TW Express with reverb

[adamG]

Guys,

I'm going to buid it with Deluxe Reverb, which is 12AT7 and half of 12AX7. Totally, it would be 4 preamp tubes.
Do you think it's possible and worth of effort ?
If so, then where shall I implement it in circuit ?
Also, I consider a choke instead of big 25W resistor. Do you think it does make sens? How would it impact on amp sound ?
What choke should I apply ?
Many questions:) Sorry. 

Thanks in advance.

Regards,

Adam

[tubenit]

Maybe this layout posted at TAG would be useful to you?  I personally would use a 1M dwell pot instead of the 1M dwell resistor. You could install the dwell pot on the back panel since it's seldom adjusted.

However, this isn't the same as the TW Express but may give you some idea in insertion point.

Look at Sluckey's excellent Tweed Deluxe Reverb schematic for the reverb insertion point in comparison.

With respect, Tubenit

[tubenit]

OK, I just found this idea for a TrainWreck with reverb that I drew up some yrs ago.  Not sure when?  I haven't ever built it so consider it a DRAFT idea.

There is an ExpressSCH editable version attached. 

I typically have done the reverb insertion just prior to the entrance of the LTPI as shown in this schematic.  I've been happy with that.  However, it may be better to have the insertion point prior to V3a as in Sluckey's Tweed Deluxe Reverb?   Maybe Sluckey will comment on that for you?

You can experiment with 500p to .001 range caps going into the dwell pot or dwell resistor.

With respect, Tubenit

*  I got to thinking about this.  I honestly would probably try to put the reverb insertion just prior to the LTPI instead of prior to V3a.  Two reasons:  1)  I don't need a lot of reverb to be happy and this method has worked successfully for me previously and 2) the TrainWreck is a fairly high gain amp and I'd rather have the overdrive reverbed then the reverb overdriven.  Meaning I'd like it further down the signal chain.

NOT saying you should do it this way, but that's probably how I'd approach it.

[adamG]

Thank you T. very much:)

May I ask for another issue assistance?
MV...I like this idea. As I heard, this amp is approx.35W, so MV would be a good one for quieter playing, right?
Also, there's something what might be a nice solution. A switch or better relay that could bypass V2A tube.
I thought to myself that in this way I'd keep clean as more Fendery sound, than with bypass off, V2A is activated and more gain is back;)
What do you think about it?

Thank you in advance.

Regards,

Adam

[tubenit]

I've never built, played or had interest in a Trainwreck.  I guess you could add a PPIMV? I guess you might be able to bypass V2a? However, those mods may make it sound nothing like a Trainwreck?

I'd probably post those questions on the Amp Garage & see what they say. Maybe someone there has tried something similar?

http://ampgarage.com/forum/viewforum.php?f=1


With respect, Tubenit

[MFowler]

The Express uses a 300mA power transformer with matching OT for 50 watts.

For master volume in the Express go with the PPIMV also labelled as Lar-Mar from Metro-Forum.


I used to use a dual 250kA pot but switched to dual 250KL pot which in the opinion of many sounds better and was originally suggested by Larry and Mark on their Lar-Mar PPIMV

[adamG]

I guess you might be able to bypass V2a? However, those mods may make it sound nothing like a Trainwreck?

No, not that way. My point is to keep Trainwreck as much as possible, but I'd like to have both TW and kind of Fendery clean input/stage with bypass:)
With switching on/off I'd get both TW and Fendery("soft" and its beauty).
Does it make sens?

Regards,

Adam

[adamG]

The Express uses a 300mA power transformer with matching OT for 50 watts.

There's info in the net of TW Express 30-35W with OT 6.6K, but you mentioned 50W. Why? Could you explain, please?
Also, why is necessary to provide such a big amount 300mA?

Thanks in advance.

Regards,

Adam

[DummyLoad]

I guess you might be able to bypass V2a? However, those mods may make it sound nothing like a Trainwreck?

No, not that way. My point is to keep Trainwreck as much as possible, but I'd like to have both TW and kind of Fendery clean input/stage with bypass:)
With switching on/off I'd get both TW and Fendery("soft" and its beauty).
Does it make sens?

Regards,

Adam

speaking from extensive experimenting experience with the TW preamp: trying to switch the second or third gain stage in/out is prone to gross instability.


IMO, the best place to inject reverb would be after TMBV stack.


--pete

[adamG]

IMO, the best place to inject reverb would be after TMBV stack.

Thank you Pete.

Do you mean this place as on att.schematic? It is quite familiar with Sluckey's Deluxe, regardless minor changes.
My basic idea was to utilize second half of V2 and to add V3 as reverb. I just feel, the amp is a little bit too "raw" without loop or reverb:)
Do you think it is unwise to mod this famous circuit and build it as it is?
Please, be honest.

Regards,

Adam

[DummyLoad]

suggest that you build it as ken fische designed it. also suggest that you follow the TAG or ceriatone layouts. it's a finicky amp. fiddle with the value of the 150k load/grid-leak for v2 to tune it. also, plate R bypass caps can help tame it. dress the leads to the tube sockets neat and short.

--pete

[Ed_Chambley]

The Express uses a 300mA power transformer with matching OT for 50 watts.

There's info in the net of TW Express 30-35W with OT 6.6K, but you mentioned 50W. Why? Could you explain, please?
Also, why is necessary to provide such a big amount 300mA?

Thanks in advance.

Regards,

Adam

You primary impedance on your OT is not 3.3K or 3.4K always for EL34.  Look at you data sheets.  Many factors go into determining what will work and what you desire.  Your reflected impedance is tied to Pout as well as voltages.  For instance, old Baldwin Organs with around 300 VDC on the Plates normally had a 10,000K primary with 6V6Gt.  Raise the voltages to a 5E3 Deluxe and you find 8K.  Raise it more like a Blackface Deluxe and you are looking at 6k6 primary.  Then look at the KT66 GEC data sheet.  Some build it with a 4K like a Bassman, but to me the tube sounds more Fendery with a tad more bottom girth.  Raise it to a 6k6 primary and you get a nice JTM45 with stronger upper mids.  Even with the same values.  These changes are not nothing compared to changing a speaker load from a 16 ohm tap to an 8 ohm tap.


Here we are speaking of selection for tone or overdrive as well as NFB which which plays a role.  There are books, not paragraphs written on the subject.  Experimentation is the best to gain understanding.  Do not think because your clean out is less this amp will be quieter.  It is loud as sh*t and needs to be played this way.  Get lower SPL speakers.  93 DB if possible.


The reason for the seeming high MA on the HT is the Wreck is prone to oscillation and if you build it as I posted you chances of success will greatly improve.  Edcor has a PT that is really good for the build and doesn't break the bank. A lot of guys who build will get the minimum Power Transformer that is required.  If you are a blues guy, you may like this, but the Wreck will not.  This amp cannot sag, trust me.  I built a bomb with one.  Changed the PT and changed a few resistors and it woke up.


Dummyload's and others advice is spot on from my experience.  I have never built one, even a preamp version, that sounded right at fire up.  They have a enormous fill, but can easily be flat and sterile.  This is normally a oscillation you cannot hear causing it.  It cancels phase and hopefully you have a Oscilloscope to find this.  If not, it can take days to weeks and still you may not know where it is.  Do not try a small chassis.  I have never built one that sounded correct, except the replica, in a smaller than a 8 x 19 x 2 aluminum, heavy aluminum.  The Transformer needs this.


I know the feeling about Reverb, but this is really not a verb amp.  I have done it, but mine does not have it.  I did install a Mosfet based loop lifted from a Dirty Shirley Freidman, but I have also successfully added a Metro Loop too.  SS loops.  To all you tube guys, your pedals have ss components, however I do like tube color in low gain loops.  Mine is bone stock as built in the PDF I posted.  No loop and I will use a Klon at unity volume.  The amp likes Delay in front and doesn't like chorus.  A buffer is nice and a tone bender with the Germanium Transistors are nice with single coils.  Buckers are too over the top with any fuzz.


The gluing together of the mica caps is no joke in the Express.  Since Ken Fisher was well above me in knowledge, I have no idea why or how he thought of it.  I do know what it does, but I do not understand how it stops oscillation. 


I have seen 3 in real life.  All are done this way.  One thing I found beneficial is to used sealed Pots.  I prefer old Allen Bradleys, but the made in Mexico Honeywells are nice as well.  PEC are as well.  Simply put, they shield.  Yes, I have seen Alpha pots used, but I have also heard a lot of wrecks sound like distortion boxes too.


Look here and listen to a real one.  The cleaner side with the guitar knob is really nice and is what I try to achieve.  Rolling back enough to stop preamp clipping and rolling in to get it.  Do not pump V1 with a boost unless you have a real compressor, not a stomp box compressor.  Listen to Glen's amp on youtube I linked to.  This is what a Wreck is.  I have one because of the mystic, but I have never used it to play a gig.  I play low gain fenders and Marshall.  But I am more of a clean player.


Not saying it is not a fun amp.   When I am home ALONE playing old Whitesnake through a 1960 Marshall cab sounds great.


Good luck!
https://www.youtube.com/watch?v=Y2_12Ler9B8

[Ed_Chambley]

The Express uses a 300mA power transformer with matching OT for 50 watts.

For master volume in the Express go with the PPIMV also labelled as Lar-Mar from Metro-Forum.


I used to use a dual 250kA pot but switched to dual 250KL pot which in the opinion of many sounds better and was originally suggested by Larry and Mark on their Lar-Mar PPIMV

+1 on the master.  I prefer linear.  I believe MFowlers comments on wattage is not clean output, but PP El34's will do more than 50 watts.  It is common to reference a pair as 50 watts, but crank a Bassman next to a Plexi in the same cab.  Trainwrecks are not really categorized the same as Low Gain wattage.  The expectation is to lower the input to get clean.  Maybe then you will measure 30 to 35 watts.

[Ed_Chambley]

Here is the best docs I have seen on the Express attached.  I had to break it apart to get it to upload. 

[adamG]

Ed,

Thank you very much!
Now, everything is clear.I always listen the words of wisdom...
I can see, what the TW is.

BTW, I heard Glen before. He's a very good meister:)

Best regards,

Adam

[purpletele]

Ed,

Thank you very much!
Now, everything is clear.I always listen the words of wisdom...
I can see, what the TW is.

BTW, I heard Glen before. He's a very good meister:)

Best regards,


I have one or two TW chassis if you are interested.


Adam

[adamG]

I have one or two TW chassis if you are interested.

Thank you very much, but fortunately, I can easily handle that with my hands. Chassis is not a problem for me to make it.

Best regards,

Adam

[MFowler]

By the way if you are an Ampgarage Forum member there are already schematics showing Express with reverb, Rocket with reverb etc. in the Trainwreck Files Section done by 10th also a member on this Forum.


My comment above was regarding mA ratings: 300mA can easily be used to build a 70w amp and I've used 150mA Hammond PT to build 30w amps where 200mA would be better suited for 30 to 50w builds.



Mark