# Amp and Preamp emulators



## Barry (Oct 28, 2019)

Intrigued by these, where do put them in your signal chain? Into the effects return? straight to the mixer? I would assume after some or most of your other pedals


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## Nostradoomus (Oct 28, 2019)

If you go guitar —-> preamp pedal —-> FX Return on your amp you will effectively bypass the preamp section of your amp.


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## Nostradoomus (Oct 28, 2019)

Oh and start with your volume very low on the pedal...on some amps (depending on fx return setup, some have the master volume before or after the loop) this results in your pedals volume control being your master volume as well


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## Barry (Oct 28, 2019)

Nostradoomus said:


> If you go guitar —-> preamp pedal —-> FX Return on your amp you will effectively bypass the preamp section of your amp.


I would think that would be the most obvious, I have a GuitarPCB King of the Brits I run straight into my Twin Reverb RI, gives me the best of both worlds


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## Nostradoomus (Oct 28, 2019)

Yeah, it gets interesting on my Laney vh100r...it has a sidechain insert loop, cool stuff!


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## Chuck D. Bones (Oct 29, 2019)

I run 2 amps at home, in stereo.  Nothing in the effects loops.  Last 3 pedals in the chain are: Amp-in-a-Box -> Nobels CH-D chorus, stereo output -> Behringer EM600 stereo echo and then that feeds the two amps.  That CH-D is a little noisy, so I'm hoping for an FV-1 solution out of PedalPCB.  Amps are Monoprice 15W (copy of Laney C15) and Monoprice 5W (copy of Laney Cub 8).  For the Amp-in-a-Box, I've been going back & forth between the Covert & Brown Betty.


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## Nostradoomus (Oct 29, 2019)

Once I ran a stereo rig I never looked back. Right now it’s the trusty Laney with an Olde Crow 2x15 and a Mesa DC5 combo.


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## Mourguitars (Oct 29, 2019)

Chuck D. Bones said:


> I run 2 amps at home, in stereo.  Nothing in the effects loops.  Last 3 pedals in the chain are: Amp-in-a-Box -> Nobels CH-D chorus, stereo output -> Behringer EM600 stereo echo and then that feeds the two amps.  That CH-D is a little noisy, so I'm hoping for an FV-1 solution out of PedalPCB.  Amps are Monoprice 15W (copy of Laney C15) and Monoprice 5W (copy of Laney Cub 8).  For the Amp-in-a-Box, I've been going back & forth between the Covert & Brown Betty.



Did you Mod those amps Chuck ? I heard they are a great bang for the buck...!


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## Chuck D. Bones (Oct 29, 2019)

I did mod them a little bit.  They are both great amps right outta the box, but the _C3_ tubes are not the greatest.  
I ran the 15W amp for about 100hrs right after I got it, then checked the bias (it was good) and tested all of the tubes.  They all checked good.  A year later, 2 of the 3 12AX7B's tested out out spec.  The original EL84s were ok, but since I was replacing the other tubes, I replaced them also.  I replaced V1 with a JJ 12AT7.  V2 & V3 got replaced with JJ 12AX7As.  V4 & V5 got replaced with a matched set of JJ EL84s.  By that time the warranty had expired, so I replaced all of the high-voltage electrolytic caps _before _they failed. Some of them looked like counterfeit Rubycon caps because the logo was wrong. The only other thing I did to that amp was install a step attenuator between the amp & internal speaker so I could crank it at home without rattling the windows.
The 5W amp played well for maybe 50hrs, then V1 (12AX7B) got very noisy.  Replaced it with a JJ.  20 or so hrs of operation later, the amp is dead.  Blown fuse.  Visual inspection revealed a blown ceramic cap in the HV supply.  The cap was marked 1KV, so I know a line transient didn't kill it.  I replaced all 3 ceramics in the HV supply and the fuse with _good _parts.  While I was in there, I replaced the TONE pot with a C250K.  It was B250K, but most of the action took place between 8 and 10.  The way the TONE pot is wired, it's a treble cut for the bottom 90% of the rotation and a presence control for the top 10% of rotation.  Changing to C taper fixed that, now it's closer to 50/50.  It gets pretty loud thru the internal 8" speaker.   I connected it to an external 15" and it was like it grew an extra set of balls!
I do recommend them, cuz they sound really good and _are _great bang for the buck. Just be prepared for the possibility of repairing them or returning them under warranty. Wait for them to go on sale, if that ever happens again.


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## Mourguitars (Oct 29, 2019)

Lol....I knew you would mod them !.... yea people were buying them for a good pedal platform over at the gear page a few years back...what’s hot and not changes like the wind over there ...always a good read over there as well...lots of good info on pedals. I went the low watt amps for a while...really all you need  at home anyway

I had a Blackstar HT-5 head and it took pedals well , sold it bought a Phaze Daisy cutter ...way to much treble hence the name  , somebody offered me a straight up trade for the HT-20 head ..so I done that but I liked the HT-5 better and had E nuff power , way to much power for home use..I bought one of those load boxes of eBay and it worked well...now I’m back to my Rack after going the AX8 route for a few years...sold it and back to pedals well building them and having more fun than tweaking the Fractal ..uggh....and Rack effects in stereo..

I like JJ tubes as well...I have a friend who will spend $200  or more on a NOS 12ax7 ... but that’s his thing , I can’t hear that much of a difference other than a tube is bright or dark sounding...personally I can change that with a pickup or a speaker change or mix....or a pedal ....

Might need to recap my JMP-1 pre soon ...it’s over 20 yrs old...hopefully when it needs it I’ll have E nuff experience to do it.....been reading schematics and starting to understand things now...no good tech’s around my area I trust..I would like to build a small amp one day..kit form then upgrade it


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## tdukes (Oct 30, 2019)

I am using:
          [all other effects] --> Tweed Sound --> Frog Preamp --> UniCab --> DI Box

No amp. The Frog Preamp was built with a PCB from FrogPedals.com. It was a little more difficult to build because a lot of the circuit is at 185V and I am not used to looking for that voltage capacitor. I am pretty sure the Frog pedal can kill you so don't open it while its plugged in.


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## Chuck D. Bones (Oct 30, 2019)

You'll know when your amp needs to be recapped.  It will tell you.  First, it will start to sound better than it ever did, then it will start to smell worse than it ever did.  Then a fuse blows.


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## Chuck D. Bones (Oct 30, 2019)

tdukes said:


> The Frog Preamp was built with a PCB from FrogPedals.com. It was a little more difficult to build because a lot of the circuit is at 185V and I am not used to looking for that voltage capacitor. I am pretty sure the Frog pedal can kill you so don't open it while its plugged in.



Things to know about tube circuits:
1) The voltages can be lethal.  Even if the shock doesn't kill you, it can ruin your day.  Filter caps can hold their charge for hours in some circuits.  Always assume they are full charged.  A clip lead that is grounded at one end and has a 1K 1W resistor at the other end makes a handy discharge wand.  Then measure all high-voltage caps with a DMM before touching anything with your fingers.
2) Tube circuits run HOT, so it's a good idea to up the voltage rating on capacitors and semiconductors (rectifier diodes mostly) and power ratings on resistors.  They will last much longer.
3) The high voltage rail will be the highest voltage right after the circuit is turned on, before the tubes have warmed up.  Everything needs to be able to withstand that voltage, even though the circuit spends 99% of the time at a lower voltage.

Sometimes you have to work on a tube circuit while it's powered up, like when you're setting the bias on output tubes.  I've been working on tube circuits for many years.  I only got this old by being careful.  It still makes me nervous.


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## Nostradoomus (Oct 31, 2019)

Yup...whenever I bias/do a quick poke around in my amps it’s always with one hand behind my back


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## TomShadow (Nov 6, 2019)

Chuck D. Bones said:


> Things to know about tube circuits:
> 1) The voltages can be lethal.  Even if the shock doesn't kill you, it can ruin your day.  Filter caps can hold their charge for hours in some circuits.  Always assume they are full charged.  A clip lead that is grounded at one end and has a 1K 1W resistor at the other end makes a handy discharge wand.  Then measure all high-voltage caps with a DMM before touching anything with your fingers.
> 2) Tube circuits run HOT, so it's a good idea to up the voltage rating on capacitors and semiconductors (rectifier diodes mostly) and power ratings on resistors.  They will last much longer.
> 3) The high voltage rail will be the highest voltage right after the circuit is turned on, before the tubes have warmed up.  Everything needs to be able to withstand that voltage, even though the circuit spends 99% of the time at a lower voltage.
> ...


I stumbled upon the awesomeness of Pedal building because I fell in love with how a 5f1 champ sounded in a youtube video and since realizing how dangerous building one can be, I thought I should get some experience through building pedals.
For anyone interested in learning/building tube amps, https://robrobinette.com/Tube_Amp_Safety.htm is the goto place. Tons of great information.
Also, Uncle Doug on youtube has a great knack for explaining tube amp concepts in layman terms.

Just bought this lil beauty last week for 80 bucks on craigslist. My first tube amp   Sounds great to my amateur ears. Wanna enjoy it for a while before I do some mods to it. Exciting times


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## zgrav (Nov 6, 2019)

Another thing is that old tube amps can be running at higher voltages than they were built for.  Old tube amps were built for 110v AC.  Running them at 120v AC gets converted into a higher DC voltage on the tubes so the tubes than the original design called for.


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## chongmagic (Nov 6, 2019)

Chuck D. Bones said:


> I run 2 amps at home, in stereo.  Nothing in the effects loops.  Last 3 pedals in the chain are: Amp-in-a-Box -> Nobels CH-D chorus, stereo output -> Behringer EM600 stereo echo and then that feeds the two amps.  That CH-D is a little noisy, so I'm hoping for an FV-1 solution out of PedalPCB.  Amps are Monoprice 15W (copy of Laney C15) and Monoprice 5W (copy of Laney Cub 8).  For the Amp-in-a-Box, I've been going back & forth between the Covert & Brown Betty.



Chuck have you tried the VHS yet with chorus?


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## Chuck D. Bones (Nov 6, 2019)

I don't have a VHS, so no, not yet.  I have another chorus pedal, but like the VHS, it's not stereo out.


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## Chuck D. Bones (Nov 6, 2019)

[QUOTE="Just bought this lil beauty last week for 80 bucks on craigslist. My first tube amp  Sounds great to my amateur ears. Wanna enjoy it for a while before I do some mods to it. Exciting times 
[/QUOTE]

You got a great deal on that!  How does the digital reverb sound?


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## TomShadow (Nov 6, 2019)

Chuck D. Bones said:


> [QUOTE="Just bought this lil beauty last week for 80 bucks on craigslist. My first tube amp  Sounds great to my amateur ears. Wanna enjoy it for a while before I do some mods to it. Exciting times



You got a great deal on that!  How does the digital reverb sound?
[/QUOTE]

Sounds pretty good to me, I leave it at 3 and it adds a nice layer. But then I have nothing to compare it to, People in other forums seem to think it's decent.


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## Chuck D. Bones (Nov 7, 2019)

Me, I'm partial to the spring reverbs, they sound so natural and organic.  It's probably because that's what I'm used to hearing.  There's not much to mod on those little tube amps. You can swap tubes, but if the ones you have are working then it might not make any sonic difference.  Lotta people like to change out speakers, but it's really a matter of taste and you can end up spending more on a speaker than you did on the amp.  That amp has an external speaker jack, so you can test drive speakers before installing them.  Or just play thru an external speaker.  It will sound completely different thru a 12" or 15."


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## zgrav (Nov 7, 2019)

I have a small Elektar tube amp I bought about 18 years ago or so.  At the time it had gotten a lot of interest as a nice amp that folks were modding.  I swapped the speaker on it and made some suggested changes to the parts based on a lot of forum discussions, like removing a negative feedback loop to open up the sound.  I replaced the filter caps on it this summer and restored most of the circuit back to its stock configuration to see if I liked it better, or at least liked it enough to leave it that way.  Chuck's suggestion to plug different speakers into the amp will do more to change the sound than tweaking the circuit, especially if you are going into bigger speakers.


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## TomShadow (Nov 7, 2019)

Even though I have never tried a spring reverb in person, I can tell it does sound more natural from youtube videos, sounds very springy  
The ultimate mod would be to put a spring reverb into it ?

Some of the_ *mods* _suggested are simple and might help me understand the schematic better like adding bright caps across the gain and volume pots and stuff like adding a boost switch or a 3-way negative feedback loop. 
There are so many mods suggested _*here*_, I think it's a simple enough platform to experiment and understand some of these concepts.  
Right now it lacks that deep bass and chime of fender amps (partly it's my guitar) but maybe adding a fender style tone stack might help? who knows buts its fun and exciting ?

I bet a bigger speaker will sound awesome, but I live in a small apartment and neighbours are right next to the bedroom. There is an 8in speaker by Jensen C8r relatively inexpensive at $35, which apparently makes a big difference.

That's a good idea to test it out with some external speakers. Maybe ill just walk into a Guitar center with it


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## zgrav (Nov 7, 2019)

Another mostly-easy thing to do.  If the amp is open back, you could try closing the back and see if you like the sound better.


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## TomShadow (Nov 7, 2019)

zgrav said:


> Another mostly-easy thing to do.  If the amp is open back, you could try closing the back and see if you like the sound better.


That's a good idea, ill try it out.


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## Gordo (Nov 7, 2019)

Interesting perspective on the spring reverb.  Hated it when I was a kid (back when they invented fire) and it's carried over since.  I've fiddled with some stand alone units that were cool but in the end I've always preferred digital.  I use Amplitube as my song learning weapon of choice and the spring emulation makes me nuts.  My first amp was a Traynor Guitar Mate (which I'd kill to have now) and never loved the reverb.  Heresy, I know.


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## Chuck D. Bones (Nov 7, 2019)

There is only so much you can do to improve the bass response.  On those little amps, the frequency response, particularly the low end, is limited by the output transformer.  A bigger speaker definitely helps.  I suggest that you're better off loving that amp for what it is.  If you want more bass, you need an amp with a push-pull power section (2 output tubes) and a 12" speaker.


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## mywmyw (Nov 8, 2019)

Gordo said:


> Interesting perspective on the spring reverb.  Hated it when I was a kid (back when they invented fire) and it's carried over since.  I've fiddled with some stand alone units that were cool but in the end I've always preferred digital.  I use Amplitube as my song learning weapon of choice and the spring emulation makes me nuts.  My first amp was a Traynor Guitar Mate (which I'd kill to have now) and never loved the reverb.  Heresy, I know.


often the lesser brands used cheap pans and the circuits didnt seem to get the best out of them. ive heard a lot of vintage spring reverbs that sounded like butt.


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## TomShadow (Nov 8, 2019)

Chuck D. Bones said:


> There is only so much you can do to improve the bass response.  On those little amps, the frequency response, particularly the low end, is limited by the output transformer.  A bigger speaker definitely helps.  I suggest that you're better off loving that amp for what it is.  If you want more bass, you need an amp with a push-pull power section (2 output tubes) and a 12" speaker.


That's good to know Chuck. I do love it ?


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