

by phatt
18 Sep 2020, 12:49
Forum: Amplifiers
Topic: Suhr Reactive Load [schematic]
Replies: 35
Views: 3049

Re: Suhr Reactive Load [schematic]

Interesting quirk, Eons ago I built something similar. Sort of a loadbox come attenuator / line out. I rectified the signal to drive a fan and have never noticed the symptoms you describe. I used a full wave bridge and cap to store some energy,, maybe that helps? If you want I can pop the lid, Circu...
by phatt
12 Sep 2020, 02:10
Forum: DIY Stompbox designs
Topic: XR2206 Tremolo/Vibe/Leslie circuit
Replies: 7
Views: 1663

Re: XR2206 Tremolo/Vibe/Leslie circuit

LessLee update; Removed C12, C17 & R19. (Was no need for the Caps) Added R26 4k7 across VR2. Max resistance is now ~3k. Unlikely to find a 3k pot so a 10k with 4k7 gives a good balance. R23 up to 47k. (needed to reduce clock noise bleed through) Note Q1 supply must be taken before R25 otherwise it w...
by phatt
29 Aug 2020, 09:46
Forum: Amplifiers
Topic: Peavey amp
Replies: 33
Views: 1847

Re: Peavey amp

@ Soulsonic
Says it's a vss 20 head

@ george giblet
Thanks Good explanation,, I was confused about the relays and the way they are drawn.

@Jmpj48
Unless I've missed something,,,If you want you can just lift one end of C5 and the tone should work on both Clean and Drive.
Phil.
by phatt
29 Aug 2020, 02:29
Forum: Amplifiers
Topic: Peavey amp
Replies: 33
Views: 1847

Re: Peavey amp

I notice that R27 is 22k,, holy crap man that will just kill the ability of tone controls. The tone setup is HiZ but with 22k across the output your tone will be very restricted. :slap: If it were me I would lift one end of R27 just to see/hear if it improves the tone controls ability. It may have s...
by phatt
23 Aug 2020, 04:16
Forum: Pedal Debugging & Troubleshooting Support
Topic: 3 Band Baxandall Calculator
Replies: 2
Views: 243

Re: 3 Band Baxandall Calculator

Ideally you need to run a simulation to get an idea of what freq will change with different values. You may find that bass and treble values might need to change to get the tone shape you want. I'd guess there will be some trial and error to get it fine tuned. Sorry but I can't think of a quick fix....
by phatt
17 Aug 2020, 11:50
Forum: DIY Stompbox designs
Topic: XR2206 Tremolo/Vibe/Leslie circuit
Replies: 7
Views: 1663

Re: XR2206 Tremolo/Vibe/Leslie circuit

Hi Hot rats,, sorry been very busy, I believe this thing does a sum and difference trick,, still not sure of exactly how but I don't believe this chip has ever been used in this way. Sorry the schematic has gone but no matter as I've changed a few things. Update 17-8-20 1/ Resolved the tick,, thanks...
by phatt
22 Jul 2020, 01:14
Forum: Electric Guitar Rewiring
Topic: Reduce Wiring Noise: Avoid Magnets
Replies: 14
Views: 1409

Re: Reduce Wiring Noise: Avoid Magnets

Still got me stumped as to why makers still use unshielded cable for PU's.
Every time I open a fender and see the cloth wire I shake my head. :slap:
Phil.
by phatt
22 Jun 2020, 14:12
Forum: Amplifiers
Topic: How to improve tube amplifier tone by changing one part
Replies: 101
Views: 8066

Re: How to improve tube amplifier tone by changing one part

Maybe he just put the cap in backwards,,,,, :mrgreen:
Phil.
by phatt
19 Jun 2020, 12:49
Forum: Amplifiers
Topic: How to improve tube amplifier tone by changing one part
Replies: 101
Views: 8066

Re: How to improve tube amplifier tone by changing one part

Yesterday I had two Fender amplifiers in the workshop - a Hot Rod Deluxe and a Hot Rod Deville. I changed the first 22n capacitor after the input stage in both amps - used a TAD 22n mustard and the results were not subtle - I had the customer watching me for the Deville - first i played my strat in...
by phatt
12 May 2020, 12:27
Forum: Amplifiers
Topic: How to improve tube amplifier tone by changing one part
Replies: 101
Views: 8066

Re: How to improve tube amplifier tone by changing one part

I just listened to the video. I could hear differences between the different caps, though they were subtle. The first Vishay cap was the least good to my ears. I'll see about downloading the reaper files, because I'm always curious. I have found on many occasions, that simply replacing this first c...
by phatt
12 May 2020, 12:02
Forum: DIY Stompbox designs
Topic: light filter
Replies: 1
Views: 861

Re: light filter

:applause: Mate that is clever thinking. I love it :thumbsup
Phil.
by phatt
03 May 2020, 03:06
Forum: DIY Stompbox designs
Topic: XR2206 Tremolo/Vibe/Leslie circuit
Replies: 7
Views: 1663

Re: XR2206 Tremolo/Vibe/Leslie circuit

Just an update on the Schematic. Note a mistake on VR1, it needs to be 250k. Sorry :oops: You can go bigger for even slower speed but 250k delivers a good balance between Fast/Slow. Regards using a pedal; Unlike the old rack and pinion systems which deliver full 270deg rotation of the pot these chea...
by phatt
30 Apr 2020, 23:16
Forum: DIY Stompbox designs
Topic: XR2206 Tremolo/Vibe/Leslie circuit
Replies: 7
Views: 1663

Re: XR2206 Tremolo/Vibe/Leslie circuit

Hi Peter, thanks for the feedback. :thumbsup Hey Ben, Good to hear you like the effect. Yes you can run it on 18V as long as it is well regulated. My plugpak/wall wart is an old Cannon PSU and not well filtered so I used the reg chip to keep supply noise down. I will be designing another PCB when ti...
by phatt
27 Apr 2020, 11:43
Forum: DIY Stompbox designs
Topic: XR2206 Tremolo/Vibe/Leslie circuit
Replies: 7
Views: 1663

XR2206 Tremolo/Vibe/Leslie circuit

Revisiting a circuit I dreamed up years back and to the best of my knowledge this has not been done this way before so I thought folks might like to try it. This does a fairly good job of emulating a spinning speaker effect.It's based on a XR2206 function generator chip and with a few added parts ca...
by phatt
21 Apr 2020, 12:03
Forum: Pedal Debugging & Troubleshooting Support
Topic: Crybaby 95Q automatic, no sound with guitar but with finger
Replies: 8
Views: 711

Re: Crybaby 95Q automatic, no sound with guitar but with fin

I would treat that schematic as suspect. :slap: The Notes state to connect pin4 to VEE. Where the hell is VEE?? Pin 4 is usually VCC, or + input. there is also a VDD which goes nowhere?? I would go check you have it all wired up right. The last line on the Notes says "Circuit NOT Tested" so it's any...
by phatt
21 Mar 2020, 03:59
Forum: Amplifiers
Topic: I need help building a 4 button footswitch
Replies: 8
Views: 909

Re: I need help building a 4 button footswitch

I would like to build the footswitch shown in this schematic https://www.thetubestore.com/lib/thetubestore/schematics/Fender/Fender-Twin-Pro-Tube-Amp-Schematic.pdf I don't have any experience at all with something like this and i would like some guidance please. I presume that the unmarked diodes a...
by phatt
26 Feb 2020, 11:56
Forum: Amplifiers
Topic: using a 18volt transformer
Replies: 19
Views: 1624

Re: using a 18volt transformer

If the LM1875 is motor boating then it's passing signal which means it's working but unstable. Your PSU layout might be a problem. If you have long leads from Filter caps to LM1875 then that can cause issues. Judging by you first post showing the PSU schematic you wanted to use it's likely you have ...
by phatt
26 Feb 2020, 06:42
Forum: Amplifiers
Topic: using a 18volt transformer
Replies: 19
Views: 1624

Re: using a 18volt transformer

Was the LM1875 mounted on a heat sink? If not it will likely fail. Did you run it through a limiter at first power up? If not make a simple light bulb limiter it will save you from such disasters. google it,, easy to make up one. Also what schematic did you use? Maybe post it or link to it. Better s...
by phatt
21 Feb 2020, 10:41
Forum: Amplifiers
Topic: using a 18volt transformer
Replies: 19
Views: 1624

Re: using a 18volt transformer

Yes you can, there might be a little more voltage drop across the rectifier due the to higher rating but it won't be much.
Phil.
by phatt
21 Feb 2020, 07:35
Forum: Amplifiers
Topic: using a 18volt transformer
Replies: 19
Views: 1624

Re: using a 18volt transformer

All good,,
You can make the bridge with four 1N5404 if you want, they are a 400V, 3A device,,,
or if you want a BR64 is a 400V, 6A full wave bridge.
Or anything with similar specs will do the job.
Phil.