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Topic: Evans changes over the years |
Brad Sarno
From:
St. Louis, MO USA
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Posted 26 Jul 2004 12:33 pm |
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I was wondering if anyone owning an older Derrell Stephens era (or older) Evans knows what type of capacitors are in the preamp section. I hear so much about how the newer Evans amps just dont have the magic of the older ones. I've been looking inside of a brand new Evans HV preamp and I've also been analyzing the EQ curves.
My first and most glaring observation is that the tone capacitors are ALL the very very cheapest lo-grade ceramic types. Even the bass control tone cap's are cheap ceramics. This is generally a no-no in musical and audio gear. Sometimes ceramics are cool in the midrange and treble because of the grainy distortion they create. Perhaps since there are jfets in there, the ceramic cap distortion adds to the character. I may have to experiment with it and see. Even the coupling caps are pretty cheap. My first impression is that there is serious cost-cutting at work that would majorly downgrade the audio quality, but maybe it's actually some very intentional tone-based choices. Hmmm...
I'm wondering if the old Evans also used the ceramic caps on all of the tone sections or some of them. Has anyone recapped a newer Evans with good caps to see what it sounds like?
Also, what's up with that treble control? Were they always so brutal? On the audio analysis of the preamp, the treble will simply not cut at all. At zero it's about flat. At .5 it begins to get real bright. At 1 it's about 20dB boosted. At 3 it's over 30dB boosted at 16kHz like a ramp up to the stars. I've never seen a treble control so extreme and totally out of range. All of the usable range I found on steel was between zero and .7. Set on even just 1 was way too bright. The high treble also has a kind of glassy, brittle, thin quality which I'm thinking may be the cheesy ceramic tone capacitors. The jfets should sound much warmer and sweeter based on my experience with other jfet based amps.
Other than the cheap cap's and the wacky treble control, the Evans preamp is voiced really nicely for steel. The general tone/voice is real cool sounding. It seems that the tone could be much better if the tone (especially the bass and mid) cap's were of better quality and if that treble control were re-designed to put it in a usable, more tweakable range.
Anyone???
Brad Sarno |
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Larry Hamilton
From:
Amarillo,Tx
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Posted 26 Jul 2004 1:59 pm
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Brad, I play an Evans E-200 that as about 4 years old or so. I dojh't know anything about the electronics, but I do know what you are talking about with the highs. I play a LeGrandell. When I had the stock 19.5s in it I could use a little treble and I sounded great. NOw i have TT 18.5's and I had to add bass and body and cut the treble to 0 with the Expand on and the Boost off, and I still ave a killer tone. I tweek it almost daily according to the way my ears hear that day. I have been thinking about installing a pair of TT 19.5's just to see what happens. Once again I'm sorry I'm not educated in electronics, but I hope my observations might help in your research.
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Keep pickin', Larry |
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Ivan Posa
From:
Hamilton, New Zealand
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Posted 26 Jul 2004 2:16 pm
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Brad, I have found the treble control on my SE 200 to be extreme and had my amp tech do some minor mods to try and make it more useable. His comments were similar to yours. I obtained the older FET 500 schematics and we compared the tone circuits. The older circuits were more conventional and well liked by most players and we could not see why Evans went to the extreme treble they are currently using. I will be most interested in any improvements you find to be useful as I really like the SE 200 with the Deltalite speaker...IP
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Gene H. Brown
From:
Whitehorse, Yukon Territory, Canada
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Posted 26 Jul 2004 5:38 pm
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Hi Brad,
I know what you mean man, I had an Evans SE200 brand new and I just could not play through it with the extreme treble, so I went back to the Fender Twin, some people love em.
Gene |
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Kevin Hatton
From:
Buffalo, N.Y.
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Posted 26 Jul 2004 7:04 pm
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| Same observation here Brad. The FET 500 that I had could cut diamonds with the treble. Thats one reasom that I sold it. Very interesting analysis. |
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Brad Sarno
From:
St. Louis, MO USA
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Posted 27 Jul 2004 5:13 am
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I've heard so many people make these kinds of comments on treble of the the Evans circuit. That's why I got the Evans preamp. I really want to see why such a classic amp can also have such a problem with the treble control design. Also, the cheap capacitors were a surprise to me. Sometimes you'll see gear that's made by engineers who understand electronics, but aren't hip to the sonic qualities of different varieties of components. As far as cap's go, there are ceramic, tantalum, aluminum, polyester (mylar) film, polystyrene film, film and foil, paper in oil and foil, and the list goes on. They ALL have their own sound color.
I and a couple of others are looking into a possible mod to get the treble into a useful control range. I'm also going to upgrade the signal and tone capacitors as it's pretty obvious they need major improvement from what's in there. More later....
Brad Sarno |
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Brad Sarno
From:
St. Louis, MO USA
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Posted 27 Jul 2004 10:59 am
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Well I've just finished a few things on the Evans HV pre. The tone capacitors are all changed from ceramic to good film types. Huge improvement overall, huge. The bass and midrange are much cleaner, fuller, and warmer, as you would expect since ceramics generally sound crappy down there. The top end is also smoother and less brittle and plasticky sounding.
To get the treble range under control, my first attempt at fixing that issue was to take the 1meg pot and replace it with a 50k audio pot. This pot value seems to give you control over the useful range of treble and gets rid of all that excess high boosting that comes with the 1meg pot. The treble range on the old pot that was between zero and about 1.5, is now between zero and 7 or 8. Where I once had the treble knob set at .5, now it's at about 4 or 5 and the sweep is smooth with no jumps or kinks. I'm not sure yet if this will cause any other problems, but so far so good.
Still tweaking,
Brad Sarno |
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Ivan Posa
From:
Hamilton, New Zealand
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Posted 27 Jul 2004 12:45 pm
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Great stuff Brad, I watch your posts here with great interest. I will be upgrading my SE200 with your suggestions....IP
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Doug Earnest
From:
Branson, MO USA
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Posted 27 Jul 2004 1:58 pm
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Brad, it was good to visit with you in Branson. As I have stated before, I bet a new Sarno steel amp would be a mighty fine one.......now get to it!!!!
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Doug Earnest
The only Zum Keyless U12, Fender Cyber Twin
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Brad Sarno
From:
St. Louis, MO USA
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Posted 27 Jul 2004 3:07 pm
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Hey Doug, good to see you down there too! Pretty fun steel show. Yea, I may just have to head down that road eventually and develop a steel amp. I'll have to sell a few more black boxes first. All the amp needs to be is a combination of all the best aspects of a Session 400, a Webb, an Evans, a Twin, a Sho-Bud, a Standel, a Walker, and maybe a couple of others. Piece of cake!
Brad Sarno |
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Darvin Willhoite
From:
Roxton, Tx. USA
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Posted 27 Jul 2004 6:06 pm
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And it needs to be the size of a Dallas phone book and only weigh 15 lbs.
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Darvin Willhoite
Riva Ridge Recording
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Doug Earnest
From:
Branson, MO USA
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Posted 27 Jul 2004 6:30 pm
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| The size of an Evans small cabinet would be just fine. Also a head only version. Brad is just the guy to make it happen, he has the brains and the ears. Sorry for the topic drift...... |
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Jon Light
From:
Saugerties, NY
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Posted 27 Jul 2004 6:41 pm
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| Most interesting, Brad. I have a Stephens era 500 Custom. Predictably, ditto on all the treble comments. Now that I've got a little bit of tech work under my belt, it would be interesting to consider some of the cap upgrades you're talkig about. |
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David Nugent
From:
Gum Spring, Va.
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Posted 28 Jul 2004 3:29 am
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Brad,
Do you have an approximate cost for the modifications, including labor? |
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David Mullis
From:
Rock Hill, SC
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Posted 28 Jul 2004 5:54 am
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| I'll agree on the treble being extreme, but, my resolution for that on my Stephens built FET 500 small cab is to NOT turn the treble past 3, I usually keep it on 2. The highs don't sound bad, and everything else sounds GREAT! The same goes for my FET 500 HV. I had a tech go through the HV a while back and undo some rube goldberg mods. He didn't mention anything about any cheap components, actually quite the opposite. Maybe one of these days I'll get him to go through the small cab as well, just for maintenance purposes. |
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Brad Sarno
From:
St. Louis, MO USA
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Posted 28 Jul 2004 9:05 am
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David, I'm not there yet. I'm just learning about this piece. Hopefully it'll be a simple mod involving just a few cap's and maybe a pot. I put in some questions directly to Evans Amps and hopefully they'll enlighten me as to what the hell is up with this crazy treble control and all the cheezy cap's. For all I know, they may have what they consider very good reasons for it.
With the new 50k audio pot in the treble control, I can now have very good control over the amount of treble. On this preamp, the "Body" control is a knob and not a switch. If you turn it way to the right, it shelves out the highs. Using a bit of that and the treble knob, I can get it real balanced.
Also, with the ceramic cap's gone and decent film cap's in their place, the whole overall sound is more clean and full and punchy. I really can't imagine that they would believe that ceramic cap's on the bass control were a good sonic choice. But, I've been proven wrong many times before so I'm open to the possibility that they have "good" reasons. It still looks like cost cutting or tonal ignorance to me.
More to come,
Brad |
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Lee Baucum
From:
McAllen, Texas (Extreme South) The Final Frontier
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Posted 28 Jul 2004 10:17 am
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Brad - Have you tried contacting Derrell? He posts on here sometimes. He could probably tell you what he was putting in the FET 500 LV models he was building.
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Lee, from South Texas
Down On The Rio Grande
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Brad Sarno
From:
St. Louis, MO USA
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Posted 28 Jul 2004 10:35 am
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Lee, I found his email, I hope it's current. I asked him about these issues. I hope he responds.
Thanks,
Brad
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Brad Sarno
From:
St. Louis, MO USA
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Posted 28 Jul 2004 4:43 pm
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Well I got to speak with Derrell Stephens about this issue. He said that he has been comfortable with the the hot treble issue because he uses the tone control on the guitar to roll the highs back. My ZB has no tone control so that didn't help me. I described my change of the tone pot value from 1meg Audio taper (stock) to 50k Audio taper. He said that's fine to help expand the lower range of the treble sweep. But he also adivsed me on one other resistor change to let me get away with the lower value pot. Very simple. I've done it and the treble knob now works much more like you'd want for steel. You can sweep from zero to 10 and it never gets so ungodly bright as before.
The other issue was about the types and quality of capacitors used in the signal path and tone sections. Derrell used precision film capacitors, as I suspected. The modern era Evans seem to be using ceramic cap's. That is a critical factor that has EVERYTHING to do with sound quality. Ceramic cap's are simply not good sounding in the tone sections or interstage coupling. They have a relatively choked, grainy, thin sound. Film cap's are the choice for audio. There are exceptions, but generally this is the case.
So, the Evans mod is forming. So far it involves replacing the treble pot with a 50k Audio pot and putting about 1meg (this can vary a bit but should be at least 680k) of resistance on the leg of the pot that sees the smaller (270p) cap. This gets the treble control into range and keeps the circuit impedance right.
The other factor is pretty much replacing every little tan ceramic cap in the preamp section with a film type of the same value. I had some silver mica cap's for some of the smaller values. I need to order more to complete the job. I haven't yet done all of them, but I did the coupling caps and the main tone caps. They're all quality film types now, just as the Derrel Stephens era Evans amps had.
It sounds much better now.....
Brad Sarno
[This message was edited by Brad Sarno on 28 July 2004 at 05:54 PM.] |
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Larry Hamilton
From:
Amarillo,Tx
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Posted 28 Jul 2004 5:50 pm
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Brad, I am so glad that we electronically challanged have someone like you to watch out for us. THANKS! When you get a mod kit figured out, who do we get to put it in? I hope instructions come with so my local repairman can do it. Thanks again for your time. I am watching this thread pretty close. Very good subject.
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Keep pickin', Larry |
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Lee Baucum
From:
McAllen, Texas (Extreme South) The Final Frontier
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Posted 28 Jul 2004 6:16 pm
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Great work, Brad. Derrell built my amp for me back in the mid-1980's. I guess he built them right. I've never had a complaint. I have noticed the treble issue. I just never go past 2 on that control.
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Lee, from South Texas
Down On The Rio Grande
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Jeff Hogsten
From:
Flatwoods Ky USA
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Posted 28 Jul 2004 10:03 pm
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| years ago I worked at a music store and sold several HV fet 500s when Jim still had the co best amp I ever played, when it was stolen I bout a newer L/V not the same amp not even close |
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Brad Sarno
From:
St. Louis, MO USA
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Posted 29 Jul 2004 8:20 am
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From what I can gather, the newer Evans amps that have left some people feeling dissapointed are easily upgradeable to what people loved about the Derrell Stephens era amps. The differences are slight but in my opinion, critical. The main factor is the cap upgrade. This will HUGELY improve the fidelity, fatness, and sweetness of the newer models.
The other is the treble mod. The treble issue was there all along, even in the old models. This mod is for those who want to be able to get that useable treble range that is normally between 0 and 1.5 expanded so that you can turn the knob all the way giving more precision in dialing in the "right" amount of treble.
I'm going to start ordering parts and making some little kits. For the technical minded, I'll just post the list so you can do it yourself. It's just a few pretty simple parts replacement.
More again later,
Brad |
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David Mullis
From:
Rock Hill, SC
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Posted 29 Jul 2004 2:51 pm
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That's great Brad. Both of my amps are Stephens era amps. I've talked to him before myself and he is one of the nicest guys you'd ever want to talk to. I only wish I had either taken notes or recorded the conversation because I forgot a lot of what he told me about working on these amps. Please keep us posted on the mod kit, I may be interested in the Treble mod.
Take Care
David |
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Jon Light
From:
Saugerties, NY
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Posted 29 Jul 2004 3:15 pm
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Hey Brad--do you have any working experience with the models with the "bite" and "expand" toggles? I was wondering what they specifically are switching between and whether pots could replace the switches---I'm a believer in variable adjustment in place of switches wherever practical.
---and let me add that I'm aware (I think) that there are models that do indeed have pots instead of switches---I'd guess that this is exactly what I'm talking about?[This message was edited by Jon Light on 29 July 2004 at 04:17 PM.] |
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