Something I have been working on for the last two months - A 15W combo amp with 8" Jensen speaker and footswitchable boost and reverb.
Amp cabinet :
(http://img259.imagevenue.com/loc415/th_69863_Howler_01_2_122_415lo.jpg) (http://img259.imagevenue.com/img.php?image=69863_Howler_01_2_122_415lo.jpg) (http://img125.imagevenue.com/loc541/th_69872_Howler_02_2_122_541lo.jpg) (http://img125.imagevenue.com/img.php?image=69872_Howler_02_2_122_541lo.jpg)
Output stage, Power Supply & Transformer, Mains PCB, Speaker & Line Out PCB :
(http://img43.imagevenue.com/loc223/th_69873_Howler_03_2_122_223lo.jpg) (http://img43.imagevenue.com/img.php?image=69873_Howler_03_2_122_223lo.jpg) (http://img175.imagevenue.com/loc111/th_69876_Howler_05_2_122_111lo.jpg) (http://img175.imagevenue.com/img.php?image=69876_Howler_05_2_122_111lo.jpg) (http://img120.imagevenue.com/loc586/th_69878_Howler_06_2_122_586lo.jpg) (http://img120.imagevenue.com/img.php?image=69878_Howler_06_2_122_586lo.jpg) (http://img141.imagevenue.com/loc464/th_69874_Howler_04_2_122_464lo.jpg) (http://img141.imagevenue.com/img.php?image=69874_Howler_04_2_122_464lo.jpg)
I shall keep you informed of progress.
Congratulations.
Very nice, very professional.
Please post the preamp, when you have it.
Juan Manuel Fahey.
Quote from: J M Fahey on October 12, 2009, 04:08:08 PM
Congratulations.
Very nice, very professional.
Please post the preamp, when you have it.
Juan Manuel Fahey.
Yeah what he said.
Info on the cabinet? Did you build it or buy it. Looks real nice! :tu:
Looks good. Solid and professional. Must have taken plenty of time to plan that all out so that everything fits so perfectly.
You get chip points for that one, looks like a very well built amp.
Any sound clips for us to hear? What'd you use for preamp/poweramp circuits?
First, I'd like to thank you all for the kind words - very encouraging. In the meantime I managed to finish the chassis (1mm thick pressed steel, black coated). The partially populated chassis could be seen in the pictures below :
Top, rear & front :
(http://img158.imagevenue.com/loc136/th_69880_Howler_07_2_122_136lo.jpg) (http://img158.imagevenue.com/img.php?image=69880_Howler_07_2_122_136lo.jpg) (http://img20.imagevenue.com/loc130/th_69886_Howler_08_2_122_130lo.jpg) (http://img20.imagevenue.com/img.php?image=69886_Howler_08_2_122_130lo.jpg) (http://img207.imagevenue.com/loc371/th_69888_Howler_09_2_122_371lo.jpg) (http://img207.imagevenue.com/img.php?image=69888_Howler_09_2_122_371lo.jpg)
From left to right - Input jack, Drive, Volume, Normal volume, Treble, Bass, Middle shift switch (tone voicing), Reverb, Footswitch jack (with panel switch for Normal/Overdrive mode), LED indicator and power switch. There are also a fuse holder, speaker and line out jacks on the rear panel. Still have to "win another hard battle" - the preamp. As for now, I'm satisfied with the reverb circuit, tone stack and the normal/overdrive switching section.
QuoteInfo on the cabinet? Did you build it or buy it. Looks real nice!
Cabinet was built by a very good frend of mine (he did almost all of the woodwork) and me. It is constructed of 18mm thick birch plywood with finger-jointed sides.
QuoteMust have taken plenty of time to plan that all out so that everything fits so perfectly.
You are very, very much right about that.
Next time - Powering the "semi-amp", measuring and output waveforms ...
Quote from: Mangas on October 14, 2009, 03:09:47 PM
First, I'd like to thank you all for the kind words - very encouraging. In the meantime I managed to finish the chassis (1mm thick pressed steel, black coated). The partially populated chassis could be seen in the pictures below :
Top, rear & front :
(http://img158.imagevenue.com/loc136/th_69880_Howler_07_2_122_136lo.jpg) (http://img158.imagevenue.com/img.php?image=69880_Howler_07_2_122_136lo.jpg) (http://img20.imagevenue.com/loc130/th_69886_Howler_08_2_122_130lo.jpg) (http://img20.imagevenue.com/img.php?image=69886_Howler_08_2_122_130lo.jpg) (http://img207.imagevenue.com/loc371/th_69888_Howler_09_2_122_371lo.jpg) (http://img207.imagevenue.com/img.php?image=69888_Howler_09_2_122_371lo.jpg)
From left to right - Input jack, Drive, Volume, Normal volume, Treble, Bass, Middle shift switch (tone voicing), Reverb, Footswitch jack (with panel switch for Normal/Overdrive mode), LED indicator and power switch. There are also a fuse holder, speaker and line out jacks on the rear panel. Still have to "win another hard battle" - the preamp. As for now, I'm satisfied with the reverb circuit, tone stack and the normal/overdrive switching section.
QuoteInfo on the cabinet? Did you build it or buy it. Looks real nice!
Cabinet was built by a very good frend of mine (he did almost all of the woodwork) and me. It is constructed of 18mm thick birch plywood with finger-jointed sides.
QuoteMust have taken plenty of time to plan that all out so that everything fits so perfectly.
You are very, very much right about that.
Next time - Powering the "semi-amp", measuring and output waveforms ...
You'll have to enter this one into the next SSGuitar contest. I look forward to any schematics/circuit ideas you want to share as well as sound clips.
The output stage is powered, finally. The first impression is that the amp is very quiet. You can hear a low level hum only if you put your ear up against the speaker. DC operating points are within +/- 5% of calculated and simulated values 0:). Quiescent current is very stable (bias servo is doing its job correctly).
The test equipment used :
(http://img154.imagevenue.com/loc538/th_24185_Howler_16_2_122_538lo.jpg) (http://img154.imagevenue.com/img.php?image=24185_Howler_16_2_122_538lo.jpg)
With 1Veff/1kHz input signal, the amp produces 11.37 Veff output into 8 ohms dummy load or 16Watts RMS (A little more than I aimed for).
(http://img16.imagevenue.com/loc208/th_24187_Output_power_122_208lo.jpg) (http://img16.imagevenue.com/img.php?image=24187_Output_power_122_208lo.jpg)
Temperatures (heatsink and transistors) after one hour of working on the verge of clipping could be seen in the pictures below :
(http://img214.imagevenue.com/loc585/th_24184_Full_output_122_585lo.jpg) (http://img214.imagevenue.com/img.php?image=24184_Full_output_122_585lo.jpg)
Temperatures (heatsink and transistors) after one hour of severe clipping could be seen in the pictures below :
(http://img262.imagevenue.com/loc211/th_24182_Clipping_122_211lo.jpg) (http://img262.imagevenue.com/img.php?image=24182_Clipping_122_211lo.jpg)
Output waveforms :
(http://img190.imagevenue.com/loc240/th_24177_Output_waveforms_122_240lo.jpg) (http://img190.imagevenue.com/img.php?image=24177_Output_waveforms_122_240lo.jpg)
Although the amp uses mixed mode feedback, output waveforms were recorded with a classic voltage feedback. The reasons are ... Shall we say, more obvious stability test results. I didn't upload a picture of 10kHz square output wave also, because the input signal was fed throughout bandpass filter at the amp's input (low pass : -3dB @ 45kHz). After all, this is a guitar amp not a Hi-Fi one. ;)
P.S. : Sound clips will be uploaded soon.
Excellent information, very interesting.
If you don't mind me asking, what is your background? Are you an engineer or something?
QuoteIf you don't mind me asking, what is your background? Are you an engineer or something?
Yes, I have a master's degree in electrical engineering. My current employment doesn't include anything "audio-based". I'm dealing with SCADA (Supervisory Control And Data Acquisition) systems implemented in electrical substations. Briefly - Substations are equipped with microprocessor relays (for protection and control) and an RTU (Remote Terminal Unit) which processes all of the necessary signals and enables remote supervision from the supervision center. My department's job is to administer and maintain the whole SCADA system - both software and hardware.
I've been playing a guitar for over 20 years and soon after I became a music addict, "the analog audio electronics virus" infected me too. Haven't been cured since. :o :duh You can see the consequences clearly.
Didn't post anything for days, sorry. I have a very busy schedule. Last week ... :grr. I'll try to upload sound clips and further information concerning the amp building process as soon as possible.
Quote from: Mangas on October 23, 2009, 04:52:22 PM
QuoteIf you don't mind me asking, what is your background? Are you an engineer or something?
Yes, I have a master's degree in electrical engineering. My current employment doesn't include anything "audio-based". I'm dealing with SCADA (Supervisory Control And Data Acquisition) systems implemented in electrical substations. Briefly - Substations are equipped with microprocessor relays (for protection and control) and an RTU (Remote Terminal Unit) which processes all of the necessary signals and enables remote supervision from the supervision center. My department's job is to administer and maintain the whole SCADA system - both software and hardware.
I've been playing a guitar for over 20 years and soon after I became a music addict, "the analog audio electronics virus" infected me too. Haven't been cured since. :o :duh You can see the consequences clearly.
Didn't post anything for days, sorry. I have a very busy schedule. Last week ... :grr. I'll try to upload sound clips and further information concerning the amp building process as soon as possible.
Quite impressive background.
Glad to have you aboard, post when you can as it is very enjoyable seeing your projects. :tu:
It's been awhile since my last post. I've been very "productive" last week so the preamp "test rig" is almost finished (more about that next time). Meanwhile, I managed to record two audio clips (as promised :)) for you to hear the sound of assembled power amp.
DigiTech RP300 modeling guitar processor was used as a preamp (no effects and simulations - only equalizer (bass, middle, treble) and reverb added). The pedal itself doesn't have high enough output to drive the amp properly :'( so "the punch" is less than it should be with adequate preamp.
The setup used was :
Fender Stratocaster (neck and middle pickup individually) - RP300 - Power amp with built in speaker - Mic - Behringer mixer with tone controls flat - PC
http://sharebee.com/4c02458c - Neck position pickup (clean)
http://sharebee.com/6ba66253 - Middle position pickup (clean)
Didn't record overdriven tones because I wanted to hear harmonic content of the amp itself. All comments are welcome.
Quote from: Mangas on October 30, 2009, 10:08:09 AM
It's been awhile since my last post. I've been very "productive" last week so the preamp "test rig" is almost finished (more about that next time). Meanwhile, I managed to record two audio clips (as promised :)) for you to hear the sound of assembled power amp.
DigiTech RP300 modeling guitar processor was used as a preamp (no effects and simulations - only equalizer (bass, middle, treble) and reverb added). The pedal itself doesn't have high enough output to drive the amp properly :'( so "the punch" is less than it should be with adequate preamp.
The setup used was :
Fender Stratocaster (neck and middle pickup individually) - RP300 - Power amp with built in speaker - Mic - Behringer mixer with tone controls flat - PC
http://sharebee.com/4c02458c - Neck position pickup (clean)
http://sharebee.com/6ba66253 - Middle position pickup (clean)
Didn't record overdriven tones because I wanted to hear harmonic content of the amp itself. All comments are welcome.
My computer at work didn't want to be fun and let me play the clips, thanks for posting an update though.
The Pre amp "test rig" is finished. All necessary modules (gain stages (op amp based and fully discrete), buffers, summers, clippers, ...) are assembled and tested. Everything is ready for the final tweaking (at last).
"The motherboard" :
(http://img229.imagevenue.com/loc210/th_46987_Howler_29_2_122_210lo.jpg) (http://img229.imagevenue.com/img.php?loc=loc210&image=46987_Howler_29_2_122_210lo.jpg) (http://img156.imagevenue.com/loc106/th_47020_Howler_30_2_122_106lo.jpg) (http://img156.imagevenue.com/img.php?loc=loc106&image=47020_Howler_30_2_122_106lo.jpg)
Modules :
(http://img177.imagevenue.com/loc384/th_47036_Howler_31_2_122_384lo.jpg) (http://img177.imagevenue.com/img.php?loc=loc384&image=47036_Howler_31_2_122_384lo.jpg)
Some modules inserted into the board slots :
(http://img149.imagevenue.com/loc342/th_47063_Howler_32_2_122_342lo.jpg) (http://img149.imagevenue.com/img.php?loc=loc342&image=47063_Howler_32_2_122_342lo.jpg) (http://img214.imagevenue.com/loc773/th_46962_Howler_33_2_122_773lo.jpg) (http://img214.imagevenue.com/img.php?loc=loc773&image=46962_Howler_33_2_122_773lo.jpg)
I know some of you think I'm moving too slow, but building a guitar amplifier from scratch (especially a solid state one) is very demanding "activity" and takes a lot of time, effort and patience to be properly done. I'm not trying to emulate anything here like ... "turning a transistor into a tube" (maybe this will happen someday ... during the full moon ... just kiddin' ;) ). I would be very happy if the final result turns out to be something that plain sounds good.
>>>¿Slow?<<< No way, you are doing fine. A "big" company with lots of people usually takes around a year to develop a new product, and keeps improving as it's out there, in the frightening real world, where all unexpected bugs appear.
Congratulations on a very fine job.
Juan Manuel Fahey.
A little info on progress ...
Still working on the clean channel. I don't want it to sound "clinically clean", as the vast majority of solid state amps do, so it has to be tweaked very carefully. The sound tweaking is performed using my genuine 1965 Les Paul Pro Deluxe.
(http://img198.imagevenue.com/loc1076/th_96319_LesPaul_122_1076lo.jpg) (http://img198.imagevenue.com/img.php?image=96319_LesPaul_122_1076lo.jpg)
So far, everything slowly fits in its place. Sound is very opened and dynamic. The amp is starting to lose its clean tone when volume pot past 2 o'clock and cleans up well with the guitar's volume control (when cranked). But, there is a little "thing" that still bugs me and I am not completely satisfied with the result. On the verge of distortion, when light picking produces a clean tone and heavy picking produces a distorted tone, everything sounds cool (two and three strings riffs, full chords, single notes) except tones generated by extremely heavy picking high E and B strings in the high neck position. This is evident only when using a plectrum. Playing with fingers doesn't "show this phenomenon". It is not so evident and has nothing to do with sudden "transistor amp distortion", ghost notes, etc ... It just has no place in sound pattern by my criteria, period. I can easily get rid of it, but "standard ways" make sound less open and airy. So I had to modify some of the existing modules and build some new ones to solve the problem.
(http://img154.imagevenue.com/loc484/th_96299_Howler_34_2_122_484lo.jpg) (http://img154.imagevenue.com/img.php?image=96299_Howler_34_2_122_484lo.jpg)
And "the battle" continues ...
I wish you all Merry Christmas (to those celebrating) and Happy New Year. <3) <3) <3)
Good work so far, also, LOVE the guitar!
Impressive piece of Engineering.
I guess you must have full access to a well equipped factory or metalshop, that amp was not built in a log cabin in the woods.
I loved the "motherboard".
I always suggest everybody to get a piece of plywood or pine, mount there a Proto (or two) and screw solidly a piece of aluminum full of holes for jacks, pots and switches, but yours deserves a Nobel Prize.
Congratulations.
Hello Mangas,
First let me say very tidy work, quite stunning in fact.
Your efforts are certainly neater than mine :-[
Something does not sit right in my head with the first post pic, the bottom pic.
The mains input board has the mains cable *Earth wire* terminated on a PCB. Then I assume a thin copper track back to another terminal and then finally a lead to the chassis bolt.
I'm just wondering if this is safe practice?
From memory this would not pass Austrailian standards but other countries will have differing rules.
I personally would make a *Direct unbroken wire* to Chassis terminal from a mains cord.
In fact when I can I make sure the Earth wire is the longest so that in a worst case situation where the cord is yanked from the chassis the Earth wire is the *Last one to break* thereby minimising the risk of shock to the user.
It's a one in a million chance but that's just me.
Having said all that I probably still do things that more experienced folk would see as risky.
But hey that's what is good about other eyes looking at our work, there is often someone who has thought of something I may miss.
Cheers, Phil.
QuoteImpressive piece of Engineering.
I loved the "motherboard".
I always suggest everybody to get a piece of plywood or pine, mount there a Proto (or two) and screw solidly a piece of aluminum full of holes for jacks, pots and switches, but yours deserves a Nobel Prize.
Congratulations.
Thank you J M, for your too kind words. You're making me blush. ::)
QuoteI guess you must have full access to a well equipped factory or metalshop, that amp was not built in a log cabin in the woods.
I wish that was true. Believe it or not, 70% of the amp was assembled on the floor of my study because the desk is not big enough for all of the instruments, modules, wires and cables. That creative disorder of mine is driving my wife crazy. :grr
I have a few pals - one is good with metal, another is good with wood ... All in all, they are a bunch of crazy enthusiasts (like myself) ready to "meet my demands" at reasonable fee. What can I say... I am fortunate to know a couple of guys like that.
QuoteBut hey that's what is good about other eyes looking at our work, there is often someone who has thought of something I may miss.
I couldn't agree more.
QuoteSomething does not sit right in my head with the first post pic, the bottom pic. The mains input board has the mains cable *Earth wire* terminated on a PCB. Then I assume a thin copper track back to another terminal and then finally a lead to the chassis bolt. I'm just wondering if this is safe practice? From memory this would not pass Austrailian standards but other countries will have differing rules. I personally would make a *Direct unbroken wire* to Chassis terminal from a mains cord. In fact when I can I make sure the Earth wire is the longest so that in a worst case situation where the cord is yanked from the chassis the Earth wire is the *Last one to break* thereby minimising the risk of shock to the user.
And I am very glad that the fellow forumers pay that much attention to my posts.
First off all I would like to say that what you see here is not a final product, but the prototype. Only the PCBs have their final form. I'm surprised nobody has mentioned somewhat bizzare chassis construction. Initially my intention was to build something like 1970's Fender Champ - a little practice amp with Volume, Bass and Treble controls. So I bought 8" Jensen speaker, built appropriate cab and ... found out that I have Accutronics type 8 reverb tank spare. And it begun ...
Reverb? ... Why not?
Footswitchable? ... Why not?
Normal / Boost ... Why not?
Footswitchable? ..........
And there I was ... A zillion ideas running through my head, a little neat cabinet with sweet sounding speaker and ... a lack of space in the cabinet. Finally, I managed to tuck all in at the cost of chassis specific shape and component disposition.
The final product will have bigger cabinet, 10" (probably 12") speaker, chassis mounted male IEC main's socket and detachable AC power cord. Main's wiring cable (two layers of PVC insulation) will be mechanically fastened at both ends (Main's PCB (the pic previously posted) and Main's socket) inside the chassis. So, there is no way to "yank the cord" from the main's PCB and break "The Earth wire". Beside the fuse, there are the earth isolation circuit (10 Ohm resistor, 100nF capacitor, two antiparallel diodes) and metal oxide varistor as additional safety components. All capacitors are class X2.
Pretty safe ... I'd say.
Thanks for the details and pic Mangas, :tu:
You have obviously got it all sorted and should be a darn fine piece of well made equipment when it's finally done.
But it is all rather addictive and your wife probably wants to know if you will ever be finished,, LOL.
Phil.
I must say.
This is probably the most impressive looking home built SS amp I have seen.
I am in awe <3)
In fact it looks better and more "pro" than alot of the no-name brand SS I have seen for sale in stores and online.
Also...
Kudos for sharing,and not asking for help then declaring it "proprietary" knowledge.
Like so many seem to do in the DIY arena.
Finally, the time for uploading some preliminary sound samples has come xP xP xP . The clean channel is almost finished. Only a little "polishing" is needed considering a choice of active components and capacitor types (ceramic (np0, silver mica), polyester, polypropylene). Thanks for your patience. All comments are welcome.
A little info on clips :
Fender_1.zip (Fender_Clean.mp3) - Fender Stratocaster, neck and middle position pickups, clean sound (volume on 5, treble on 8, bass on 6, reverb on 5, middle boost off). Had to cut off intro to fit the file into 512kB. Sorry.
Fender_2.zip (Fender_Attenuated.mp3) - Fender Stratocaster, neck position pickup, amp fully cranked, guitar volume pot rolled back (volume on 10, treble on 6, bass on 6, reverb on 3, middle boost on).
Gibson_1.zip (Gibson_Clean.mp3) - Gibson Les Paul Pro Deluxe, both pickups, clean sound (volume on 4, treble on 6, bass on 6, reverb on 5, middle boost off).
Gibson_2.zip (Gibson_On the verge.mp3) - Gibson Les Paul Pro Deluxe, neck pickup, on the verge of distortion (volume on 7, treble on 7, bass on 6, reverb on 5, middle boost on).
Next stop ... The boost channel
The rest of the files ...