Ceriatone Forum

Dumb question regarding one of Dr. Ika's mods:

Removing the .05uf cap at V1 -
Does that mean replace with wire, or break that connection?

Random thoughts:
I've had my OTS for about 2 years now and still not getting what I want out of it, though its getting close.
Currently running pine 2 x 12 diagonal cab with a pair of G12H30's. I found the EVM's to be somewhat sterile.
So I'm ready to try some mods. This amp is my first and only build.

I'm pretty happy with the OD tone, though I'm not getting the sustain/feedback thing much.
I have to play around with the PI, - I used the DCV method, but I'm going to try adjusting it by ear.
I'd like the clean to be more compressed, less stiff.
Some of Dr. Ika's mods seem to be the way to go.

Thanks again to Nik and many of you for helping me during the build.
I couldn't have done it without you!
Cheers,
Jon

If you change the LNFB on V1b then you ought to put the options on a switch. One option is 10Meg - cap- 10Meg, another is no FB. And of course you can change the cap value.

If you want to change the feel of the amp and loosen it look at changing the slope resistor as Doc has suggested many times.  I also like his treble bleed mod for OD, it allows you to set the clean channel brighter without compromising the OD tone too much.

And I don;t get the sustain/feedback OD thing either, though for me its not that important, I like the OD to be just a slightly driven clean, I have a 12AY7 in v2 and for me its better, less gain and distortion. I need to buy a load of different balanced PI tubes and spend some time trying to the get PI balanced properly though.

hywelg, thanks for the advice.
I'm going to tackle the mods one at a time so I can gauge the effect, and I want to start with the easiest ones.

So my question at the moment is: Do I replace the NFB cap with wire, or just remove it from the circuit?
Thanks

Hi,
just remove it from the circuit!
But better drill the chases near it and install the on/off switch as Hywel sugested !!!

Thank you Dr.  Yes, I'll put a switch.  Just wasn't sure if any signal should still flow through that path.
Your mod calls for a 3-way.  So I assume the tone with the other (470pf) cap is sort of half-way between the .05uf cap and no connection.  Is that right?

No need for 470pf, slightly noticeable difference. Just put an on/off.
It really works great.

Muchos Gracias, Dr.
I'll report my results/opinion in the next while.
My next gig isn't until next week, and I can only REALLY tell what's what after a gig or 2.
Like the EVM's - sounded good at bedroom levels, but got somewhat harsh when pushed a bit.
I had 2 of them - one was quite a bit darker sounding than the other.  At home, I thought the darker one had more mojo, but on the gig, I hated it.  The brighter one sounded more 'right', but in the end I didn't like the tone of either of them enough to put up with the weight.  (I'm getting old!).

Love your playing and tone, BTW.

Thank you Guitar…,

Try Celestion G12 K 100, it has big lows and nice mid/high tone. It is not expensive as well.

Good luck
Doc.

PickMaster,
Thanks for the speaker tip. I'm pretty happy with my pair of G12H30's, but still willing to experiment.

I performed the V1 NFB mod, and so far, I'm liking it a lot.
Ever since I got the amp, I couldn't decide if 'my' tone was with the Deep switch on or off.
I like the ballsyness when its on, but I always wished the boost had a lower center frequency.
Now, with the NFB mod, it makes the Deep setting sound less honkey and more useable.
Its just like you said - fatter, a bit more compressed, a bit more gain.  Its really making my Strat sing better.
Can't wait to try it at a gig.
Thank you.

I'm probably going to try the slope resistor mod next.  I've never seen those plain brown resistors before.
What are they called? and what wattage?  Can I substitute something I have laying around - like a regular 1/4 watt color coded type.

Probably Dale RN65D's though I think Nik only uses those on the plates?. Carbon film type, but you should really go for at least ½w in there, better still 1w.

Hywelg,
Thanks for the info.
I'll try to source those at my local electronics shop.
Otherwise, I'll have to order from Mouser or similar, in which case I'll have to figure out what else to order.
I don't really want to place an order and pay shipping for 1 resistor!!!!

PickMaster, THANK YOU.

Just got home from my first gig with the V1-NFB mod.
I'm very, very pleased with what its done to the  amp.
In short - my Strat grew a new set of bigger balls.
Another bonus was that the level differences - Deep on/off, PAB on/off were less drastic.

I thought I'd leave the deep on, but found myself switching back and forth for different songs.
I've done that on some other gigs, but now it just seems to work a lot better.
So now I have twice as many tones available as I would if I left the Deep switch in one position all the time.

What do you other OTS guys do with your Deep switch at gigs?

Hi Guitar,
I’m glad that you are happier with your tone now.
Best wishes   :)

I don't use the Deep (mid boost) switch on my OTS for any guitar or application. The sound is already full/

Dr. Ika,

I echo everything GuitarHack said abou the good changes due to the v1 mod.

Though

I am still wondering if all the fatness introduced contribute to the "fartiness" in the drive channel.

Would your drive stage mods fix that? Where those conceived particularly to compensate for the v1 changes? Or not necessarily?

Thanks again!
I am about 50% more driven to play gigs because of my amp.

Hi Captain,
Couple of suggestions: definitely change 150k resistor to 100k or less on X-line after 0,005mf cap. This would open a drive tone and volume.
Reduce drive gain a bit with the trim pot.
If you increase X-line’s 0,005mf cap to 0,01mf, drive will have more bass on it but try first above mod without cap change.
Also, if you increase big filter cap’s capacitance (add more capacitors) it will tighten amps overall bass response a little bit.
Cheers.

I've played a few gigs with just this one mod and the amp sounds better all around.
No flabby bass.  The OD is still a bit hard or stiff as it always was at gig volumes, but its not bad and certainly no worse than before the mod.

Played the last gig with Deep Off the whole time - never felt the need to switch it on.

I'd like to try some of the other mods - like the slope resistor.  Hywelg gave me some info on what parts to get, but when I went to Mouser to find it - there was a bewildering array of similar parts, so i had no clue what to order.

Does anyone here have any extra parts they'd like to sell?  That way I could be sure I'm getting the right items.

Sounds great thanks as always! Btw I have the bigger filter caps already. I still havent got around to changing the slope or the drive mods.

As regards parts for the various locations, the best bet is over at the Ampgarage. There are a number of BOM's in the files section that have Mouser part numbers and/or links directly to those parts. Best plan is always to get more than one of each item (resistors caps etc) and one value either siden to build up a stock of alternatives.

Very good idea to print out the layout and mark up any mods you do, and date them. I didn't do that from the outset and I wish I had.

Great advice. Thanks Hyweig.