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'Please show examples of 4-stage high gain layout'
Author:Joe V (guest: search)
Date: Wed, Jan 03rd, 2007 @ 13:43 ( . )

Hello all,

Could any of you please post links to your chassis shots of working, NON SQUEALING, high gain amps of 4 12ax7 stages or more? I'm trying to learn how to do this. If I don't, I may jump off a bridge in frustration.

Joe V.
www.amplates.com
Custom Faceplates for DIY Guitar Amps

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'Please show examples of 4-stage high gain layout'
Author:Jeff Miller (guest: search)
Date: Wed, Jan 03rd, 2007 @ 14:06 ( . )

My Weber Heather doesn't squeal, but it hums a lot right now - still working on that part ;)

The Heather is a SLO Inspired design...

:)

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'Please show examples of 4-stage high gain layout'
Author:frickecello (registered user: 47 posts )
Date: Wed, Jan 03rd, 2007 @ 14:24 ( . )

You can try adding a signal conditioning filter at the input of your amp (most amps dont have one! to filter 60Hz hum and high freq hiss induced on your cables or guitar, it is quite simple)... Check out the Peavey 5150 EVH schematic, it has numerous 12ax7 gain stages, I am working in a multiple gain stage preamp project but using 3 ecc82/12au7's (medium mu) triodes... and a pair of 12ax7/ecc83's...

Remember the basics to reduce hum:

*LM7806 Regulated DC heater supply.
*Shielded power transformer or at least far from the amp circuit, you can measure its EMF effect area with a compass.
*Use shielded wire in sensistive signal lines.
*Use shielded jacks.

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'Please show examples of 4-stage high gain layout'
Author:frickecello (registered user: 47 posts )
Date: Wed, Jan 03rd, 2007 @ 14:36 ( . )

Measure resistance from chassis ground to mains ground pin, it should be 0.5 ohms maximum, 0.1 ohms is ideal.
Remember the star grounding technique.

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'Please show examples of 4-stage high gain layout'
Author:Tim Benson (registered user: 192 posts )
Date: Wed, Jan 03rd, 2007 @ 14:34 ( . )

Hmmm... If I had my super extreme working correctly I would love to help out.

I'd be willing to bet that Gain Master has built a few amps that would fit that description :)

I am really interested in seeing a good example as well.

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'Please show examples of 4-stage high gain layout'
Author:tkdrew (registered user: 740 posts )
Date: Wed, Jan 03rd, 2007 @ 15:02 ( . )

Here is a link to the gut shots from a four stage DC drive amp I built a little while back. It is freewired and still manages to not squeel. Just be careful with your signal path(if it must cross over its self do it at right angles), and don't be afrid of sheilded wire:-)

pics and schematic

[link]

clips
[link]

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'Please show examples of 4-stage high gain layout'
Author:Billings (guest: search)
Date: Wed, Jan 03rd, 2007 @ 15:02 ( . )

1) Make sure that no more than two preferably out of phase gain stages are running off of any given PS filter section. I'm getting away with three in my amp right now off the first HT filter, but one of them is a resistive mixer so that maybe doesn't count.

2) Have a star ground for the first stage, a second one for the second stage, etc, and star all of those ground points together at a single point. Attenuators, tone controls etc should ground with the following stage.

3) Layout wise, interference between wires that are in phase is going to be what will give you fits. If they're effectively the same signal (e.g. wiper and CW lug off a volume pot) then it doesn't particularly matter.

4) Shield wires between stages. I'm not doing this right now and while I'm not getting squealing i am getting some RF pickup, so I'm guessing this is worth doing. Everywhere I've seen attaches the shield to the ground of the following stage, but I saw a trainwreck schem that attached it to the plate of the following stage. That seems like a great idea to me, dunno if anyone's tried it.

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'Tips for a noise free amp.'
Author:AletheianAlex (registered user: 3532 posts )
Date: Wed, Jan 03rd, 2007 @ 16:58 ( . )

My builds look like rat's nests inside, but are silent as death... like all the old HI-FI gear that was even messier, and even quieter. Radiated fields will kill you... squeels galore. Sheilded wire will help, but it is not a cure all. Everything is excacurbated with higher gains and more stages, so you have to be much more deliberate in your designs.

My tips...

+It starts with a good power supply:
-Get the ripple out! i usually regulate, and then bypass the supply nodes close to the pins with a .1uF CERAMIC capacitor to shunt any noise picked up along the wire run to ground.
-Make sure your rectifier diodes are not radiating RF... use fast, soft recovery diodes and snub them, or use a tube rectifier (i do in almost all mu builds now).
-In addition to regulating, use a CLC first power supply stage... just do it. Capacitors' effectiveness decreases as the impedance increases... that's the ESR problem, but chokes are the opposite, so they compliment each other and work better across the board. They also by their nature, convert sine AC ripple to a more saw tooth shape from their ramping up/down action, so the regulator will more effesctively cancell out the ripple.
-MIND YOUR CURRENT LOOPS! Don't use crappy multi-section can caps. Use seperate capacitors, and place them near the stage that they are filtering and keep the wiring in the loop short. i use 1 cap per triode if they are opposite in phase, if you have two cascading sections that are the same in phase, then seperate their supplies.
-Keep the AC input and recitfying part of the supply HELL AND GONE from the preamp circuit... all the way in the opposite corner of the chassis. Keep the loop around the first filter cap as short as possible so that it does not become a quarter-wave antenna.

+Filaments:
-Elevating AC filaments works really well for getting the ripple noise at a different potential than the cathode, so you are not shooting AC noise into your circuit, but you still have ac travelling around your circuit, which will radiate crap for your sensitive grid nodes to pick up. A better solution is to use a good REGULATED DC supply, with a choke filter and then also elevate it, AND use sheilded twisted pair wiring. This is not neccessary, but it will eliminate completely the chance of filament interference. BUT I must stress that it has to be a GOOD regulated supply, ir else you will be only making things worse.
-Keep your filament wiring short as possible, and use solid wire so that you can make all your bends 90 degree angles... loops are RF antennas! So keep the bands sharp. Keep the filament circuit away from the other wiring. I always send the signal wires in on one side and the filaments on the other. i also use 12v filaments so that I can only have to approach the tube socket from one side, rather than wrapping around to the other side to hook up to pin #9... and as a bonus, you'll need less current. And lay the filaments against the chassis for extra sheilding.
-Even with DC filaments, bypass each tube's filament to ground right on the tube pin with a .1uF CERAMIC capacitor to kill any picked up stray noise in the heater wiring.

+Grids:
-Always always use a grid stopper, and always put it right on the pin. Always make sure that the leads are copper, not copper clad steel, and make sure that the resistor end caps are copper and not zinc... and make sure that the composition of the resistor is not inductive. i use good carbon comp stopper resistors... always....always. If you don't think it is important to use a magnetically inert, non inductive resistor, then just wire up a circuit with a crappy resistor and then put a magnet close to the grid resistor, then do the same with a nice carbon comp... you'll see what i mean. With all the stray fields and cell phone interference around, it becomes very important.
-Make sure that the grid connection is away from ANY other signal carrying wires, or power wires, and especially AC carrying power wires. Make your layout so that NOTHING has to come anywhere near these. I keep the grid wires running to the socket at a radial angle that is perpendicular to the tangent of the heater wires on the opposite side to completely eliminate the possibility of coupling.
-if you do have to cross the grid wires for any reason, keep as much space as possible between the wires and only cross them at right angles

+Transformer layout:
-Orient your transformers in a 3-dimensional plane. Look at the radiating field from a standard E-I core tranny, and orient your three trannies on 3 axies...X, Y and Z, then there can be no coupling. you can keep some distance between them, but if they are oriented properly, I have snugged them up pretty close with no coupling. More important than keeping them away from each other is keeping them away from the preamp and phase inverter! Put them away in that corner where your rectifier circuit is, and then space them out according to the rooom you have available.

+Grounding:
-i run a buss/star ground that keeps the plate supply nodes, grid nodes and cathode nodes in loops around each circuit. it is a star ground that is kinda stretched out. Then reference the preamp buss to ground at the input jack.

The rest of the circuit should practically lay itself out at this point.

+Other considerations:
-Don't use more gain than you need. Why generate uber gain from a section, and then dump it away with a voltage divider? Re-work your operating points so that you get the clipping that you want without having to crank up the gain so much.
-Keep the grid resistance low. Big resistors on the grid will only increase noise and raise the impedance of that node, making it more suceptable to RF and hum. you can bleed off treble in ways other than miller capacitance rolloff with HUGE series resistance. just do the math to get those huge resistors out of the signal path. I usually add just enough series resistance to get the highs to roll off from Miller effect just outside the audio band, and then use plate capacitors or grid capacitors to tailor the high end.

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'Tips for a noise free amp.'
Author:Ken Moon (registered user: 2060 posts )
Date: Wed, Jan 03rd, 2007 @ 17:12 ( . )

Man, that is one awesome post!

I am intrigued about your use of chokes and tube rectifiers. I am building a 2 x 6V6 push-pull amp and have been having trouble deciding on:
- fixed-vs-cathode bias
- tube-vs-ss rectifier
- NFB or no NFB
- CLC vs CRC ps filter

Based on your input, I'm inclined to try the choke and the tube rectifier. I'd like to try cathode bias w/ no NFB for simplicity first, but may need to change if the amp is too squishy.

One question - how is the proper tube rectifier chosen - I have seen both GZ34 and 5U4GB rectifiers on 22w 2x6V6 amps.

Thanks again for your great post Alex :-)

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'Tips for a noise free amp.'
Author:AletheianAlex (registered user: 3532 posts )
Date: Wed, Jan 03rd, 2007 @ 17:38 ( . )

On 01/03/2007 @ 17:12, Ken Moon wrote :
:
: One question - how is the proper tube rectifier chosen - I have seen both GZ34 and 5U4GB rectifiers on 22w 2x6V6 amps.
--



The considerations are based on what you need:
Max B+ current
Max B+ voltage
Available heater current for rectifier
Available heater voltage (eg, 5v or 6v)
Do you need controlled warmup?
How big a first supply cap do you need (this is contingent on the topology of the PSU)?
How much voltage drop across the rectifier's internal resistance can you afford?

My $0.02?

One deciding factor for me is controlled warmup. i like just flipping on one switch and letting the amp warm itself up without a standby switch... i dunno, it just seems a more 'tubey' way to do it. This also gradually brings up the B+ supply rather than just hitting the plates of your tubes with hundreds of volts when you flip it off standby.

For most purposes, a GZ34/5AR4 works for me. It is not as big as a 5U4, and you get that bonus of controlled warmup. It is also indirectly heated... BUT... the cathode is tied to one side of the heater anyway. It also does not drop much voltage... only about 17v at max current. It can put out a decent voltage at decent currents too... about 250mA if you keep it under 500v. It can also take a pretty big input cap--about 60uF.


in comparison, the 5U4 does not have controlled warmup, can only handle an input cap of half the size, draws over 30% more heater current, and drops 3 times the voltage across it's internal resistance, so i don't see the advantage. If you LIKE the voltage drop for sag, just increase the series current limiting resistors on each of the diode plates to get the sag you want. ALSO, GZ34 are cheaper AND JJ/Tesla makes one... if you go 5U4 youare limited to soviet or NOS.

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'FAQ Me, please'
Author:Evan (guest: search)
Date: Wed, Jan 03rd, 2007 @ 17:37 ( . )

Alex's post, that is.

Thanks Alex.

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'FAQ Me, please'
Author:Zoe N Iain (registered user: 8138 posts )
Date: Wed, Jan 03rd, 2007 @ 18:33 ( . )

(Zoe AND Iain) agreed!!!!!!!!!!!

Please FAQ Alex's post, it covers every factor of getting a high gain amp quiet.


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'+1 for the regulated PS'
Author:tkdrew (registered user: 740 posts )
Date: Wed, Jan 03rd, 2007 @ 17:58 ( . )

I used Alex's CLC regulated power supply schem in the amp I posted pics to above and it is spooky quiet.

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' how did you learn all this??'
Author:sdp1234 (guest: search)
Date: Thu, Jan 04th, 2007 @ 11:40 ( . )

I know many of the folks here are engineers and I love thier input although it takes months to understand some of the concepts. Did you learn this by experiance or do you have a background in math, electronics or engineering?

If you learn by experiance, how much time do you spend messing with amps and equiptment.

I've been trying to learn this stuff for three years. Just when I think I'm starting to get a handle on it there is a post like yours and I think "geez.. I don't know anything"

Thanks for the information it will be very helpful in the future!
At the same time, thanks for making me feel very slow and stupid :)

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' how did you learn all this??'
Author:Joe V (guest: search)
Date: Thu, Jan 04th, 2007 @ 11:55 ( . )

On 01/04/2007 @ 11:40, sdp1234 wrote :
I know many of the folks here are engineers and I love thier input although it takes months to understand some of the concepts. Did you learn this by experiance or do you have a background in math, electronics or engineering?
:
: If you learn by experiance, how much time do you spend messing with amps and equiptment.
:
: I've been trying to learn this stuff for three years. Just when I think I'm starting to get a handle on it there is a post like yours and I think "geez.. I don't know anything"
:
: Thanks for the information it will be very helpful in the future!
: At the same time, thanks for making me feel very slow and stupid :)
--



+1

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' how did you learn all this??'
Author:frickecello (registered user: 47 posts )
Date: Thu, Jan 04th, 2007 @ 12:46 ( . )

On 01/04/2007 @ 11:40, sdp1234 wrote :
I know many of the folks here are engineers and I love thier input although it takes months to understand some of the concepts. Did you learn this by experiance or do you have a background in math, electronics or engineering?
:
: If you learn by experiance, how much time do you spend messing with amps and equiptment.
:
: I've been trying to learn this stuff for three years. Just when I think I'm starting to get a handle on it there is a post like yours and I think "geez.. I don't know anything"
:
: Thanks for the information it will be very helpful in the future!
: At the same time, thanks for making me feel very slow and stupid :)
--



Im a robotics engineering student, so I didnt had much valve audio circuit background... I think the first of all is understanding HOW electric circuits work, what are the do's and dont's, and to be able to analyze information (internet sources) to see if it is correct, I have found many mistakes and old school electronic applications in lots of "correct" circuits...

These books are great! :

* Electric Circuits - Nilsson. (truly a classic) (basic calculus required: LaPlace transform, Fourier transform is the most advanced skills needed for this book)
* Valve amplifiers - Morgan Jones. (to the hobbyist)
* High Power Audio Amplifier Construction Manual -Randy Slone. (covers solid state amps and signal conditioning filters, has a very good valve vs SS mythbuster section, hobbyist and technical range no engineer's math required)
* The Ultimate Tone Modifying and Custom Building Tube Guitar Amps Vols. I & II - Kevin O'Connor (I think the most comprehensive valve books available, HIGHLY RECOMMENDED)

I think that is all you need, of course there are lots of great books, but you will have a solid reference with those books on your bench. Little calculus is needed (basic stuff like differentiation and integration).

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' how did you learn all this??'
Author:frickecello (registered user: 47 posts )
Date: Thu, Jan 04th, 2007 @ 12:47 ( . )

The Ultimate Tone Volume 4 -
Advanced Techniques for Modern Guitar Amp Design, by Kevin O'Connor

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'I think everyone shoudl post their info'
Author:AletheianAlex (registered user: 3532 posts )
Date: Thu, Jan 04th, 2007 @ 13:49 ( . )

On 01/04/2007 @ 12:46, frickecello wrote :
On 01/04/2007 @ 11:40, sdp1234 wrote :
: I know many of the folks here are engineers and I love thier input although it takes months to understand some of the concepts. Did you learn this by experiance or do you have a background in math, electronics or engineering?
: :
: : If you learn by experiance, how much time do you spend messing with amps and equiptment.
: :
: : I've been trying to learn this stuff for three years. Just when I think I'm starting to get a handle on it there is a post like yours and I think "geez.. I don't know anything"
: :
: : Thanks for the information it will be very helpful in the future!
: : At the same time, thanks for making me feel very slow and stupid :)
: --
:
:

:
: Im a robotics engineering student, so I didnt had much valve audio circuit background... I think the first of all is understanding HOW electric circuits work, what are the do's and dont's, and to be able to analyze information (internet sources) to see if it is correct, I have found many mistakes and old school electronic applications in lots of "correct" circuits...
:
: These books are great! :
:
: * Electric Circuits - Nilsson. (truly a classic) (basic calculus required: LaPlace transform, Fourier transform is the most advanced skills needed for this book)
: * Valve amplifiers - Morgan Jones. (to the hobbyist)
: * High Power Audio Amplifier Construction Manual -Randy Slone. (covers solid state amps and signal conditioning filters, has a very good valve vs SS mythbuster section, hobbyist and technical range no engineer's math required)
: * The Ultimate Tone Modifying and Custom Building Tube Guitar Amps Vols. I & II - Kevin O'Connor (I think the most comprehensive valve books available, HIGHLY RECOMMENDED)
:
: I think that is all you need, of course there are lots of great books, but you will have a solid reference with those books on your bench. Little calculus is needed (basic stuff like differentiation and integration).
--



Honestly, one of the things that i wish this board had is a user profile where everyone could post their backgrounds. I think that knowing how people came to the knowledge that they have is very helpful in directing everyone's studies.

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'I think everyone shoudl post their info'
Author:Marc Frickecello (guest: search)
Date: Thu, Jan 04th, 2007 @ 14:41 ( . )

Yes, it is a very good idea.

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'I think everyone shoudl post their info'
Author:Dan N (guest: search)
Date: Thu, Jan 04th, 2007 @ 14:52 ( . )

On 01/04/2007 @ 13:49, AletheianAlex wrote :
'I think everyone should post their info'
: Honestly, one of the things that i wish this board had is a user profile where everyone could post their backgrounds. I think that knowing how people came to the knowledge that they have is very helpful in directing everyone's studies.


Here is one such thread [link]

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'I think everyone shoudl post their info'
Author:Dan N (guest: search)
Date: Fri, Jan 05th, 2007 @ 11:19 ( . )

And here is another
[link]
and another
[link]

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'I think everyone shoudl post their info'
Author:tkdrew (registered user: 740 posts )
Date: Thu, Jan 04th, 2007 @ 15:11 ( . )

I agree a little background on people tends to help out sometimes.

As for me I have a piddly little AS degree in electronics and an AS degree in Instrumentation(industrial type control systems). I have worked in industrial electronics for the last 15 years, started out working for Texas Instruments Doing component level troubleshooting on various projects they were custom manufacturing for customers(Cisco, IBM, ATT, etc). I currently work for American Greetings troubleshooting PLC systems and motor drives. I only started into this tube stuff a year or so ago and have spent a lot of time reading and prototyping some circuits. Not that I have a lot of expertise to share, still trying to learn most of it myself.

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'I think everyone shoudl post their info'
Author:sdp1234 (guest: search)
Date: Thu, Jan 04th, 2007 @ 16:33 ( . )

Thanks Alex. Looks like you put a lot of time into this. I'll keep plugging away and hopfully my builds will get better. My wife will see to it that I don't spend too much time with this hobby. Afterall it doesn't pay any bills and it isn't quality time with her or the kids. But it is a lot of fun and has become my favorite hobby.

I think this site may help

[link]


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'I think everyone shoudl post their info'
Author:AletheianAlex (registered user: 3532 posts )
Date: Thu, Jan 04th, 2007 @ 16:53 ( . )

On 01/04/2007 @ 16:33, sdp1234 wrote :
:
: I think this site may help
:
: [link]
:
:
--




hey! Look at that! Cool

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'I think everyone shoudl post their info'
Author:Miles O'Neal (registered user: 13998 posts )
Date: Fri, Jan 05th, 2007 @ 10:20 ( . )

So how come Alex's info isn't posted? Hmmmm?

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'I think everyone shoudl post their info'
Author:Merlin (registered user: 5235 posts )
Date: Fri, Jan 05th, 2007 @ 10:23 ( . )

On 01/05/2007 @ 10:20, Harrison Ford Prefect wrote :
So how come Alex's info isn't posted? Hmmmm?
--


And what happened to mine?!

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'Info posted...'
Author:AletheianAlex (registered user: 3532 posts )
Date: Fri, Jan 05th, 2007 @ 15:03 ( . )

On 01/05/2007 @ 10:20, Harrison Ford Prefect wrote :
So how come Alex's info isn't posted? Hmmmm?
--



Done...

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'Info posted...'
Author:Stephen Keller (registered user: 6256 posts )
Date: Fri, Jan 05th, 2007 @ 17:44 ( . )

Henry,

You probably already know about John Fisher's site, but he has some very good info on coil winding.

[link]

Stph

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'Info posted...'
Author:Stephen Keller (registered user: 6256 posts )
Date: Fri, Jan 05th, 2007 @ 18:29 ( . )

Dang, how did this get here. I was replying to Henry Ramsey over in a completely different thread.

Stph

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'I think everyone shoudl post their info'
Author:Miles O'Neal (registered user: 13998 posts )
Date: Fri, Jan 05th, 2007 @ 00:42 ( . )

I've asked Chris for a link to this, but he never got around to it...

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' how did you learn all this??'
Author:AletheianAlex (registered user: 3532 posts )
Date: Thu, Jan 04th, 2007 @ 13:46 ( . )

On 01/04/2007 @ 11:40, sdp1234 wrote :
I know many of the folks here are engineers and I love thier input although it takes months to understand some of the concepts. Did you learn this by experiance or do you have a background in math, electronics or engineering?
:
: If you learn by experiance, how much time do you spend messing with amps and equiptment. --



Are you asking me? If so... then I just tinker and read a lot. What I know is just a drop in the bucket, and i wish that i had more time to read up and study, but there are only so many hours in the day. There are definatley guys on this board that are better vearsed in this stuff... i just want to help people--i figure that if i can alieviate some frustration and save some study time for some folks, they will stick with this and build some great amps. Not being egotistical... here is a rundown of how I learned this crap in case it helps anyone out there.

I have no formal electronics education, except a few freshman level E.E. courses and I am not the best mathematician either, and although i do love math...I got as far as undergrad-level calc and physics before my brain exploded. i dropped the engineering major early on because I really wanted to learn about tube electronics... but they didn't teach that anymore... it was all digital crap! There were really one 2 analog courses at all actually. There are so many guys that know SOOOO much about this stuff, but are doing other things. If i were a rich man, I would pay guys like Paul Reid (PRR on various forums) to come to my apartment and lecture every day. i have learned a lot from guys on this board and others. Paul Ruby and Randall Aiken have been invaluable resources, as well as Zaphod and many others. I also read John Brooksie's TubeCAD journal, and have subscribed to Glass Audio for years. i have also learned a lot from Lynn Olson, Gary Pimm, Norman Crowhurst, Uncle Ned, Andrea Ciuffoli... etc etc etc, as well as other forums like Audio Asylum and prodigy professional.

I had some hands on electronics experience in industrial automation... which will teach you good electricity handling practices. But as far as audio electronics, in middle school, I picked up the Forrest Mims books that they used to sell at radio shack... then some college electronics textbooks, and finally the Radiotron Designer's Handbook. I just kept an eye on thrift stores for smelly old electronics books and asked a lot of questions of grouchy old engineers.

I got ahold of some Marshall schematics in college, and after working with solid state control systems... with their thousands of connections, 12 foot tall enclosures and schematics that were dozens of pages long.... the Marshall just looked like a toy in comparison. I started doing lots of mods and repairs on amps, effects and studio gear--and still do, which teaches you a lot about what works and what does not. Guitar amps are simple circuits, but they are fun because of their unpredictable and non-linear behavior!

But honestly, it came down to buying a meter, a scope, and some parts and just going at it. I have probably built up hundreds of circuits by now, as well as simulating thousands, and I read and re-read the RDHB and other old texts every night before i go to sleep, and in the van on the way to gigs... and i am never without a calculator. Learning the basic math and how to plot loadlines (for tubes and transistors) takes a lot of the mystery out of it, and then it is a matter of building things up and seeing how they work out. i have dozens of notebooks full of my little 'lab notes,' which eases the burden of remembering all this crap. I just have an attitude that i would rather work and research to solve my problems then ask someone to fix them for me. I have learned more by blowing things up and building dozens of buzzy humming amps then i have from building sucessful ones.

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'Please show examples of 4-stage high gain layout'
Author:Jed E. (registered user: 195 posts )
Date: Wed, Jan 03rd, 2007 @ 18:23 ( . )

Here are some pics of a 4 stage-high gain amp I built awhile back:
[link]
[link]
[link]
[link]

Hope that helps,

Jed

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'Please show examples of 4-stage high gain layout'
Author:Joe V (guest: search)
Date: Wed, Jan 03rd, 2007 @ 20:14 ( . )

Jed, that's inspirational. Thanks for posting that. Those photos will help a lot. How does that amp sound? I take it it's 2 channels? Do you have a schematic we could look at for reference?

Alex, your post depressed the hell out of me. Every time I think I know my ear from my elbow re: ampbuilding I find out nope, there's a reason that I can't hear anything through my shirtsleeves. :-/

Seriously, Alex, thanks for the excellent response. I think you've forgotten more about this stuff than I'll ever learn....

For instance, what's a CLC power supply? Is that shorthand for Cap/Choke/Cap?

Also, how do I go about regulating B+? Do you have a reference schematic that we all could look at? Not one of your proprietary designs, but something more generic to work from?

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'Please show examples of 4-stage high gain layout'
Author:tkdrew (registered user: 740 posts )
Date: Wed, Jan 03rd, 2007 @ 20:32 ( . )

I hope Alex doesn't mind me posting this link, this is his circuit that I followed to make the regulated PS for my amp. I found the link in an old post he had made on MOSFET regulators. It works VERY well, hard to believe how quite the amp is, even with everything dimed you have to really listen to hear if the amp is on.

[link]

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'Please show examples of 4-stage high gain layout'
Author:AletheianAlex (registered user: 3532 posts )
Date: Wed, Jan 03rd, 2007 @ 21:35 ( . )

On 01/03/2007 @ 20:32, tkdrew wrote :
I hope Alex doesn't mind me posting this link, this is his circuit that I followed to make the regulated PS for my amp. I found the link in an old post he had made on MOSFET regulators. It works VERY well, hard to believe how quite the amp is, even with everything dimed you have to really listen to hear if the amp is on.
:
: [link]
--



Heh... no I don't mind... that is an old one.

Anyway, if you bypass the mosfet with a diode, or if the mosfet already has a diode in it, then you can make the caps larger... as big as you need. i like to use another few regulators too if the B+ for the output tube plates is a lot higher than the B+ for the screens and/or preamp... one for the screen and one for the preamp as opposed to dropping resistors, but if the voltages are all similar, it's no biggie.

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'Please show examples of 4-stage high gain layout'
Author:AletheianAlex (registered user: 3532 posts )
Date: Wed, Jan 03rd, 2007 @ 21:52 ( . )

On 01/03/2007 @ 20:14, Joe V wrote : For instance, what's a CLC power supply? Is that shorthand for Cap/Choke/Cap?
:
: Also, how do I go about regulating B+? Do you have a reference schematic that we all could look at? Not one of your proprietary designs, but something more generic to work from?
--




Yeah, CLC meanc cap-choke-cap. it is also called a "pi" filter .


As far as a reference schem... use the one that THDrew posted below. it's just a mosfet and a voltage divider... pretty simple. Remember to heat sink the mosfet and remember that the mosfet tab (and heatsink if you don't use an isolating spacer) will have high voltage on it.... so NO TOUCHEY THE MOSFET! You can do it with tubes instead, but it is a huge pain in the butt.

The capacitor values are whatever you need. With a regulated supply, you don't need piles of capacitance, but you should have a decent amount right after the rectifier... if it is a tube rectifier, then jujst use whatever the data sheet recommends. There is a bit of math that you can do to determiune the minimum value there, but i won't bother with it right now.

Then the regulator, followed by another cap that will be your latgest since it feeds the plates of the output tubes, and you need enough capacitance to act as a resevoir for the plate current.

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'Please show examples of 4-stage high gain layout'
Author:Joe V (guest: search)
Date: Wed, Jan 03rd, 2007 @ 22:53 ( . )

On 01/03/2007 @ 21:52, AletheianAlex wrote :
On 01/03/2007 @ 20:14, Joe V wrote : For instance, what's a CLC power supply? Is that shorthand for Cap/Choke/Cap?
: :
: : Also, how do I go about regulating B+? Do you have a reference schematic that we all could look at? Not one of your proprietary designs, but something more generic to work from?
: --
:
:

:
:
: Yeah, CLC meanc cap-choke-cap. it is also called a "pi" filter .
:
:
: As far as a reference schem... use the one that THDrew posted below. it's just a mosfet and a voltage divider... pretty simple. Remember to heat sink the mosfet and remember that the mosfet tab (and heatsink if you don't use an isolating spacer) will have high voltage on it.... so NO TOUCHEY THE MOSFET! You can do it with tubes instead, but it is a huge pain in the butt.
:
: The capacitor values are whatever you need. With a regulated supply, you don't need piles of capacitance, but you should have a decent amount right after the rectifier... if it is a tube rectifier, then jujst use whatever the data sheet recommends. There is a bit of math that you can do to determiune the minimum value there, but i won't bother with it right now.
:
: Then the regulator, followed by another cap that will be your latgest since it feeds the plates of the output tubes, and you need enough capacitance to act as a resevoir for the plate current.
--



Thanks again, man. Great info.

Joe V
www.amplates.com
Custom Faceplates for DIY Guitar Amps

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'Please show examples of 4-stage high gain layout'
Author:Joe V (guest: search)
Date: Wed, Jan 03rd, 2007 @ 23:30 ( . )

I have a stupid question already. Please pardon my ignorance here, but if you use the formula for setting B+ in the schematic, B+ = R2/(R1+R2), you will always get a negative number. Please spell it out for me someone, I'm an editor, not a math whiz. :0(


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'Please show examples of 4-stage high gain layout'
Author:Joe V (guest: search)
Date: Wed, Jan 03rd, 2007 @ 23:32 ( . )

On 01/03/2007 @ 23:30, Joe V wrote :
I have a stupid question already. Please pardon my ignorance here, but if you use the formula for setting B+ in the schematic, B+ = R2/(R1+R2), you will always get a negative number. Please spell it out for me someone, I'm an editor, not a math whiz. :0(
:
:
--



Rather, not a negative number, but I meant to say less than one.

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'Please show examples of 4-stage high gain layout'
Author:AletheianAlex (registered user: 3532 posts )
Date: Thu, Jan 04th, 2007 @ 00:23 ( . )

On 01/03/2007 @ 23:30, Joe V wrote :
I have a stupid question already. Please pardon my ignorance here, but if you use the formula for setting B+ in the schematic, B+ = R2/(R1+R2), you will always get a negative number. Please spell it out for me someone, I'm an editor, not a math whiz. :0(
:
:
--



That's OK... I'm just a musician.

Anyway, I should have been more careful about the syntax of that little equasion. That is the math for a voltage divier, so:

R2/(R1+R2)=X
X*input voltage=regulated voltage


Example, R1=220k, R2=470k, input voltage=400v

So you have:
470*(220+470)=0.68

0.68*400v = 272v regulated B+ output

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'Please show examples of 4-stage high gain layout'
Author:Joe V (guest: search)
Date: Thu, Jan 04th, 2007 @ 10:31 ( . )

On 01/04/2007 @ 00:23, AletheianAlex wrote :

:
: That's OK... I'm just a musician.
:
: Anyway, I should have been more careful about the syntax of that little equasion. That is the math for a voltage divier, so:
:
: R2/(R1+R2)=X
: X*input voltage=regulated voltage
:
:
: Example, R1=220k, R2=470k, input voltage=400v
:
: So you have:
: 470*(220+470)=0.68
:
: 0.68*400v = 272v regulated B+ output
--



Ah yes! That makes much more sense. Thanks again, Alex.

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'Please show examples of 4-stage high gain layout'
Author:AletheianAlex (registered user: 3532 posts )
Date: Thu, Jan 04th, 2007 @ 00:28 ( . )

On 01/03/2007 @ 23:30, Joe V wrote :...I'm an editor, not a math whiz. :0(
:
:
--



What is it that you edit anyway?

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'Please show examples of 4-stage high gain layout'
Author:Joe V (guest: search)
Date: Thu, Jan 04th, 2007 @ 10:26 ( . )

On 01/04/2007 @ 00:28, AletheianAlex wrote :
On 01/03/2007 @ 23:30, Joe V wrote :...I'm an editor, not a math whiz. :0(
: :
: :
: --
:
:

:
: What is it that you edit anyway?
--



Right now, actuarial standards, believe it or not. In the past, I've done much more fun things, like 2 different computer gaming magazines, tech mags, medical mags....

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'PIC'
Author:Brian S. (registered user: 1751 posts )
Date: Thu, Jan 04th, 2007 @ 14:30 ( . )

Check the Super schematic on the p1-eX page. I included a picture of a build using terminal strips.

Brian

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'Please show examples of 4-stage high gain layout'
Author:Jed E. (registered user: 195 posts )
Date: Thu, Jan 04th, 2007 @ 10:46 ( . )

Yep its 2 channels. I don't have a schem with me but the clean is basically a P1 and the dirty is similar to gainmaster's super extreme except with different cathode values and voltage divider values. The tube layout is as follows:
V1a = 1st stage clean
V1b = 1st stage dirty
V2a = 2nd stage clean
V2b = 2nd stage dirty
V3a = 3rd stage dirty
V3b = 4th stage dirty
V4 = fx loop
V5 = PI
V6-V7 = those wonderful KT66 power tubes

Hope this helps a bit.

Jed

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