Why did I buy another 80's Fender solid state amp ????
One, I can maybe understand.....just to have one to play around with...but two??.....there may be some underlying issues here...
To much disposable income ??
Trying to relive my youth ??
To cheap to just drop the $$ on a decent small tube amp ??
The SS amps are to cheap to pass up ?? (sound like my wife buying shoes....)
I'm just plain dumb ??
I think the real reason may be a combination of all of that....and that the first one I got (an excellent Harvard Reverb II) was so freekin' good that I thought "Man....I better get another one like this ...these things are great! I'll get one like it but a little bigger with a 12" speaker, for just a little more volume"
Getting another amp with a 12" speaker also opens up better opportunities for speaker swaps / upgrades.
I already have a Monoprice with a 12" that I plan on using in conjunction with this new amp.....so if I get any new speakers....I'll have 2 different amps to try it in....this doubles my chances for a home run.
So of course...the one that I decide to get ....a Fender Sidekick Reverb 35, is...... well.......less that stellar right out of the box....
but....
Most of the issues *seem* like they can be solved pretty quickly and pretty easily, with a minimum investment in parts and time.
Don't get me wrong....the amp sounds OK, the clean sound is exactly what you'd expect, pretty much "standard Fender clean" .....but...it's got a couple little issues that bug the crap out of me, and I think fixing these issues will make the amp significantly better (at least better for me anyway).
1. The reverb is ....crappy for a real spring tank. It should be MUCH better.
2. The volume goes from zero to LOUD! in about 2-3 digits on the volume knob. This makes it really kind of difficult to dial in a volume that is "just right". It's either off or it's ON!
3. The gain...well.....it seems pretty lame on this amp....may not be anything I can do about that...but we'll see....
The reverb issue is probably a pretty simple fix.
A new/better tank.
According to Amplified Parts ....https://www.amplifiedparts.com/products/reverb-tank-mod-8eb2c1b this MOD tank should be a replacement... or....https://www.tubesandmore.com/products/reverb-tank-accutronics-8eb2c1b this Accutronics....
I'll flip a coin and pick one.... or maybe buy/try them both...they're cheap.... looks like StewMac has the MOD for $16.00...plus a few $$ shipping. If I can find the other parts I need at StewMac....that may be the way to go....to save some shipping costs.
The volume issue might be a little different story....not quite so easy, and I might have to get my hands dirty.
I think this is the main issue....
sidekick_15_25r_35r_65r.pdf | |
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Looking at the schematic / parts list and looking at the amp....you can see that the "Volume" and "Gain" potentiometers are shown as "RA" --- I *believe* this is for "Reverse Audio/Log Taper", where the main "Master" volume is a "L" which I *believe* is for "Linear Taper"...... https://www.sixstringsupplies.co.uk/audio-or-linear-pots gives a great diagram of the difference....
You can see the difference between an "RA" and an "L" taper potentiometers. At the lowest numbers of the volume and gain control knob rotation (maybe 1 through 3), you are going to see dramatic changes in the "RA" potentiometers resistance. I believe this is why the sidekick goes from quiet to LOUD with very small changes of the "volume" and "gain" controls. The "Master" volume is a Linear Taper ...which is what I believe they all *should* be.....if all 3 controls were linear taper, I think you'd have more granular control over the amps volume and gain settings, but....it might sound weird to the human ear... people say that human hearing doesn't really like things to be 100% perfectly linear.
But maybe changing one....?
So that's going to be the first step..... finding 10K Linear POTS that will fit into the PCB board.....and have the correct shaft.
But maybe changing one....?
So that's going to be the first step..... finding 10K Linear POTS that will fit into the PCB board.....and have the correct shaft.
I found a pic on reverb that showed the main board, and the POTS.....but...it doesn't show the shaft....but at least now...I know what the board looks like, and kinda what I'm getting into .... looks like all the connections are hard soldered....this board might be kind of a booger to get out...
split shaft ....
Best guess ...this looks like the closest I could find..... I ordered 4 ...(just in case)..... at $1.35 I'll risk it... (but shipping/handling freekin' killed me!!!.... ouch....)
...and decided to order the MOD Reverb tank, just because the comes with standoffs, so I don't have to order them separately, but I might need to find a few wood screws to fit the tank with standoffs. I find it kind of weird that the tank is screwed directly to the bottom of the amp case ....
I know that there are other ways to get the volume under control on this amp.... using a "master volume" in the effects loop is always an option... like this , and this, but that can kind of limit the ability of actually using the effects loop. Lots of ways to accomplish this...but if a quick potentiometer replacement does the trick....to me that seems like the way to go.
Of course...if things go sideways....I can always gut the amp, and use the leftovers to tube it up.... :-)
To kind of (hopefully) verify that I'm on the correct path..... I went back to my current favorite Fender SS amp (The previously mentioned Harvard Reverb II) and looked at it's Volume / Gain/ Master Volume setup..... and...sure enough...
The "Volume" is a 50k A ---- "Gain" is a 50k RA --- and "Master" is a 50K L....
so at least dropping a different taper POT in the volume position isn't completely unheard of..... I think the L will work pretty good in there.
Part I
So the reverb tank I ordered came in....*cool* !!
....and..... I swap it out.....
....and.....it's pretty much exactly the same.....
*Crap*.
I was hoping that a new tank was all that was needed.....but ...the "replacement" tank ...was just that.... a replacement....not an improvement.
so...... do I try a different tank ? Cut my losses and buy a cheap reverb pedal? Build a surfy-bear ?
Hummmmm....decisions, decisions.....
So......I wound up doing a LOT of searching / investigation regarding the reverb on this amp.....and finally in one forum post, I found a guy who gave a real truthful opinion....and I tend to agree with him....(he sounded like he knows what good Fender reverb is supposed to sound like...)
It just stinks....it's bad.....a Fender amp with reverb like this is a shame.
So I started investigating .... why does the reverb stink ???
Fender knows how to make a good reverb circuit.... it's kind of one of the things they are known for.
Why is this one so bad??
The first thing I did was track down some comparable amps with "known good" reverb....and get a hold of the schematics....thinking that maybe it's a component mismatch....maybe they really pooched up a resistor value, or put a filter cap in the wrong place....something that even an idiot like me could see. Or maybe I had a bad component ??
And I think I found the answer...... as soon as you see it and compare it to some "known good" reverb circuits....it stands out like a sore thumb.
...and decided to order the MOD Reverb tank, just because the comes with standoffs, so I don't have to order them separately, but I might need to find a few wood screws to fit the tank with standoffs. I find it kind of weird that the tank is screwed directly to the bottom of the amp case ....
I know that there are other ways to get the volume under control on this amp.... using a "master volume" in the effects loop is always an option... like this , and this, but that can kind of limit the ability of actually using the effects loop. Lots of ways to accomplish this...but if a quick potentiometer replacement does the trick....to me that seems like the way to go.
Of course...if things go sideways....I can always gut the amp, and use the leftovers to tube it up.... :-)
To kind of (hopefully) verify that I'm on the correct path..... I went back to my current favorite Fender SS amp (The previously mentioned Harvard Reverb II) and looked at it's Volume / Gain/ Master Volume setup..... and...sure enough...
The "Volume" is a 50k A ---- "Gain" is a 50k RA --- and "Master" is a 50K L....
so at least dropping a different taper POT in the volume position isn't completely unheard of..... I think the L will work pretty good in there.
Part I
So the reverb tank I ordered came in....*cool* !!
....and..... I swap it out.....
....and.....it's pretty much exactly the same.....
*Crap*.
I was hoping that a new tank was all that was needed.....but ...the "replacement" tank ...was just that.... a replacement....not an improvement.
so...... do I try a different tank ? Cut my losses and buy a cheap reverb pedal? Build a surfy-bear ?
Hummmmm....decisions, decisions.....
So......I wound up doing a LOT of searching / investigation regarding the reverb on this amp.....and finally in one forum post, I found a guy who gave a real truthful opinion....and I tend to agree with him....(he sounded like he knows what good Fender reverb is supposed to sound like...)
It just stinks....it's bad.....a Fender amp with reverb like this is a shame.
So I started investigating .... why does the reverb stink ???
Fender knows how to make a good reverb circuit.... it's kind of one of the things they are known for.
Why is this one so bad??
The first thing I did was track down some comparable amps with "known good" reverb....and get a hold of the schematics....thinking that maybe it's a component mismatch....maybe they really pooched up a resistor value, or put a filter cap in the wrong place....something that even an idiot like me could see. Or maybe I had a bad component ??
And I think I found the answer...... as soon as you see it and compare it to some "known good" reverb circuits....it stands out like a sore thumb.
1. For this amp, they use IC's(Integrated circuits) for driving the reverb tank...
2. All IC's are M5218's
3. M5218's operate @ a max of 15-16 volts
4. The output (of the M5218's) is pretty much directly related to the supply voltage.
Driving a reverb tank (correctly) requires a pretty fair amount of current.... and I'm betting that these IC's just don't provide enough juice to really hit the reverb tank, and make those springs twist and shout....
Looking at "known good" reverb circuits..... I see "transistors" ...not IC's..... good 'ol PNP and NPN types...
A lot of these transistors are fed by 25-30+ volts.... and have significantly higher collector current and power ratings.
...in other words....they probably punch the reverb tank springs a lot harder than the IC's do.....
2. All IC's are M5218's
3. M5218's operate @ a max of 15-16 volts
4. The output (of the M5218's) is pretty much directly related to the supply voltage.
Driving a reverb tank (correctly) requires a pretty fair amount of current.... and I'm betting that these IC's just don't provide enough juice to really hit the reverb tank, and make those springs twist and shout....
Looking at "known good" reverb circuits..... I see "transistors" ...not IC's..... good 'ol PNP and NPN types...
A lot of these transistors are fed by 25-30+ volts.... and have significantly higher collector current and power ratings.
...in other words....they probably punch the reverb tank springs a lot harder than the IC's do.....
I think it's pretty easy to see that the transistors are running at some higher voltages....these two snips are from "known good" Fender Amps, with pretty highly praised reverb .....I own the one on the right...(a Harvard Reverb II), so I *know* what it sounds like.
Unfortunately...
This makes changing the reverb circuit in the amp difficult......*could* it be done ?? Sure (Ok.."Maybe"....I haven't even taken the board out of the amp yet..... on paper it looks like it could work) but all the time, effort, energy, and funds put into it would probably be a bit of a crap shoot..... if *everything* worked perfect and went exactly as planned ...you'd wind up with a good spring reverb.....and if *one thing* didn't work out or went sideways....you could very easily wind up with a pile of junk.
I'm starting to feel less and less guilty about maybe gutting this amp.....like here.
...of course......there is one way to test if my hypothesis about the IC's is true......
I have 1 amp that uses the transistors.....and it's reverb is great....
If I had a 2nd amp...made about the same time as the Sidekick Reverb 35, and that amp had transistors rather than IC's....that might be enough proof for me.......why do I want proof ?? Well...because now I'm curious .....
..........you should be able to see where this is going........
Unfortunately...
This makes changing the reverb circuit in the amp difficult......*could* it be done ?? Sure (Ok.."Maybe"....I haven't even taken the board out of the amp yet..... on paper it looks like it could work) but all the time, effort, energy, and funds put into it would probably be a bit of a crap shoot..... if *everything* worked perfect and went exactly as planned ...you'd wind up with a good spring reverb.....and if *one thing* didn't work out or went sideways....you could very easily wind up with a pile of junk.
I'm starting to feel less and less guilty about maybe gutting this amp.....like here.
...of course......there is one way to test if my hypothesis about the IC's is true......
I have 1 amp that uses the transistors.....and it's reverb is great....
If I had a 2nd amp...made about the same time as the Sidekick Reverb 35, and that amp had transistors rather than IC's....that might be enough proof for me.......why do I want proof ?? Well...because now I'm curious .....
..........you should be able to see where this is going........
...and what do ya' know.......two of them currently up for bid :-)
A little pricey by the time I add in shipping.....I'll keep my eye on both of them....maybe I can sneak in a low ball on the 2nd one.
From what I can see in the manual and schematic....the 30 is pretty close to the 35, except, no gain circuitry, only 1 channel , and no hard wired foot switch for the reverb.
The 30 looks like a "simpler" circuit..... in that there are fewer IC's in the tone stack, but other than that.....the circuits look quite similar. The 30 ALSO appears to use some sensible potentiometer taper types throughout the volume / tone stack (audio tapers and linear tapers, only 1 of the crazy RA taper pots on the "Presence"...)..
......the 30 may be the amp I was looking for.....
A little pricey by the time I add in shipping.....I'll keep my eye on both of them....maybe I can sneak in a low ball on the 2nd one.
From what I can see in the manual and schematic....the 30 is pretty close to the 35, except, no gain circuitry, only 1 channel , and no hard wired foot switch for the reverb.
The 30 looks like a "simpler" circuit..... in that there are fewer IC's in the tone stack, but other than that.....the circuits look quite similar. The 30 ALSO appears to use some sensible potentiometer taper types throughout the volume / tone stack (audio tapers and linear tapers, only 1 of the crazy RA taper pots on the "Presence"...)..
......the 30 may be the amp I was looking for.....
....and I was sidetracked by the 35 ........or would that be "Sidekicked" ??
So.....I'm going to hold up replacing the volume POT on the 35....until I see if the 30 is any better.....
If the 30 works for me.....I'll probably just get rid of the 35.....no sense putting any effort into it.
And....I got beat in 1 auction...for a really clean looking 30....and I missed my chance to low-ball the 2nd one... by half an hr..... who ends auctions on the half hour ???
Guess I'll just sit on the 35 for now.....and keep my eyes peeled for a 30 ... I'm sure one will pop up sooner or later....
...till then...there is a really nice looking Frontman 25r in red tolex that I have my eye on ..... :-)
I'm thinking about maybe building my own Princeton clone.....and the Sidekick 35r would be a great starting point...as would the Frontman 25.
So.....I'm going to hold up replacing the volume POT on the 35....until I see if the 30 is any better.....
If the 30 works for me.....I'll probably just get rid of the 35.....no sense putting any effort into it.
And....I got beat in 1 auction...for a really clean looking 30....and I missed my chance to low-ball the 2nd one... by half an hr..... who ends auctions on the half hour ???
Guess I'll just sit on the 35 for now.....and keep my eyes peeled for a 30 ... I'm sure one will pop up sooner or later....
...till then...there is a really nice looking Frontman 25r in red tolex that I have my eye on ..... :-)
I'm thinking about maybe building my own Princeton clone.....and the Sidekick 35r would be a great starting point...as would the Frontman 25.