Supercharging a V8

[jrcorp]

Thank God you hopped in Verne, I don't think I had a shot with that question. Transformers scare me.

[Verne Andru]

My goodness, you scare easy jrcorp LOL.

Nothing to fear. A transformer is the most basic of components. It's a series of iron plates wrapped in wire a predetermined gauge and number of turns. There is one set of input wires and there can be multiple pairs of output wires. Beyond the 2 primaries outputs, others can be placed at strategic points in the windings [say 1/2 way] according to what you need done to the signal. That's where the math comes in. A transformer becomes hot because the current goes through the wire and part of the signal is dispersed as heat. The only way they "break" is if the winding gets broken at any point due to being cut or burnt. Since they are designed to dissipate heat, it usually takes a fair bit of excess applied for more than a few seconds to start to see any adverse effects. You usually smell and/or see something burning.

[FinkBrau]

Originally Posted by Verne Andru

Welcome to the forum Pierre. You could try contacting Crate [now owned by LOUD] and asking them how to convert it to run on 230V. IIRC it was designed [or indications show it was designed] to be easily adapted to different power situations but Crate service - which are very good IME - are the people to ask.

Fuses are designed to blow before any significant damage happens to the electronics, so there is a very good chance you may not need much more than a new fuse. Transformers tend to spew smoke and show signs of burning when they go, as the windings will melt. Hammond makes all sorts of replacement transformers and are very well priced, so I'd check with them if you do need a replacement. Usually other components like resistors/capacitors will go long before you melt a transformer. If you didn't smell anything or see anything that appears burnt, you could be okay.

Good luck!

Thanks for the reply! In fact I don't think I burned anything else but the fuse, but my guess is that if I want to use my amp on 230V I'll have to swap the transformer because it has only a 110V input... But I'll try to contact Crate, as you suggested!

[jrcorp]

Originally Posted by Verne Andru

My goodness, you scare easy jrcorp LOL.

Haha well it's just a component that I'm not familiar with, and for some reason being a big wire-wrapped hunk of metal that's involved with power is a little intimidating I guess?

Just started playing through the V5 again. My first attempt at a head cab awhile back was a flop, but that was my first project with wood and I've built a birdhouse now so it's worth another shot. I like the sound of the amp but there's still a few mods to go. There's a weird buzz coming from the cab too so I'll probably take a look next time I pop out the chassis.

In other news, I tried to jump on a V18 locally but no luck. My other tube amp is a HRDx, and I definitely don't need that kind of power. So I feel like an approximately 15 watt amp would do the job. I've been on the fence about selling the Fender forever but I've already modded it so that's money sunk.

[Wayne2]

I got a question about how I put weatherstripping on the back panel to stop it from buzzing. I still haven't figured out how to resize images, but if you want to see it look here. The brand of weatherstripping is "Frost King" if that's important.

While I had the back panel off I went back to the JJ 12AT7. I was also planning to do the piggyback resistor mod but when I opened the bag from RadioShack I realized I hadn't actually bought them months ago, only looked at them in the store and bought other crap. Plenty of alligator clips though.

[Verne Andru]

I'm assuming the weather stripping is to stop the back panel from vibrating? If so, what you use isn't important. What's important is to put something between the back panel and the chassis so it sits tight and can't move. I put mine around the inside part of the the panel board along the edge so when it's put back in place the stripping gets sandwiched between the panel and the chassis.

[Wayne2]

Originally Posted by Verne Andru

I'm assuming the weather stripping is to stop the back panel from vibrating? If so, what you use isn't important. What's important is to put something between the back panel and the chassis so it sits tight and can't move. I put mine around the inside part of the the panel board along the edge so when it's put back in place the stripping gets sandwiched between the panel and the chassis.

Sorry, I meant I received a question about how I did it. The link goes to a picture about how it's done. Works well.

edit -
I did the piggyback resistor mod today. Soldered in a 1K resistor each over the 1.5K R10 and R15 resistors. It's not my most beautiful work but the amp fired up and sounds good. Picture of piggyback resistor mod here. Note how close the one leg of C13 is to R15. That's why I put the resistor on the other side.

I like it so far... we'll see in a few weeks. Kind of sounds calmer, like the preamp tube is now taking the brunt of that midrange hump and smoothing it out. I tried it with both humbuckers and single coils.

It wasn't as hard as I had anticipated. I wish I had done this one sooner. It's reversible too.

[Wayne2]

Here is an inline pic and the product information.

Piggybacked resistors:
These are from RadioShack
1K ohm 1/2W 5% Carbon Film Resistor pk/5
Model: 271-1118 | Catalog #: 271-1118
$1.19

I soldered them next to R10 and R15 (1.5K each)

Using the resistors in parallel formula:
1/Rt = 1/Ra + 1/Rb
1/Rt = 1/1.5 + 1/1
1/Rt = 2/3 + 3/3
1/Rt = 5/3
Rt = 3/5

Rt = 600 ohms.

The main thing again is to look around where you're soldering to avoid shorts. C13 was a little too close and the protective glue on that one leg wasn't done too well, so I put the resistor on the far side of R15 to keep it safe.

[jrcorp]

Wayne, is that just a continuation of modding the amp by adding components in parallel? Your soldering looks good as always, definitely better than mine.

I've been having a blast playing my V5, just using my cheap Washburn with JB/Jazz pickups and coil splitting. The variety of tones to be had from just fiddling with a few knobs is amazing - I set the amp's tone at around 2-3 o'cloc and the volume at the same, just before break-up. Then between the knobs and coil splitting on the guitar, I have all kinds of options. I've actually used the tone knobs on a guitar more in the last week than ever before, and I feel as though I'm getting the hang of finding different tones. Not only that, I've been practicing more than I have in so long.

I may have to look into a little weatherstripping or something similar, as I have noticed a little buzzing and assume that's the culprit. Finally, there's a V16 for sale about 2 hours away that I would love to jump on if I could only sell something first and make the drive. This poor V5 deserves some more love too - with all the fun I'm having, I think I ought to get around to that head cab and then a better tone stack and an effects loop. Maybe if I man up a bit I'll try tackling some bigger projects like Verne did with his amps.

[Wayne2]

The piggyback resistor idea was Verne's, based on stuff some guys tried with the VC-508. I'm not sure but I think Verne pulled the board on his and desoldered the resistors properly, putting new ones in. The piggyback method is a not quite so proper but it's faster and easier because all you have to do to get to them is remove the back panel. (don't forget to turn off and unplug the amp!)

The schematic is here: http://www.verneandru.com/WebApp/Dow...-schematic.pdf

I'm intrigued by that V16 too, if only for the built-in spring reverb and more power. Jump on it if you want it. I was scanning Craigslist and saw the Palomino 212 cab at a good price. Hesitated and lost. Haven't seen one since at any price.

Yes a functional guitar tone knob is great with these amps. Especially with the C9 mod I did (increasing the cap value) I have a nice clear bell-like open top end but it can be too biting and my strat with the big tone cap rolls it off nicely. Yesterday I was playing with the amp's tone knob at 10 and low volume, and using the guitar tone I was able to get a nice tone that reminded me of the strat and deluxe reverb I played at the store.

The weatherstripping project is not hard. Hardest part is finding it in Home Depot. I linked to a picture a few posts ago. The resistor mods are more difficult but worth it.

What have you done with your V5 so far?

[Wayne2]

Here is an inline pic of the back panel weatherstripping:

[Wayne2]

 

Originally Posted by jrcorp

I've been having a blast playing my V5, just using my cheap Washburn with JB/Jazz pickups and coil splitting. The variety of tones to be had from just fiddling with a few knobs is amazing - I set the amp's tone at around 2-3 o'cloc and the volume at the same, just before break-up. Then between the knobs and coil splitting on the guitar, I have all kinds of options. I've actually used the tone knobs on a guitar more in the last week than ever before, and I feel as though I'm getting the hang of finding different tones. Not only that, I've been practicing more than I have in so long.

 

Good job! That's the whole point of all this, right? I'm as guilty as anyone of obsessing over extraneous crap when I should be playing.

[jrcorp]

Originally Posted by Wayne2

...I'm intrigued by that V16 too, if only for the built-in spring reverb and more power. Jump on it if you want it. I was scanning Craigslist and saw the Palomino 212 cab at a good price. Hesitated and lost. Haven't seen one since at any price.

Yes a functional guitar tone knob is great with these amps. Especially with the C9 mod I did (increasing the cap value) I have a nice clear bell-like open top end but it can be too biting and my strat with the big tone cap rolls it off nicely. Yesterday I was playing with the amp's tone knob at 10 and low volume, and using the guitar tone I was able to get a nice tone that reminded me of the strat and deluxe reverb I played at the store.

The weatherstripping project is not hard. Hardest part is finding it in Home Depot. I linked to a picture a few posts ago. The resistor mods are more difficult but worth it.

What have you done with your V5 so far?

I like what I've heard and read of the V16, but my only hesitation would be a lack of resources on people modding the amp... and money. The owner offered to ship for an extra $40, but I would rather not spend even that much (though I know it's worth it).

I appreciate the info regarding the weatherstripping. There's a 24-hour Walmart and a Home Depot in the same plaza where I work, so that project shouldn't be difficult when I decide to go for it. I am hoping to build a head cab out of pine though, so maybe it wouldn't be necessary.

My experience modding the V5 has been basically looking at Verne's V8 mods and trying to adapt them to my amp. Looking back at it, I may have been a fool, but I tried to calculate values for components in the V5 based on his replacements and go from there. From what I can recall, I've done all the mods on the schematic except the tone stack, which I plan on soon. I should mention that my soldering isn't at all as clean as what I've seen of yours. My time has been spent all over the place, but once I get settled and ready for music projects I'll put together a parts list and get to work.

Originally Posted by Wayne2

Good job! That's the whole point of all this, right? I'm as guilty as anyone of obsessing over extraneous crap when I should be playing.

I agree entirely. That's what makes this amp so enjoyable to me, I think - the simplicity. That and knowing all the work I've put into it myself. It's funny you mentioned getting Deluxe Reverb tones from a V8 - I'm hoping to sell a Hot Rod Deluxe and that's where my funds for a V16 would come from. I may try finding something that works for me or building a tweed Deluxe (another simple amp) down the road.

[Wayne2]

I'd forgotten that you did all the intermediate mods. Good going. How did you get those electrolytic caps out?

There's also a new V32 on Ebay now. Probably last chance for that. I dimly remember them from the store as really loud.

[jrcorp]

Originally Posted by Wayne2

I'd forgotten that you did all the intermediate mods. Good going. How did you get those electrolytic caps out?

There's also a new V32 on Ebay now. Probably last chance for that. I dimly remember them from the store as really loud.

I remember going at that goopy crap for a long time, probably with a small screwdriver or two. Once that's gone I don't think it's too bad. I think I actually broke a small electronics type of flathead, ha. Don't let it scare you off, just take it slow and steady.

Thanks for the heads up on the V32. Unless there's a good chance or getting a range or tones at low volume and it's light, I don't think it's for me. I'm hoping for something around 15W and light, probably a 112 combo but maybe a head. I want to eventually make a 112 cab too.

[Wayne2]

Originally Posted by jrcorp

I remember going at that goopy crap for a long time, probably with a small screwdriver or two. Once that's gone I don't think it's too bad. I think I actually broke a small electronics type of flathead, ha. Don't let it scare you off, just take it slow and steady.

Thanks for the heads up on the V32. Unless there's a good chance or getting a range or tones at low volume and it's light, I don't think it's for me. I'm hoping for something around 15W and light, probably a 112 combo but maybe a head. I want to eventually make a 112 cab too.

Just another heads up, I got sick of looking at overpriced 112 cabs and ended up ordering a Kustom V50 1x12 from MF for $199 tonight. Might be more watts than necessary but the price is right. They also have the regular 50 (single channel, no effects loop) for $199 and the V100 for $299. (which is heavier and louder, but might as well mention. It has vibrato and tremolo, which is tempting). If it's ridiculous loud and I hate it, I figure I can sell it or turn it into a cabinet right? But I have a feeling it will be fine.

[jrcorp]

Oh no, there's a used VC508 on sale at the local GC for around $50! How awesome would that be, having another amp to mod. I think that one is more closely related to the V8 too? It has a line out stock that can be used with a stereo cable for an effects loop.

[Wayne2]

 

Originally Posted by jrcorp

Oh no, there's a used VC508 on sale at the local GC for around $50!

 

you know what you have to do

[jrcorp]

Originally Posted by Wayne2

you know what you have to do

Absolutely, I have to swing by and grab it before anyone else has a chance. I know it's spending $60 or so, but I'm not even questioning whether to go. I really want to work out some nice mods for these amps and maybe use them to learn about working with tube amps in general. Playing around with different tone circuits would be fun, maybe adding reverb of some kind, etc. I can't wait.

...just kidding, it sold already!

[jrcorp]

Paging Verne...

I've been reading up on modding different amps lately as I'm trying to make up my mind on my Hot Rod Deluxe. On BillM's site, I found a page talking about replacing op amps on the Super Champ XD. He mentions two that I wasn't familiar with - the 5532 and 2132 - to replace the TL072. On other pages, he also mentions the 4560 and states that it and the TL072 can be swapped. I did a little searching and found some discussion of op amps, including the 2134 as well as others... this audiophile page mentions tons of them. BillM mentioned that he could tell some slight differences in tone.

Assuming pinouts are the same, is it worth upgrading to some of these "hi-fi" op amps? I don't know if that's the right term, and I notice through searching Mouser and reading that audio thread, some of the op amps are called "high speed," and there's mention of a need to mess with the circuit to accomodate certain models. I just noticed that at least the 5532's can be had for about the price of the Excaliburs I had bought for the Crate. I figure that for our purposes in guitar amps, the slight differences aren't worth the cost.

There's a cool thread on that forum which shall not be named, involving a test of 14 different op amps in a Timmy. Here's the soundclick, good stuff but I doubt I can hear any appreciable difference. I realize that the pros and cons of op amps used in effects are probably different than those for amp circuits.

[Verne Andru]

There are quite a few different opamps that are pin compatible. If you're up to experimenting, replace the V8's opamp with a socket then you can try out different versions to see which you like best.

The VC508 is the same circuit as the V8 but it has an 8" speaker instead of a 10". That would have been a great score for $50.

[Gtrbear]

Hello everyone. I would like to thank everyone for sharing their knowledge about the Crate V8 Palomino, especially Verne Andru! I found this thread when I was researching why/how the gain pot on my (made in Vietnam) V8 "went bad." Basically, it sounded like it was set on "10" even when it was not. Tapping/whacking the top of the gain knob temporarily resolved the problem. I ultimately replaced all 3 pots with parts from Mouser for $2.40 + shipping.

I also read this entire thread and decided to do many of Verne Andru's simpler mods (op amp replacement, C2, C9 & C12 removal & resistor "piggybacking"). I just completed the mods and must say that the tone of my V8 has improved quite a bit! The clean tone especially is definitely improved. There is no "boxiness" any longer and the amp just sounds like it is bigger. I didn't find the stock tone control to be horrible, but it is definitely improved now after the mods. I have no problem getting a respectable AC/DC tone now ("For Those About To Rock...").

One thing I found curious was that the C9 removal was, to my ears at least, not an improvement. I found that it made the amp far too dark for my taste. I put C9 back and that worked better for me. However, there is still a "harshness" that is present, especially with some gain applied (perhaps 10:00 and higher). I was curious if anyone has replaced C9 with a smaller value cap rather than removing it entirely. It would seem to me that this might be a "happy median" for me between having the original value C9 and removing it entirely.

One thing left - get a Y cable and run a boost pedal in the fx loop...

[Wayne2]

Originally Posted by Gtrbear

One thing I found curious was that the C9 removal was, to my ears at least, not an improvement. I found that it made the amp far too dark for my taste. I put C9 back and that worked better for me. However, there is still a "harshness" that is present, especially with some gain applied (perhaps 10:00 and higher). I was curious if anyone has replaced C9 with a smaller value cap rather than removing it entirely. It would seem to me that this might be a "happy median" for me between having the original value C9 and removing it entirely.

I went my own way on C9. If I understand correctly (a big "if" ), C9's purpose within the tone stack is to act as a high pass filter, and its effect is most noticeable as you turn the tone knob clockwise to get scooped mids. C11 and P2 are a low pass filter, and in combination with C9 they give you mid cut capability, which is what the amp needs.

If C9 is gone, the tone becomes muddy when you turn clockwise because all the highs are lost. If C9 is 100 pF (stock), you get a thin piercing top end and scooped mids but you can't really scoop far enough without it becoming muddy. By increasing it to 250 pF, you can crank the tone knob all the way clockwise and still retain clarity, but the harsh mids are tamed, and the bass is actually improved because you can turn it up without the ear-raping mids. On some of my pickups this setting sounds too trebly, but I can dial it out with the tone knob on the guitar.

If C9 were still there, I could have tried piggybacking a 150 pF cap to get 250 pF total. As it was I had already removed C9, so I just used a whole new cap. I used a silver mica cap.

IMO if you were to reduce the value of C9, all you would do is create a situation where the tippy top high frequencies were going through but you'd still lose clarity if you attempted to use the mid-cutting capabilities of the tone stack's clockwise half.

[Gtrbear]

Thanks, Wayne2 - I am going to give your suggestions a try!

[yoyodunno]

Just did the removal of C9 today, sounds much better IMO! The shrillness is basically gone and the gain is much more useable. Here's some noodling to show the tone with gain at around 10 o'clock, tone at 9 o'clock, volume 8 o'clock:
http://soundcloud.com/andrew-blowe/p...ith-c9-removed