Output Transformer Upgrade Test / Comparison - Trainwreck Express Clone
Вставка
- Опубліковано 18 жов 2024
- A while back I rebuilt an old Hammond AO-29 organ amplifier into a Trainwreck Express clone. I used the original Output Transformer intended for 6V6 power tubes and about 15 watts of output. This amp is much hotter running 6L6's and pushing perhaps 40-50 watts in adjustable fixed bias. I believe I am fairly heavily overworking this OT and the performance of the amp has been suffering. So I bought an Output Transformer from a Fender Hot Rod Deluxe that is much more appropriately rated and wanted to share the comparison.
Hit "Subscribe" for more videos!
www.youtube.com...
Grab some cool merch and support my videos:
Tip Jar - paypal.me/kleydejong
kley-de-jongs-...
If you wish to support my videos please visit my patreon page at / kleydejong .
Links:
My Soldering Iron - amzn.to/2PAVwUb
My Audio Interface - amzn.to/3kcJKuo
My Studio Studio Monitors - amzn.to/3dtSFpH
My Picks - amzn.to/2NobVdB
My Favorite Pedal - amzn.to/3k5OJN9
My Favorite Mic - amzn.to/2NfhDPe
My Camera - amzn.to/3qCD8I2
My Favorite Strat Pickups - amzn.to/3dsLC0H
The old Hammond sounded cool but the beefier HRD Transformer opened the doors to a bigger sound. The best thing about those HR and Bluez Deluxe amps is the transformers they use. I had a bluez deluxe gutted but kept the Transformers using a reverb trans an extra valve and a choke handwired to make a simple 1 channel with reverb tweed 1x12 and It blows a new Fender Away. I believe that you can use 5881 valves to replace 6v6s without a new transforner but what you did was build a 40w super tone making machine, great job, great sound!
I’m building an Express clone as we speak. I have a very rare NOS Stancor OT that Ken Fisher used on the first few Express builds. This amp will be special! What’s unique about this amp is how the amp transitions from overdriven to clean with your guitar’s volume control with very little volume loss.
I replaced the stock OT in my AO35 that I turned into an 18 watt with a VVR. Used a Hammond 1750 PA. The stock one just wasn’t giving up the goods as well as the new Hammond. I hope to find a use for the old one at some point. Your build sounds fantastic!
Sounds to me like there is more snap to the attack of the note and it somehow sounds a bit more "open". Seems like a worthwhile upgrade!
See if Mercury Transformers will loan you one of their similarly rated units to try for a demo and see if you hear further improvements. I bet you would!
I've been considering that Fender OT for a while now but I noticed that the pri impedance is 4K plate to plate. It's interesting that if you look up the power out vs. load impedance (RCA tube manual) for 6L6, 7027A, 6V6 nearly all put out max power at 6.6 to 8K impedance and power drops significantly at 4K. It would be interesting to try an 8 ohm speaker on the 4 ohm tap and see what the difference is if any. The level will change since the voltage out is different and the volume on the amp should be adjusted accordingly. Great videos, thanks! I happen to have a Hot Rod Deville on the bench and will try to take a measurement on it to confirm the 4K primary impedance.
Good move, on the new transformer. Without going into maths, or transformer power rating, 6V6 & 6L6 like to see different 'reflected impedance' measurement; from the output transformer. [Uncle Doug & others cover this, in existing videos] With proper Reflect Imp, the transformer does it's best work & valves/tubes work more efficiently. Going a bit over spec, on the output transformer power rating, is usually a good move; as well
Ive had an ao29 chassis for a number of months and having a hard time deciding what to build with it. Leaning toward an express. Yours sounds incredible. Id be running 6v6 or possibpy el84. I dont mind lower wattage. That being said im taking heed of your ot comments..
Very surprising the tone remained almost the same. Which points to power section design being more important than OT specs IMO. How would you say the specs compared? Rating wise, you were overworking it, but what about the other specs? Where they otherwise similar?
Cool, thanks
Great tone upgrade. I am currently looking at a Trainwreck Liverpool reproduction 7.5k primary impedance OT by pacific transformers to be used with with two 6l6gc tubes in a push-pull config. I am struggling a bit with my understanding of this so I am just going to go for it. If all else fails I can just buy the PT for the trainwreck and make one of those!
6L6GC pair is like 60W max, those tubes are crazy
Did you have any problems with oscillation with the point to point design ?
No I have not
How did you work out your primary impedance into your reflected speaker output impedance?
You should have shortened the playing and used the Strat with humbucker in it. Express + Humbuckers is a good combination.
Im thinking of rebuilding an amp of mine. It has 2x El84 and 3x 12ax7, what circuit do you recommend? Im leaning towards a dumble type but i dont know what specific amp. I dont wanna buy new transformers so im keep the tube output tubes as is. Thanks
I love my Dumble. I don't know if 2x El84 would have enough headroom to work ideally with that circuit. But it would be a fun amp! I say go for it.
Try a vox stylecAC 15 type design, it will get the max out of EL84. Orange used to make a 15watt AD15 combo which was excellent 2xecc83, 2xel84, 1x Gz34 it blew a marshall away for sheer compression and sustain all in a 1x10" combo...like an old Fender Harvard but much much louder.
Hammond 5:28
Fender 5:52
Hey my output transformer went out in my fender hot rod deville 3 and I can’t find a replacement is there any universal trans that I can use?
www.amplifiedparts.com/products/transformer-hammond-output-replacement-fender
@@KleyDeJong I have build quite a few amps with Hammond Transformers, they perform very good, and are readily available.
Hammond are really inexpensive as well! My friend picked up a replacement for his 1960s bassman for about 80 Canadian dollars shipped.
@@TobiasC-mg4zk That is for sure not really expensive.
You should only get 10 to 12 watts max with 2 6v6 tubes in SE in push pull about 18
Or you could put in 2 at 6l6-5881 tubes for about 18 -24 watts in SE depending on output trans and how big the power supply is you need at least 120ma
how do you measure that 50-60 watts with that 15 watt transformer ? what is your B voltage ? and the ohm in that transformer is 8K .
Hi, can you tell what books or literature is available on output transformers?
London Power in Canada wrote a whole series of tube amp books, and if you are mostly interested in Power Amps ´Principles of Power´ could be a good choice.
Hi.
Just got a dsl20 head today. Sounded awesome. But I was just trying to unplug my foot switch from the back of the amp, but unplugged the speaker cable instead. It was 30 seconds before I realized what I had done. The amp was on the clean channel, volume 3, gain 2. Now it seem the distortion channel doesn't sound quite as good. Like it's lost its 'chug.' What kind of damage could occur based on what I've described. I'm literally freaking the f out. So pissed at myself for making such a careless mistake. I don't want to send this amp back as they are extremely hard to get right now. I didn't hear any funny noise, no funny smell, no hissing or popping sounds. If I did damage the amp what should I look for?
Any update on this?
@@robimiara7444 I'm taking it to a authorized repair guy. It still sounds ok. Just not as good. Will keep you updated.
That will kill an output transformer
Why would the output transformer plates wires cause oscillations and squealing wired in a certain order but the other way it won't cause oscillations and squealing? Both output transformer plates wires should be matched and the same impedance, not imbalanced.
It's related to the feedback signal either creating a positive or negative feedback loop. Positive feedback sends the signal from the preamp to the OT secondary which then tries to go back into the power tube plates. Not good squealing mess. Negative feedback sends the signal through the circuit as designed. Then the output is fed back into the middle to suppress, stabilize, and change eq response.
@@KleyDeJong this only will happen if the amplifier has a presence pot negative feedback path because most amplifiers don't have a presence control so this output transformer squealing issue won't happen, it will only happen with amplifiers that have a presence control?
@@waynegram8907 If the amp has a presence or depth control, those are tone controls in the nfb loop. But some amps have nfb without placing a presence or depth control in the loop.
@@KleyDeJong yes true, what I'm saying is reversing the output transformer plates wires will only matter if an amplifier has NFB loop? If an amplifier doesn't have an NFB loop then it doesn't matter about the orientation of the output transformer plates wires?
@@waynegram8907 Yes that's right.
Гошррз ООО инеапрю?@
Ок хх