[_Knighthawk_]

Hey everyone,

I am just sourcing all of the parts for a scratch 5E8A build. As always, I am very interested in people's opinions on various things and also as always, I will be posting updates and pics throughout the build. Here are the basics that I am moving on atm:

MM trannies, Weber chassis/boards and brass plate, CTS pots (1 MEG pots are pricey), switchcraft jacks. Still working on tubes (I have sourced some vintage - NOS - GE tubes for the preamp and will be trying to find some NOS tubes for the power section) and speakers....which takes me to my first question in this thread:

I wanted to open with a question about speakers. What speakers would you recommend for the Fender Twin? I am aware that the Fender re-issues use Eminence 'Special Design' Weber alnicos. I have also read that EC had his Twin outfitted with a couple of vintage Jensen Gold labels. Other sources recommend Weber 12A150A.

Your considered opinions would me most graciously appreciated.

Cheers to all.

 

[tonenut]

If you like clean and sparkly, check out the Weber California with aluminum dust caps. Any particular sound you are after?

 

[_Knighthawk_]

Aluminum dust caps? Interesting...

Tonally, I'd like to go after something like what Clapton was getting from his Twin (post-mods).

Please don't misunderstand - I am not Eric Clapton - nor do I think I am Eric Clapton - just love the tone he got out of his Twin.

I am using stratocasters and Les Pauls.

 

[tonenut]

Here are a couple of Youtube videos with the Cali. The aluminum dust cap can be a bit harsh sounding for some people, others like the bite and clarity. Eric's amp sounds bright, but not that bright.

The British voiced speakers from Weber are probably a bit closer to Eric's sound, like the Weber Blue Dog or the Thames, as they are pretty bright but not overly so.

A combination of a Weber Blue Dog and a Silver Bell sounds excellent too. The Blue Dog is bright and the silver bell has a bit more bass, so the combination balances out nice.

 

[_Knighthawk_]

Very cool, man. Thanks!

I do like the blue dog/silver bell combo. Would never have come up with that one on my own. That said, I have no idea what buddy meant when he described it as 'woody'.

The California in the ToneKing sounds pretty awesome too. Not sure how that would translate to the Twin.

 

[_Knighthawk_]

Hey,

So, I found a box of old (NOS) GE and CGE 12AT7s and wondered:

1) Is there any point to having matching 12AT7s in the Fender Twin (5E8a) build?
2) Are these old GE tubes worth using? I have no idea what kind of quality they are - though I do know they have never been used.

Anyone have any wisdom they can share on this subject?

 

[Lincoln]

A little less gain, so overall a cleaner tone?

 

[tonenut]

You can find tube sound comparison videos on Youtube. From what I remember the GE's sound pretty good, a bit richer sound than some of them. I've personally been partial to slightly unmatched tubes on the power side of the amp, they are a bit grittier that way. Not sure what matching preamp tubes sound like, as I've never had an amp with more than one tube in the clean preamp stage.

 

[_Knighthawk_]

You can find tube sound comparison videos on Youtube. From what I remember the GE's sound pretty good, a bit richer sound than some of them. I've personally been partial to slightly unmatched tubes on the power side of the amp, they are a bit grittier that way. Not sure what matching preamp tubes sound like, as I've never had an amp with more than one tube in the clean preamp stage.

I watched a few videos - using a few different amplifiers (Marshall, Orange [MicroTerror], Peavey 5150) and I was actually aurprised by the difference across different types of preamp tubes (used in V1). That said, I think it will come down to personal preferences...which means that I need to start testing on my own amplifiers (Marshall 18s, VibroVerb, 5E3, Brown Sugar and the soon to be built 5E8a). Thanks for the pointer - it has helped me to understand the variances (and the need to pick a tube that suits my personal preference/sound).

 

[jb welder]

Circuits are designed for a particular tube type. So when you put in a tube that is a close variant, but not the one the circuit was designed for, you are hearing a tube not working to it's optimum parameters. If the stage was redesigned (bias point etc.) for the tube you put in, the difference may not be so noticeable. So it's not just the tube type making the sound difference, but how it is interacting with the circuit. Mostly I'm talking preamp tubes here.

Not that it really matters, just thought I would point it out. Agree that it comes down to what you like and you should let your own ears be the judge.

 

[_Knighthawk_]

Thank jb welder. A point well understood.

The videos I watched all focused on swapping out various brands of preamp tubes (12AT7s, I believe).

I have included a picture of the box of tubes that I found laying around. Gonna have to try them out.

 

[_Knighthawk_]

Started wiring up the board. I am not an expert with the soldering iron but there are no cold solders. I also check every component to make sure it is +/- 2%.

You may notice some variance in parts - I am using up what I had laying around.
(I'm not cheap, I am frugal and this build is for me anyway so why the hell not?).

More to follow...

 

[tonenut]

Lookin mighty fine! Keep us posted, and please provide a link to a sound clip when done!

 

[_Knighthawk_]

Board is done and I picked up the cab from Derek yesterday.

Have yet to order the trannys and still fretting over speakers (pun intended).

 

[_Knighthawk_]

So I am torn about which PT to purchase for this build. I have my Mercury Magnetics PT/OT all picked out but then I thought maybe I could save a few bucks by purchasing a Hammond PT from NextGen. That's where the fun began - I couldnt figure out extactly which Hammond PT to purchase. They do list their PTs by amp model but of course their is no 5E8A listed on their site. After a great deal of research, the closest I can find is the 290EZ (330-0-330, [email protected], [email protected]).

The Mercury magentics spec for the 5E8A is the FTLPT - which is a bit different - 6.V @ 6A.

Does this idfference matter? Should I just break down and spend the extra bucks for the MM PT? Does it matter to the OT?

Sorry for my obvious ignorance with this question.

 

[oldjoat]

doesn't matter to the OT ... just the tubes (heaters ) ... add up the heater draw and make sure you cover it by a bit.
too many amps delivered = no big deal
too little and the PT will overheat , cook off and you've wasted money.

OT is dependent on the output tubes (and configuration SE , push pull) and the speaker load in ohms.

 

[Lincoln]

That 5V winding is for the rectifier tube......or in your case, "tubes". The layout drawing shows two of 5U4G rectifier tubes. The heaters on these tubes require 3 amps of current - each. That makes 6 amp of current required on the 5 volt winding. The 290EZ is only showing 4A on the 5V winding.
Switching to a more modern rectifier tube like the GZ34 for example would solve the problem. The GZ34 only requires 1.9 amps of current. 3.8 amps required for two tubes, just slightly under your 4A available on the 290EZ.

I can't see that change having any affect on tone, but I'm no tech.

 

[RBlakeney]

That 5V winding is for the rectifier tube......or in your case, "tubes". The layout drawing shows two of 5U4G rectifier tubes. The heaters on these tubes require 3 amps of current - each. That makes 6 amp of current required on the 5 volt winding. The 290EZ is only showing 4A on the 5V winding.
Switching to a more modern rectifier tube like the GZ34 for example would solve the problem. The GZ34 only requires 1.9 amps of current. 3.8 amps required for two tubes, just slightly under your 4A available on the 290EZ.

I can't see that change having any affect on tone, but I'm no tech.

It sure sounds like you are.

 

[oldjoat]

Switching to a more modern rectifier tube like the GZ34 for example would solve the problem

so would going with a solid state rectifier ... but you'd lose the "sag" under load.

 

[Lincoln]

so would going with a solid state rectifier ... but you'd lose the "sag" under load.

true. But how much "sag" could there have been anyway with two rectifier tubes supplying double the potential current to a pair of 6L6's? The low power twin must have been a very clean machine.
I'm interested, I may have to try building one of these bad boys. Presence control, no tremolo, I'm in!