5E9 Tweed Tremolux Build Thread: Pics on Page 11

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5E9 Tweed Tremolux Build Thread: Pics on Page 11

Post by wproffitt » Mon Jun 12, 2017 4:20 pm

Hello all,
I've been doing quite a lot of reading and hand-wringing and, last week, I decided to get going with ordering parts for a Tweed Tremolux build. I've ordered the speaker, chassis, and cabinet. Look what else showed up today!
Image
Last edited by wproffitt on Sun Oct 29, 2017 12:57 pm, edited 7 times in total.

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Re: 5E9 Tweed Tremolux Build Thread: I'm Doing This!

Post by Ursa Minor » Mon Jun 12, 2017 5:29 pm

Oh Yeah!

Subscribed. 8)
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Re: 5E9 Tweed Tremolux Build Thread: I'm Doing This!

Post by jimboyogi » Mon Jun 12, 2017 5:41 pm

Very cool! Glad you decided to go for it.

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Re: 5E9 Tweed Tremolux Build Thread: I'm Doing This!

Post by antisymmetric » Mon Jun 12, 2017 7:24 pm

A bit out of my league, but something I'd really like to learn to do. Will be following this...
Watching the corners turn corners

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Re: 5E9 Tweed Tremolux Build Thread: I'm Doing This!

Post by sookwinder » Tue Jun 13, 2017 5:39 am

Great to hear ....
OK.... how are you sourcing your components? via a kit or sourcing them yourself ?

I have always sourced the componenst myself... these types of amps do not have anything exotic as far as components, so sourcing yourself is dead easy.

I am sure I (and others) will give you many helpful hints as you go down this path.
Here's first .... When I first started building amps I wanted a genuine build that reproduced the Fender amp exactly and using the exact some components.
There are a number of problems with this notion:
1. The original design's by Leo were done when valve amps were in the infancy and many "safety" designs or sections of designs that are commonplace now he did not implement.

2. The designs were done to ensure a cheap mass produced product .
Your amp is your personal build and for the sake of less than $10 extra spent on components you can dramatically improve the build without deviating away from the original design very much

3. You cannot buy the original "tone" capacitors because this isn't 1958. Boutique capacitors while they do sound good (in my experience) would not be even noticeable in this build. Leo used stock standard (even WWII surplus) components. There are many good quality cheap (or not that expensive) caps out there. Off the top of my head... Mallory M150s would work perfectly in this build for the tone and coupling caps.

4. I used original 1960s NOS Allen Bradley carbon comp resistors in the first few amp builds... because that is what Leo used.
Problem is that over the past 50 years many of those resistors have drifted and they are no longer even within 10% of their nominal value.
Also CC resistors are noisy... old one, 50 year old CC res arte very noisy.
Me ? I now use brand new Metal Film resistors ... the two watt metal film res look like and are the same size as the old 0.5watt CC res. Win/Win

5. Leo's designs generally use they chassis as the earth/ground connection. For example the ground on the pots are usually soldered to their own back faces... this means that they are earthed through the connection to the chassis. This is OK ... but sometimes earth loops or hum can occur... I do not think your amp will have that issue as it is a design that doesn't have a complicated layout. (I prefer to use a combo of star/ earth rail... but that is where I have reached on this path of amp enlightenment !)
You can make your life and your amp have a betyer chance of having a good earth/ground set up, but grinding (with a dremel or sand paper) the galvanising around the inside of the chassis whether the pots will be mounted to ensure a clean connection between the pots and the chassis metal.

6. If you have a choice of the $2.50 pilot lamp holder or the $3.50 one... choose the $3.50 .. no brainer

7. Lastly I would add 4 resistors to Leo's design. These are standard design attributes that any amp made these days would have, as they save the power valves from dying if there is a surge or something else commits suicide (red res -= screen res) and stops blocking distortion (Blue res)
The values for these screen and grid res vary quite widely ... what I have shown below is what I have used and what I have seen many others use.
If you check out similar modern amps or even maybe SF amps that are 2 x 6V6GT you will see these resistors.

You can hang them off the valve socket lugs if you wish

as always .. ask questions and we all will be happy to help ... just as people here helped me years ago.

Image

Notice one extra red wire and I have removed a wired that connects pin4 on each 6V6GT
Image
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Re: 5E9 Tweed Tremolux Build Thread: I'm Doing This!

Post by wproffitt » Tue Jun 13, 2017 5:38 pm

sookwinder wrote:Great to hear ....
OK.... how are you sourcing your components? via a kit or sourcing them yourself ?
Thanks! I'm sourcing much of this for myself:
1) cab--Mather
2) board-- Watts Tube Audio
3) 5E9 Chassis--This doesn't actually exist, so I've purchased a 5E3x2 chassis from Weber (it is 17.5" long like the originals) and am putting a couple of extra holes in it for the Depth and Speed controls. Thank God I have access to a drill press!
4) Speaker- Weber 12a125A (30 watt).
5) Transformers- I'm probably going Heyboer or Mojotone (which are made by Heyboer, I think)Tweed Deluxe style transformers for this.
6) Caps, resistors, fuse, switches, jacks, wire, etc.- The smaller parts are something I'll probably leave up to Dave Whalen at Boot Hill amps. He does partial kits (mainly Deluxes and Champs) but is putting together a 5E9 "kit" of small parts for me. He uses what looks like good stuff (like Mallory caps), but doesn't seem too slavish to Leo's original spec:
http://boothillamps.com/5E3_Kits.html
7) Thoughts on tubes, anyone? I've been flirting with the idea of modern production for a couple of spots in the circuit (the second 12AX7 preamp tube and maybe the 6v6 power tubes), but NOS for the the 12AY7, the first 12AX7, and 5Y3 rectifier tube. Are there places where it matters more than others?

-As to your thoughts on grounding, I've been reading through your thread on the Nightverb Reverb for ideas on grounding schemes. I'm definitely not going with the brass bar that would have been used in the original!
-Thanks for the tip on the placement of the four additional resistors in the circuit. Double-thanks for drawing them into the wiring diagram as well as the schematic so that I can read them!
-I will be asking for advice (questions like, "How does this board look before I solder it all up?") soon enough. I thank you and the others in advance for your patience with me.

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Re: 5E9 Tweed Tremolux Build Thread: I'm Doing This!

Post by sookwinder » Wed Jun 14, 2017 12:56 am

this build of mine also allows you to see how I earthed this amp
http://www.offsetguitars.com/forums/vie ... 10&t=76990

you don't have to use the brass rod, but keeping the earths of different sections isolated from each other until they hit a single node I have found to be a good way to reduce hum. So the preamp earths will all be together up one end.
The trem earths can be together and come to a common point down near the PT
Likewise the phase inverter/Power section earths also should come down to their own point and then onto the common ground near the PT.

On the schematic, I like to colour the various ground points of sections unique colours so I get a sense of what goes together and what should be separated
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Re: 5E9 Tweed Tremolux Build Thread: I'm Doing This!

Post by jimboyogi » Wed Jun 14, 2017 2:02 am

Great advice coming from Sookwinder, who's designed and built quite a few amps now :)

Here's a bit (lot!) more information on grounding schemes, from a super helpful website.
http://www.valvewizard.co.uk/Grounding.html" onclick="window.open(this.href);return false;

If you haven't already had a look around this site, then delve in! I also heartily recommend the pre-amp book. Essential to my education in all things valve/tube.

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Re: 5E9 Tweed Tremolux Build Thread: I'm Doing This!

Post by wproffitt » Wed Jun 14, 2017 6:21 pm

David,
Thanks for pointing me to the thread on the Vibro Groove. Somehow, I missed this one! So, if I'm reading the pictures correctly, you're going from the bus bars to points at either end of the chassis. It looks like (just as on the Nightbird) you're bolting those grounds to the chassis rather than soldering. This seems much more sensible than trying to solder to the chassis. Am I reading this correctly?

James,
Thanks! Fellow forumite Racing beat you too it with recommending the Valve Wizard site. I'm most of the way through that essay on grounding schemes now! There's some really good information here and it's not so technical that a Latin teacher like me can't understand it. :)

I ordered my PT and OT from Mojotone today. After that, it'll be time to order the tubes. For this build, does anyone have any strong opinions on NOS versus new production? I'm not going cheap on this build, but also don't feel compelled to pay the extra money for an NOS 12AX7 that's going in the socket for the trem if there's no tonal benefit to that. I'm open to all opinions on this.

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Re: 5E9 Tweed Tremolux Build Thread: I'm Doing This!

Post by sookwinder » Thu Jun 15, 2017 2:36 am

Yes I bolted the earths to the chassis, with star washers between each spade connector.
Why? Gives better grounding

But more importantly from a build perspective, you can undo (unscrew) the earth connection and change things around if you wish to. Or isolate sections when trouble shooting.

If you read Merlin's site/books you will see this , but in short each section of your amp is run off different DC note points.
The PT is run of the node that is closest to the DC voltage coming from the rectifier. This is usually the highest valued node.
This DC voltage node has "average" level of filtering ie. there still maybe a ripple in the DC from the AC wall power.
But because this is powering the PT, which combines two half signals (after the Phase inverter) the ripple is usually cancelled out.

the next DC node powers say the power valves ... again slightly less ripple and less voltage level because the DC power voltage has gone through a res/cap filter and the overall DC has dropped a little.

the next DC node powers the trem and the phase inverter as well maybe... even say the 3rd gain statge (half a 12AX7 or 12AY7)

The next DC node has even less voltage but it also has far less ripple.
This may be the final node and powers the input preamp section... you need basically perfect DC hear as any ripple in the DC signal will then be amplified back through the amp.

It is worth spending an hour looking at various amp schematics from this site http://www.thevintagesound.com/ffg/ and you can see the input voltage from the rectifier and then see how the various DC node points drop down the DC voltage level.

In some amps like the VC or DR or TR were you are trying to get as much power as possible out of a design, the DC nodes can have quite high values even for the preamp. But in the case of the BFPR, the dropping resistors between nodes are large and cause the voltage at the final preamp section node to be relatively low ... as Leo wanted to create a very clean low/med powered amp.

I have just designed/built a preamp unit for my Rhodes that allows me to plug it directly into a recording desk at line levels but still have the valve amp texture/sound and valve OD (one can also plug a gtr in as well. (I am yet to write this up as a thread... but will do so in the next month or so) It took me about a week to determine the best combination of dropping resistors to get the levels of DC at the different nodes that was optimum for the design. Thankfully for you, Leo has already done that.

Now.... the thing that took me some months (years ago) to discover was that the earth/ground for the preamp section is best to be located away from the other earths, but near the input jacks ... a short distances away.

The actual input jacks use the chassis as ground (ie they are not isolated ... although some people do use isolated input jack, once I worked out what was best for my style of amp design I have never needed isolated input jacks). So the ground for the preamp section node (the last node) needs to be close to the other earths in the preamp section circuit.... so you can see in my circuit for the Vibrogroove I have those few grounds from the valve cathodes and the tone controls all going back to that bolt earth near the input jacks. The earth from the final preamp node also goes back to that earth near the input.

Also the lead from the input to the first half of the 12AY7 needs to be shielded cable and then you connect ONLY ONE END of the shield to the chassis as well
The lead from the volume to the second half of the 12AY7 also needs to be shielded.

The remaining nodes can have their earth/ground points on the other side of the chassis near where the PT and all the high voltage stuff is grounded....

have I lost you ?
questions?
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Re: 5E9 Tweed Tremolux Build Thread: I'm Doing This!

Post by sookwinder » Thu Jun 15, 2017 2:38 am

Oh one more thing.
If your wallet can afford it ... always go vintage.... NOS is good, but then slightly used (taken out of 60s/70s/80s nuclear bunkers) is also perfect.
Definitely get a NOS 5Y3GT ... it will outlive you !
There are plenty of deal on ebay for NOS or slightly NOS valves (if that makes sense)
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Re: 5E9 Tweed Tremolux Build Thread: I'm Doing This!

Post by wproffitt » Fri Jun 16, 2017 4:14 am

David,
Going over the schematics is quite a bit more helpful in understanding what you're saying about the nodes than looking at the wiring diagrams! It'll probably be a few more weeks before the rubber meets the road with this and then I'll have many questions about shielded wire vs regular cloth pushback stuff. As for the tubes, I've decided to go at least mostly NOS. looking at the cost breakdown in a spreadsheet has convinced me that, in the big scheme of things, it's really not THAT much more money, especially if hey are likely to last longer and sound better.
-Stay tuned, folks! A delivery from Weber should be arriving today. ;)

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Re: 5E9 Tweed Tremolux Build Thread: I'm Doing This!

Post by wproffitt » Fri Jun 16, 2017 2:37 pm

Look what showed up in the mail today!
Image

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Re: 5E9 Tweed Tremolux Build Thread: I'm Doing This!

Post by ziess » Fri Jun 16, 2017 11:12 pm

Chassis looks great. Did you punch he extra holes and label it yourself?

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Re: 5E9 Tweed Tremolux Build Thread: I'm Doing This!

Post by wproffitt » Sat Jun 17, 2017 5:29 am

Thanks! When I called Weber to order the chassis and speaker, they farmed out the creation of a faceplate to a local graphic design firm. I still have to drill the speed and depth holes in the chassis myself. Thankfully, I have access to a couple of drill presses.

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