#1
So, I have this Yamaha GA-10, 3 knob, two channel SS amp, 10 watts, and I feel like throwing a bunch of metal film resistors in it.

My only questions are, would it do anything? And can I replace the 1/8th watt resistors(tiny as all specks can be) with 1/4 watt resistors?

I'm expecting my metal film resistors some time next week, so it'll be a while...The amp doesn't sound half bad as is.

Also, tell me what else I can upgrade while I'm in there...heres some pics of the insides.







#2
i honestly would not bother at all, just save up and buy a new amp
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#3
yeah you can replace the 1/8th with 1/4 watt. I have no idea what the difference is going to be between metal film and whatever is in there right now, but im willing to bet its not going to be noticeable enough for the effort
#5
Quote by GS LEAD 5
He's probably doing it as a project, IIRC he has a Trace Elliot for a main amp.


Yeah, it's just to help me get better at making stuff work after I mod them, since I fail at it right now.

Still tweaking that Trace Elliot, it just as so many friken tones you can pull from it it's hard to find one that works with the DS-1. I think the DS-1 is just to nasily sounding...I'll fix that though in the coming weeks.

It may do nothing, it may make the gain tighter and better, who knows.
#6
Quote by ethan_hanus
So, I have this Yamaha GA-10, 3 knob, two channel SS amp, 10 watts, and I feel like throwing a bunch of metal film resistors in it.

My only questions are, would it do anything? And can I replace the 1/8th watt resistors(tiny as all specks can be) with 1/4 watt resistors?

I'm expecting my metal film resistors some time next week, so it'll be a while...The amp doesn't sound half bad as is.

Also, tell me what else I can upgrade while I'm in there...heres some pics of the insides.
]


Doubt very much it will make much difference as the tolerance of the other components (capacitors, pots, transistors, etc) are all probably already greater than the resistors anyway.

Personally, if it were me I'd spend my money and time drinking beers. After a few of those your amp and everything you play will sound excellent for a while.
#7
Quote by Phoenix V
Doubt very much it will make much difference as the tolerance of the other components (capacitors, pots, transistors, etc) are all probably already greater than the resistors anyway.

Personally, if it were me I'd spend my money and time drinking beers. After a few of those your amp and everything you play will sound excellent for a while.


Well, if it works in upgrading pedals, it'll work in a crap SS amp. Plus, the ones in there are 5% variance, metal film are 1% variance.

I'll do plenty of drinking on my 21st here in a few weeks.
#8
replace all the little bridge rectifiers with hexfreds or sic schotky's

replace all the small signal op amps with burr brown opa's.

replace all the power mosfets with umm...awesomefets.

replace all the capacitors with nichicon kg gold throughs.

replace all the ceramic caps with polystyerene or polypropelene

replace all the resistors with mil spec vishays

replace all the pots with sealed rv2s.

the end.
Prs se Holcomb is the answer
Last edited by AcousticMirror at Aug 26, 2011,
#11
Quote by ethan_hanus
Well, if it works in upgrading pedals, it'll work in a crap SS amp. Plus, the ones in there are 5% variance, metal film are 1% variance.

I'll do plenty of drinking on my 21st here in a few weeks.


I know what % tolerance metal films are in comparison to carbon films.

Still think if you hear a difference it will be more because you think you should be after you put all your will, sweat and effort into it. But in reality the difference will be subtle, if at all.

What Acousticmirror is suggesting will make some difference. But then if you're going to do all that, might as well just replace everything collectively.

Have fun.
#12
Quote by Phoenix V
I know what % tolerance metal films are in comparison to carbon films.

Still think if you hear a difference it will be more because you think you should be after you put all your will, sweat and effort into it. But in reality the difference will be subtle, if at all.

What Acousticmirror is suggesting will make some difference. But then if you're going to do all that, might as well just replace everything collectively.

Have fun.


it's just for shits and giggles right.

resistors are almost last on the list.

40 dollar op maps first.
Prs se Holcomb is the answer
#13
Quote by AcousticMirror
it's just for shits and giggles right.

resistors are almost last on the list.

40 dollar op maps first.



I'm not gonna spend $40 on this amp, it's not even worth that...

Anyways, I just put some germanium diodes in place of the old diodes, and it sounds a million times better, much clearer, and warmer, but the speaker sucks...some idiot put a 8 watt speaker in a 10 watt amp...it says Yamaha so I assume Yamaha is the idiot in this case. I get lots of speaker distortion past 5 on the volume, and it's shrilly, no low end at all.
#14
You could replace the solid state chassis with a tubular one.
Quote by Most_Triumphant
Depends, I don't know what pickups go good with plywood. EMGs will make it sound like every other EMG guitar though.

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it needs a silver flakes
and sara underwood
#15
It's not going to have much low end with a small speaker. Tbh, I would more likely do what y2k11hmmm? said (seriously, wtf is that username?).
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#16
What was the big difference? Germanium diodes? I'll try that on mine! I disconnected the clipping diodes on my squier sp-10 and it gave it a smoother almost fuzzy distortion. Pretty neat. Also, see if you can get a little more gain out of it. I know my amp doesn't really get overdriven enough unless you put a high output humbucker into it.
#17
Quote by LeviMan_2001
What was the big difference? Germanium diodes? I'll try that on mine! I disconnected the clipping diodes on my squier sp-10 and it gave it a smoother almost fuzzy distortion. Pretty neat. Also, see if you can get a little more gain out of it. I know my amp doesn't really get overdriven enough unless you put a high output humbucker into it.



Yeah, Germanium diodes, they are what they used before they had silicon or any of the other materials they use in diodes, gives a more natural and warmer clipping sound. They are very easy to break, since they are just a glass tube thing.

It made everything sound warmer, boosted the volume output a tad, gain still sounds like crap though, that's prolly due to the OP amp.
#18
Alrighty, I has an update for ya'll. I just put as many metal film resistors in the amp that I could, and replaced 3 caps, and it sounds soo much better. I've concluded that the stock speaker was crap, and caused alot of the breakup in the tone. So I disconnected the speaker, put a jack on it, and ran this little 10 watt bugger into my 480 watt 4x12. I was surprised at how loud it was, and how good it sounded. I also put a orange LED in there, cause I could.

Who says you can't polish a turd? Ive done it way to many times.







Some sound clippies so ya'll can hear what this monster sounds like.

Clean: http://profile.ultimate-guitar.com/ethan_hanus/music/all/play1041700

Dirty: http://profile.ultimate-guitar.com/ethan_hanus/music/all/play1041701
#20
Quote by LeviMan_2001
That sounds pretty beast! What would you rank the mods in order of biggest change to smallest?


Speaker hands down is the biggest mod to any crap SS amp, the speakers are so crappy I wouldn't even use them to test sound with.

Next would be the germanium diodes, really smoothed out the gain.

Next would the be the caps, the stock caps had horrible tolerances, putting caps with +/- value of 5% or less, even if it's just a few, helps with the tightness.

Last would be the resistors, I don't think they changed much, except maybe added some tightness and responsiveness to it, since they are a much tighter value than the 5% ones.
#21
Another update. I just finished ordering all the final parts for this amp. Going to replace all the caps, and the speaker. I also checked out the output transistor chip, and it's rated at 35 watts exactly...explains why it was so loud though my 4x12 with the volume at 5. Makes me wonder why the amp is rated at 10 watts, but has a 8 watt speaker, and a 35 watt output transistor, makes no sense.

I got a Jenson MOD 8, 20 watt 8 inch speaker at 4 ohms, so I'll be building a new cab for the amp.

Here's what I got.
1 VISHAY-RODERSTEIN MKP-1837 Film Capacitor 0.047uf 100VAC / 160VDC 1%VISROD-72941
2 VISHAY-RODERSTEIN MKP-1837 Film Capacitor 0.1uf 100VAC / 160VDC 1%VISROD-72943
2 VISHAY-RODERSTEIN MKP-1837 Film Capacitor 0.01 uf 100VAC / 160VDC 1%VISROD-72206
1 Elna Cerafine Capacitor 0.47 uF 50 V 5 X 11 mmELNA-72662
3 Elna Cerafine Capacitor 1.0uF / 50V, ROA Series, 5x11ELNA-72663
1 Elna Cerafine Capacitor 2.2uF / 50VDC, ROA Series 5x11ELNA-74628
3 Elna Cerafine Capacitor 10uF 16V 5x11 mmELNA-72667
1 Elna Cerafine Capacitor 22uF / 50V, ROA Series, 10x12.5ELNA-72671
1 Elna Cerafine Capacitor 100uF 50V 12.5x20 mmELNA-72681
1 Elna Cerafine Capacitor 47uF 35V 10x12.5 mmELNA-72674
1 Silver Mica Capacitors_029-54409 100pf 500vSMICA-029-54409
2 Nichicon-018-Series FG 2200uf / 16v D(16 mm) x H(25 mm)NICHICON-72587
1 .22 Panasonic Radial Film Capacitors 50V 5%
1 .47uf Panasonic Radial Film Capacitors 50V 5%
1 Silver Mica 100pf
1 OPA2134PA
3 8 Pin Machine Tooled IC Socket
1 Jensen MOD8-20 20W 8" Speaker

All in all, the mods in total cost me about $70-$80. Not bad for a 35 watt, half way decent sounding SS practice amp in my opinion. We'll just have to wait and see how it sounds with all the mods.

Last mod I'm gonna do is add a gain control pot, because there is no gain control on this amp, so I'm gonna have to find the resistor that controls the gain and put a pot in it's place.
#23
Quote by LeviMan_2001
35 watt? I'm pretty sure that thing is 10 watt. But I think it's cool to see people goin out there and trying new stuff.


No, it's a 35 watt output transistor, the amp says it's 10 watts, but that's because it's limited by the original 8 watt speaker. Looked at the data sheet for the transistor, says 35 watts max.

Same with my Ibanez Acoustic amp, it has a way higher rated output transistor than the amp is rated for.

I bet this is going to sound nice though, it's such a simple circuit too.
#26
Quote by LeviMan_2001
You might be gettin into the whole peak vs. rms thing. I kind of doubt it's in fact 35 watts.


I'll open it up tomorrow and post the transistor chip data sheet, maybe I am, but I saw 35 watt max output for that specific chip model.
#27
it really shouldn't matter what the max output of the chip is.

it'll only depend on how much the chip is set to make.
Prs se Holcomb is the answer
#28
Quote by AcousticMirror
it really shouldn't matter what the max output of the chip is.

it'll only depend on how much the chip is set to make.


Yeah, but plugged into the 4x12, it's not 10 watts, it's much much too loud.It's almost as loud as putting my 700 watt Trace Elliot on 1, almost.

Here's the data sheet. The exact chip is TDA2030A 8E6321 Sing

http://www.datasheetcatalog.org/datasheet/stmicroelectronics/1459.pdf

If it helps any, it has 2200 uf 16 volt filter caps I'm guessing in there.
#30
Quote by ethan_hanus
No, it's a 35 watt output transistor, the amp says it's 10 watts, but that's because it's limited by the original 8 watt speaker. Looked at the data sheet for the transistor, says 35 watts max.

Same with my Ibanez Acoustic amp, it has a way higher rated output transistor than the amp is rated for.

I bet this is going to sound nice though, it's such a simple circuit too.


Mainly because class A and A/B amps require more input power to what they can produce as output.

They are inherently in-efficient. The transistors are biased to operate within whats called their 'linear' range. Most of what they conduct ends up as heat, and some comes out as the actual sound. So the perception is that they end up being 'oversized'.

I'm not going to go into all the theory here, but if you're interested take the time to read up or google about the efficiency ratings of class A , A/B amps.

This link is a good basic start. http://sound.westhost.com/efficiency.htm
#31
Quote by Phoenix V
Mainly because class A and A/B amps require more input power to what they can produce as output.

They are inherently in-efficient. The transistors are biased to operate within whats called their 'linear' range. Most of what they conduct ends up as heat, and some comes out as the actual sound. So the perception is that they end up being 'oversized'.

I'm not going to go into all the theory here, but if you're interested take the time to read up or google about the efficiency ratings of class A , A/B amps.

This link is a good basic start. http://sound.westhost.com/efficiency.htm


This actually makes more sense. So the chip has to be higher output because most of it is burned off as heat. Makes sense.

Still, it's loud as eff for a 10 watt SS amp.
#32
Ok, some more updates. I added the OPA 2134 chip in, replaced 3 caps for now, and built my new speaker cab with the 8 inch Jenson Mod speaker in there. Gutted my Ibanez ACA10 amp and mounted the speaker in there. Sounds pretty good, can't wait till I get the rest of the caps in, prolly will sound much better then.





And some sound clippies.

Clean: http://profile.ultimate-guitar.com/ethan_hanus/music/all/play1044000
Distortion: http://profile.ultimate-guitar.com/ethan_hanus/music/all/play1044001
Pushed clean...like you would with a tube amp, sounds remarkable good: http://profile.ultimate-guitar.com/ethan_hanus/music/all/play1044002
#35
New updates...sorta...I took the old Yamaha cab, and chopped it so it's now a head...like a mini head...and I tore the grill cloth off the Ibanez, and then stretched it out back on my new cab...which was the Ibanez cab. I also strengthened the cab, and drilled holes so the speaker can breath, and help with rattle.

I'm still waiting on the rest of my parts from Parts Connexion, 8 days I've been waiting...starting to get pissed. Anyways, here's some pics of what I've done.

The head is held together using dowel pins, and black silicon....yeah, idk why, it's just what I had lying around....we'll see how long it lasts.