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Post subject: Re: New Amp Build - Trainwreck Express Clone
Posted: Mon Jul 29, 2013 3:10 pm
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63supro wrote:
bluesky636 wrote:
Arnold Layne wrote:
Very tasty...Great looks, Great tone. Hey how'd the ankle heal up?


Thanks.

I still have problems with my foot swelling if I don't wear a compression stocking and am on my foot too much. People don't realize how long it takes for foot surgery of any complexity to heal. Its kind of a catch-22. You need to keep it elevated and stay off of it as much as possible, but you have to walk on it to get around.


I understand Bill. I had reconstruction on my left foot. They fused three joints into one bone. I have no side to side movement of that foot, but have no pain issues with it. It took me nine months just to walk properly and close to two years of rehab till it was 100%. It tales a long time and can be seriously painful through the healing process. The swelling eventually goes away.

Just keep at it.


Thanks man. Its just frustrating not to be able to walk my dogs in the park or due other things without the foot swelling. I have to get some slightly larger shoes because the doctor replaced the dead tendon with one that connects to the toes next to the big toe and now they just kind of splay out and press inside the shoe toe. That will help a lot.

I refused PT. Had it for a hip problem and hated it. :lol: I have almost full movement back just exercising the foot myself.

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Post subject: Re: New Amp Build - Trainwreck Express Clone
Posted: Mon Jul 29, 2013 7:06 pm
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That's great Bill. I'm sure the swelling will go. They moved some tendons on me too. My big toe drops down. Makes it a little tough to walk barefoot. I get by though. Mine was a congenital birth defect.

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Post subject: Re: New Amp Build - Trainwreck Express Clone
Posted: Mon Jul 29, 2013 9:27 pm
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63supro wrote:
That's great Bill. I'm sure the swelling will go. They moved some tendons on me too. My big toe drops down. Makes it a little tough to walk barefoot. I get by though. Mine was a congenital birth defect.


Big tendon (not Achilles tendon) in my foot had died. Don't ask me how. My doctor doesn't have a clue. Somehow the blood supply was cut off and the tissue was dead/dying. I have a photo my doc gave me. Looks like someone beat the tendon with a meat mallet. :shock:

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Post subject: Re: New Amp Build - Trainwreck Express Clone
Posted: Sun Aug 04, 2013 5:54 pm
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Just placed an order with Sweetwater for a full compliment of Celestion G12M Greenback reissues to go in my Crate 4x12 cab. Yeah, they are the made in China ones, but I can't afford the British made Heritage series. The only thing that made them affordable is that Sweetwater has a 2 year, no interest program going with their credit card. Also, I found this demo on line and they sound pretty sweet.


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Post subject: Re: New Amp Build - Trainwreck Express Clone
Posted: Fri Aug 09, 2013 3:36 pm
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Just finished installing and trying out my cab loaded with the Celestion G12M Greenback Reissues (16 ohm, 25 watts), I decided to go with the 16 ohm versions just for that old time Marshall grind. Holy $@!& Batman! These things have completely changed the sound of this amp. If they sound this good just out of the box, I can't wait to hear what they sound like after they have been fully broken in. They are that good sounding. Even though they are the Chinese built Greenbacks, they are well worth the money and definitely a better value than the British built versions. If this were a vintage Marshall cab (plywood instead of the pressed wood the Crate is made out of), I doubt you could tell the difference. Here is a shot of the wired up cab followed by a close up of one speaker.

Image

Image

I also made some final tweaks to the amp itself.

I had a slight, low level hum that could be heard with the volume turned all the way down (at normal levels it is not noticeable). I rearranged the grounds a little bit (all AC grounds to one bolt, all DC power supply grounds to a second bolt, and all signal grounds to a third bolt. The hum is still present, but reduced a little more.

Also, since I have been able to quiet the amp as much as possible, I went back and installed a DPDT bright switch with three selections: 100 pF bright cap, no bright cap, and a 250 pF bright cap. I tried a 500 pF bright cap but found that to be way too noisy. The 250 is just slightly noisier than the 100, but gives a nice boost further down in the mids.

The final (yes, I mean it this time :lol: ) schematic looks like this:

Image

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Last edited by bluesky636 on Thu Oct 17, 2013 3:28 pm, edited 3 times in total.

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Post subject: Re: New Amp Build - Trainwreck Express Clone
Posted: Fri Aug 09, 2013 4:10 pm
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Very cool, be sure to update the video you made, I'd really like to hear how it sounds with the new speakers and :lol: FINAL :lol: tweaks.

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Post subject: Re: New Amp Build - Trainwreck Express Clone
Posted: Fri Aug 09, 2013 4:30 pm
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Arnold Layne wrote:
Very cool, be sure to update the video you made, I'd really like to hear how it sounds with the new speakers and :lol: FINAL :lol: tweaks.


Well, if you can tolerate my lousy playing, I can do that fairly soon. If you want to REALLY hear how good the amp and cab sound, I'll have to talk my instructor into coming back over. I'm sure some beer and pizza will help. :lol: :lol: :lol: :lol:

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Post subject: Re: New Amp Build - Trainwreck Express Clone
Posted: Fri Aug 09, 2013 6:34 pm
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Cool! I agree with you about the Chinese versions of some of the Celestion speakers being as good or indistinguishably close, and great, value-wise. I got the Chinese versions of the V30s and they are also awesome. Congrats on the killer head and cab. 8)

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Post subject: Re: New Amp Build - Trainwreck Express Clone
Posted: Fri Aug 09, 2013 8:36 pm
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shimmilou wrote:
Cool! I agree with you about the Chinese versions of some of the Celestion speakers being as good or indistinguishably close, and great, value-wise. I got the Chinese versions of the V30s and they are also awesome. Congrats on the killer head and cab. 8)


Thanks. :D

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Post subject: Re: New Amp Build - Trainwreck Express Clone
Posted: Sat Aug 10, 2013 7:25 am
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I agree. The Chinese V30s sound pretty darned close. It's possible they may not last as long but at a quarter of the price who really cares if they don't?

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Post subject: Re: New Amp Build - Trainwreck Express Clone
Posted: Sat Aug 10, 2013 11:24 am
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Amazing thread.

Some rules for circuit design (you've probably heard them)

1) Your oscillator design will not oscillate. Everything else will.
2) Your $80 power transformer will blow - thus saving the 50 cent fuse.
3) If you can build a TW and make it work, you can build anything.

I humbly bow to you.

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Post subject: Re: New Amp Build - Trainwreck Express Clone
Posted: Sat Aug 10, 2013 1:09 pm
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mhowell wrote:
Amazing thread.

Some rules for circuit design (you've probably heard them)

1) Your oscillator design will not oscillate. Everything else will.
2) Your $80 power transformer will blow - thus saving the 50 cent fuse.
3) If you can build a TW and make it work, you can build anything.

I humbly bow to you.


:lol: :lol: :lol: :lol:

Thanks. :D

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Post subject: Re: New Amp Build - Trainwreck Express Clone
Posted: Sun Aug 11, 2013 9:39 pm
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bluesky636 wrote:
mhowell wrote:
Amazing thread.

Some rules for circuit design (you've probably heard them)

1) Your oscillator design will not oscillate. Everything else will.
2) Your $80 power transformer will blow - thus saving the 50 cent fuse.
3) If you can build a TW and make it work, you can build anything.

I humbly bow to you.


:lol: :lol: :lol: :lol:

Thanks. :D

1 & 2 are jokes. Number 3 is no Shih Tzu. Taming a high gain amp is a bear. Trainwrecks are aptly named because if you don't know what you're doing that's what you'll end up with.

Also left out a rule. 4) The finest looking solder joint will be the one that's cold.

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Post subject: Re: New Amp Build - Trainwreck Express Clone
Posted: Sat Sep 07, 2013 4:16 pm
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Had an interesting time this afternoon with the Wrecking Ball.

I gathered the amp up and took it over to Action Music, a small independent guitar dealer in Falls Church, VA. They specialize in vintage equipment (electric and acoustic guitars and amps) a select new equipment.

http://www.actionguitar.com/

I introduced myself to the owner and explained to him what I have been doing and asked if someone in the shop would be willing to test drive the amp. He said that he would be glad to do it after another customer who was auditioning a couple of amps was finished.

After about 15 minutes, he plugged my amp into an Orange 4x12 cab loaded with Celestion G12Hs and then plugged a late vintage Gibson Les Paul Standard (I was too nervous to ask what the guitar exactly was :lol: ). I told him a little about the amp and what the design was. He then set all the controls to 12 noon except for the volume control which he set to max! He then let loose. :shock:

I was thrilled that the amp did not collapse into screaming/squealing oscillation (I had briefly tested it with all controls dimed and was confident it would hold together) and was amazed at how loud it was. He then twisted all the controls from high to low as he played (volume still maxed out) to get a feel for how the amp responded. Then he turned it down to about 5 and did the same thing. He played the amp like this for about 20 minutes as several customers and employees watched and listened (and didn't run for cover). When he finished, I noticed smiles on everyone's faces (which I took as a good sign) as he apologized for blowing everyone's head off in the small shop.

His verdict?

"It's a really good sounding amp".

His comments/criticisms?

1. The tone controls need more range to them. They are good at levels below about 6, but when the volume is dimed, they lose their effectiveness.

2. The bright switch was a little to heavy handed.

2. The amp has too much gain in the front end.

3. The amp is too loud for today's market.

We then talked for another 30 minutes about different approaches to alleviate his concerns.

I'm going to reexamine the tone stack design. I evaluated several different designs while building and testing the amp ranging from a Fender Blackface type stack to a 59 Bassman stack (what is in the amp now), and a Trainwreck Express type stack (similar to the Blackface, but not quite). I'll take a look at these again to see how they respond at different volume settings.

The current bright switch uses a DPDT switch with center = off, up = a 100 pF cap, and down = a 250 pF cap. I personally don't like the 250 pF cap as although it gives a nice midrange boost, it brings the noise floor up too much. I had tried a 50-off-100 configuration earlier but I was still having noise problems then and abandoned the bright switch entirely. After I solved the noise issues I settled on the 100-off-250 set up. I think I'll look at the earlier version again.

Reducing the gain can be done a number of ways. The Action Music owner suggested just adding a low gain input. Early on, I built a switchable bypass cap for V1. I didn't like it as it caused a hum when the cap was switched out. I could also just try a lower gain tube in V1 or V2. Several good choices.

As for the volume, I don't like master volumes. A PPIMV would be a good choice for this amp, but it reduces the effectiveness of the negative feedback and presence control. I may take a look at the Hall Variable Voltage Regulator (VVR) which is popular with this type amp.

http://www.hallamplification.com/main.html?src=%2F#2,2

Stay tuned for more high gain fun.

Note: I was very nervous going to Action Music with the amp today, but am really glad I did. The owner was very nice to take the time to try out the amp. He had some really good suggestions and was very supportive of what I was doing. Even though we didn't open up the amp, it thought the build quality was really good and that the amp was very professional looking. I'll definitely go back after I am able to come up with some solutions to his suggestions. :D

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Post subject: Re: New Amp Build - Trainwreck Express Clone
Posted: Sat Sep 07, 2013 4:28 pm
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bluesky636 wrote:
1. The tone controls need more range to them. They are good at levels below about 6, but when the volume is dimed, they lose their effectiveness.


This is often the case, even with Leo's original designs. However, extending the boost range may be detrimental to the S/N ratio.

bluesky636 wrote:
2. The amp has too much gain in the front end.


If you haven't already given them a go, you might try 5751's and/or 12AY7's in the V1 and/or V2 sockets.

Arjay

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