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Going to source all my parts, general guidelines? 
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The guy from the place with the thing. The one with the stuff.
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Post Going to source all my parts, general guidelines?
Made a new thread because it might be useful for other peoples future reference.

Hot Cat 30 clone. Its a high gain build so noise is important but $$$ is very important too.Here is the schematic and the layout I'm going to use(same as the other thread).

Schematic:
http://i266.photobucket.com/albums/ii24 ... cat_30.jpg

Layout:
http://www.ceriatone.com/images/layoutP ... iatone.jpg

Resistors:
1. Thinking of using metal film resistors for the 1/2 watt and 2 watt because of low noise but im not sure what to use for the 10 watt.
2. Shouldn't the plate load resistors be rated for more then the B+ voltage? so probably anything at least 400v?
2. Probably buy these all at mouser. OK/not OK?

Capacitors:
1. General: Brand and types to use and to avoid?
2. Filter Caps: Anything else other then whats above?
3. Coupling caps: Its not specified but shouldn't these have a decent voltage rating? Possibly just in case the plate load resistor fails?
4. Also buy at mouser? I think I read there is somewhere better to buy these.

Everything else:
1. Eyelet vs Torret boards? Seem like two very similar ways of doing the same thing. I think I'm just going to go with whats cheapest. No clue where to get these or parts for these if I decide to make them myself.
2. Pots: Where and what to buy? Any specific wattage ratings I should use?
3. Wire: Gauges and where to buy? Any other place I should use shielded wire not specified in the layout?
4. Chassis: Seems like it might be a little hard to make myself...
5. Misc: Jacks, Imp selector, tube sockets, switches, fuse holders, pilot light anything else I might have forgotten?

Transformers get another thread... :cop:


Sun Oct 24, 2010 3:25 pm
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Winston Wolf
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Post Re: Going to source all my parts, general guidelines?
knope wrote:
Resistors:
1. Thinking of using metal film resistors for the 1/2 watt and 2 watt because of low noise but im not sure what to use for the 10 watt.
2. Shouldn't the plate load resistors be rated for more then the B+ voltage? so probably anything at least 400v?
2. Probably buy these all at mouser. OK/not OK?


1. Metal film is a good choice for the 1/2 watt. Depending on what you find, metal oxide for the 2w is fine, and usually what i wind up with, also. The 10w should be wirewound. Or you might find them on Mouser as "Cement Power Resistors" They are big, chunky square things, and should be about $1 a piece. Make sure you choose carefully, and look at the data sheet for whatever you buy. It is relatively easy to buy gigantic resistors accidentally. Just make sure that the wattage rating is right, and make sure that the resistor isn't listed in the data sheets as being eight inches long or something. :idea:

2. I generally use 1/2w resistors for everything except for the voltage dropping resistors in the power filter section, and the cathode bypass on the power tubes.

3. Mouser is definitely the best bet for these sorts of things.


Quote:
Capacitors:
1. General: Brand and types to use and to avoid?
2. Filter Caps: Anything else other then whats above?
3. Coupling caps: Its not specified but shouldn't these have a decent voltage rating? Possibly just in case the plate load resistor fails?
4. Also buy at mouser? I think I read there is somewhere better to buy these.


1. I hate Sprague electrolytics because they are fucking gigantic and stupidly expensive. I hate Illinois electrolytic caps because they seem to be underrated(meaning they don't stand up to the voltages they are supposed to) and generally shitty.

2. If you can find them, Tech-Cap are great filter caps. They are smaller, and they are high quality with good specs, and not too expensive. Last i checked, Mouser wasn't carrying them. If you want to stick with one vendor for most of your stuff, the Xicon caps are pretty good and dirt cheap. Make sure that if you want axial caps, that you order axial caps. That said, radial lead caps tend to be less money, which would mostly only be useful to you if you knew what you were doing and made your own layout for using them.

3. Coupling caps should all be 630v. Xicon, Mallory, Sprague, IMO, it doesn't really matter, and the pricing is generally relatively close between them, with Xicon generally being the least $$. Again, make sure that you order carefully, as accidentally ordering something that is rated for more than 630v could mean you get a bunch of huge capacitors in the mail. :cop: 630v is what you need. You could even get away with 400v in a lot of map applications, but there is IMO, no reason to. 630v are readily available and not too expensive. Buy more of them than you need!

You can get away with getting all of this stuff from Mouser too. If you want to seek out Tech-Caps, you will probably have to buy them somewhere else. I know of one plae that sells transformers, that also has/had them, so you might try that if you get your transformers there. Otherwise, you might just wish to save on shipping to PR, and get all of your caps resistors and pots from Mouser. They are quick and reasonable with shipping.

Quote:
Everything else:
1. Eyelet vs Torret boards? Seem like two very similar ways of doing the same thing. I think I'm just going to go with whats cheapest. No clue where to get these or parts for these if I decide to make them myself.
2. Pots: Where and what to buy? Any specific wattage ratings I should use?
3. Wire: Gauges and where to buy? Any other place I should use shielded wire not specified in the layout?
4. Chassis: Seems like it might be a little hard to make myself...
5. Misc: Jacks, Imp selector, tube sockets, switches, fuse holders, pilot light anything else I might have forgotten?


1. Eyelets are cheaper. Turretboards are maybe a little easier to work with. Turretboards are also a lot taller, which might be something to note, depending on what you wind up using for a chassis. I usually get mine from this guy: http://www.hoffmanamps.com/ who is awesome, and very fast for shipping.

Some more punk rock types have actually reported some success using the right sized eyelets from a craft store also. If you attempt it, you will have to test whatever eyelets you find beforehand, as some of the chrome plated ones will NOT be compatible with solder. Even if you do find something locally, you will still need to get the board material somewhere. Don't mess around with this, you need to buy proper for-electronics-use, G10-style fiberglass circuit board.

You will also need a way to stake the eyelets in the board. It is simple, and a staking tool is also simple. Hoffman sells them, though with a little ingenuity, you could probably hack something together that work work.

2. For pots, you want to buy at the very least, Alpha 24mm 1/2w ones. They are the cheapest option, Mouser has them usually at something like $1.50-ish a pop. Buy at least twice as many of each value than you need. Because they are cheaper pots, you can fuck them up. They aren't fragile or anything, but they can be destroyed, such as with accidentally dripping hot solder into them, or just generally overheating or being rough with bending the soldering lugs around. It absolutely sucks to destroy the one pot of a certain value that you have, and have to wait for another one to come in the mail before you can make the amp work again. :facepalm:

Also, pay attention to whether you are ordering an Audio/Logarithmic taper pot, or a Linear taper one.

ALSO, pay attention to whether you are ordering knurled or plain shaft pots. Knurled for press-on knobs, plain for knobs with set screws in them. Usually for amp building/DIY stuff, you will want the plain shafts.

ALSO ALSO. Pay attention to whether you are ordering PCB lugs or solder lugs(what you WANT). It is a pain in the ass to work with PCB lugs for building an amp that isn't on a PCB board.

3. You can get wire lots of places. Hoffman sells it. You can also seek out teflon/PFTE wire if you want. It is harder to mess up with the soldering iron(actually practically impossible to mess up with the soldering iron) but it also can be a complete pain in the dick to get the teflon jacketing off with normal wirestrippers without messing something up. Normal wire should be fine, unless you are really terrible with the soldering iron. Generally, for normal stranded wire, you would want 18awg for the heaters, and about 20awg for the rest.

4. and 5. All of this stuff, you can get from somewhere like Hoffman, or for some more options, somewhere like this: http://turretboards.com/ That guy has a lot of stuff(also boards and eyelets, and even if i recall correctly a Hotcat 30 board). His prices are a bit higher, but he does have a lot of stuff you might want. Check it out, but always, compare the prices, and determine for yourself, if it is really going to work out cheaper to get everything from one more expensive place, or from a bunch of less expensive places. Always remember to factor in the shipping when you compare that way. A lot of times i would order pots or something from Hoffman or Turretboards.com, even though they are considerably mroe expensive than Mouser, just because i was already ordering something else, and paying the other shipping charge for mouser would make the total cost between the two almotst the same, or, close enough not to matter to me.

Good luck. Sourcing parts for your first build can be daunting. You might expect to screw it up. The process gets much easier once you get through that first one though. :nods:

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Sun Oct 24, 2010 4:31 pm
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Winston Wolf
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Post Re: Going to source all my parts, general guidelines?
Oh!

1. Electrolytics should be rated for a solid amount more than the B+ you expect. I usually try to get 450v or 500v. But in amps that aren't expected to give above it, i have also used 350v.

2. Cathode bypass electrolytic caps for the preamp should be rated for about 25v.

3. The cathode bypass capacitors for the power tubes should be rated for about 100v.

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Sun Oct 24, 2010 4:39 pm
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Post Re: Going to source all my parts, general guidelines?
Thanks for the info Chris! I pretty clear on about everything but I'm having a hard time finding the 0.0015uf coupling caps (1n5 on the schematic). Not to hard to find the 0.001uf or 0.0022uf though, I'll just probably buy both and see which I like best... This affects the bass response correct?


Sun Oct 24, 2010 10:33 pm
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Winston Wolf
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Post Re: Going to source all my parts, general guidelines?
Hang on i will see if i can find some. Looks like they are out of the 630v ones i normally get.

They might also be listed as 1500pf.

You may end up needing to order a ceramic cap for it.

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Sun Oct 24, 2010 10:39 pm
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Winston Wolf
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Post Re: Going to source all my parts, general guidelines?
You could also use these: http://www.mouser.com/ProductDetail/Xic ... qOhoQjA%3d

They are radial leads, but they would do the trick. The only issue you might run into with them is the two that go on the board. Depending on the turret spacing, you might have to make the lead a little longer on one side to reach. :idk:

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Sun Oct 24, 2010 10:44 pm
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Winston Wolf
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Post Re: Going to source all my parts, general guidelines?
Either of these would work, also:

http://www.mouser.com/ProductDetail/Cor ... Nr0CwVg%3d

http://www.mouser.com/ProductDetail/Vis ... 6JHvcIg%3d

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Sun Oct 24, 2010 10:49 pm
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The guy from the place with the thing. The one with the stuff.
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Post Re: Going to source all my parts, general guidelines?
Crap... I'm lost on:

Switches: I know I need 4 and the impedance selector, but that's about it :facepalm: (Layout)

Tube Rectifier: What are those diodes and that capacitor doing there? (Layout)

Standby Switch: What is that cap doing there? (Layout)

Eyelet/Turretboard: Im going to make my own, but I could use a little help on the dimensions I need.

Chassis: JTM45 blank sounds good? http://turretboards.com/guitar_amplifie ... _blank.htm

other then that I'm almost done!!! :panic:


Mon Oct 25, 2010 11:36 am
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Winston Wolf
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Post Re: Going to source all my parts, general guidelines?
knope wrote:
Crap... I'm lost on:

Switches: I know I need 4 and the impedance selector, but that's about it :facepalm: (Layout)


http://turretboards.com/guitar_amplifier_switches.html

1. For power and standby, get good quality Carling SPST. Turretboards Hoffman, Mouser, all should have them. If Mouser, then make sure that they are solder lugs, and also: 3A@250V/6A@125V, and fits a 1/2" hole.

2. For impedance, that one that turretboards.com carries is the one you want. Hoffman also sells them.

3. For the diode/ss switch and the half power switch, you want a DPDT On-On switch. Something like this should do the trick: http://www.mouser.com/ProductDetail/Mou ... 1wu1dqQ%3d

Quote:
Tube Rectifier: What are those diodes and that capacitor doing there? (Layout)


They are attached to the SS/Tube switch. In tube mode, they aren't connected, but in SS mode they are. Because the diodes provide less resistance than the tube rectifier, essentially the tube is bypassed in this manner, without actually having to physically switch it out of the circuit itself. You can see this on the schematic. After the GZ34 there are four 1N4007 diodes, then the DPDT switch, and then you can see the capacitor and resistor you mention, on the far right of the filter supply.

Quote:
Standby Switch: What is that cap doing there? (Layout)


To be honest, i am not sure, as unless i am being particularly dense at the moment(possible, as i haven't had any coffee yet) that is not even how the schematic shows it. You know, you might even try asking Nik at Ceriatone about that via email. In the past he has been pretty helpful in explaining why he has done stuff like that. :idk:

Quote:
Eyelet/Turretboard: Im going to make my own, but I could use a little help on the dimensions I need.


You could again ask Nik what his Hotcat board dimensions are, and he might be helpful on it. Sometimes people will buy his boards and source their own chassis, so it should be information that he would be willing to give out. I would actually be surprised if he wouldn't. He is a pretty good fellow with stuff like that. Otherwise, you will have to eyeball it, and draw it out "life sized" and see how much space it needs. You should probably do this before you buy a chassis!

Quote:


I would say that one is almost too big. For a first amp build it isn't necessarily a bad thing to have more chassis than you need(much better than having too little space!). But if i was building the map myself, i personally would probably go for the 17.5"x8"x2.5" one they have. I would probably go with the "inward lip" version also, even though that choice also reduces the amount of space you have to work with inside the chassis somewhat.

What you might want to do, is actually draw out the chassis dimensions on some pieces of paper, see the sizes physically in front of you, and then decide what size you would feel most comfortable cramming the Hotcat circuit into. :idk:

Quote:
other then that I'm almost done!!! :panic:


:panic: :panic:

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Mon Oct 25, 2010 12:43 pm
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Post Re: Going to source all my parts, general guidelines?
One last detail!!!!!!!!

How many feet of wire do I need and how many different colors? :facepalm:

Nik said the diodes and caps are to protect the tube rec (the ones directly on the tube socket) :nods:


Tue Oct 26, 2010 11:35 pm
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Winston Wolf
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Post Re: Going to source all my parts, general guidelines?
I think the last time i ordered wire, i got about six colors, only about 10ft each. I have been using the same wire for the last two or three years, for building amps and certain types of pedals, and i am only just now running out of certain colors. :idk:

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Tue Oct 26, 2010 11:48 pm
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Post Re: Going to source all my parts, general guidelines?
Looks like a cool project. Chris covered pretty much everything really.

I'm going to try my luck with some cheapo filter caps as I'm not getting near their working voltage and for bigger guns stuff they'll be in series anyway. If they suck I'll get something better although its a bitch sourcing quality caps in the UK. All the big component suppliers will either ass rape you or they only sell snap ins and I've never been quite too sure how to deal with those and their stubby little legs.


Wed Nov 03, 2010 8:37 am
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Post Re: Going to source all my parts, general guidelines?
Zozobra wrote:
Looks like a cool project. Chris covered pretty much everything really.

I'm going to try my luck with some cheapo filter caps as I'm not getting near their working voltage and for bigger guns stuff they'll be in series anyway. If they suck I'll get something better although its a bitch sourcing quality caps in the UK. All the big component suppliers will either ass rape you or they only sell snap ins and I've never been quite too sure how to deal with those and their stubby little legs.


Chris is pretty amazing at helping everyone out! The chassis and turret boards should be here tomorrow or Friday... :panic:

I do need some info on transformers though.

PT
1. How close does the high voltage secondary rating need to be to what the schematics say?
2. How much current would I need in each secondary? Not totally lost on this one. If i did my research and my math correctly I need the 5V to be ~2A for the tube and the 6.3V to be 5A for the filaments. Totally lost on the high voltage secondary.

FWIW the PT Ceriatone uses is the same as their 50W Marshall


OT
1. How do I calculate the impedance I need for the primary?


Wed Nov 03, 2010 2:57 pm
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Henry Kissinger
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Post Re: Going to source all my parts, general guidelines?
Bare in mind that rectification will increase the secondary HT voltage by 1.2 to 1.4 times depending on load.

The power supply section here will sort you right out in terms of your questions:
http://www.freewebs.com/valvewizard/index.html

If you're stuck then we can go through it with you.

For the OT any generic 50W marshall type will probably do if thats what ceriatone use. You're using 2 EL34s so a primary of 3k25 is about right. I guess the reason its 30W is because it cathode biased?


Wed Nov 03, 2010 5:11 pm
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Winston Wolf
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Post Re: Going to source all my parts, general guidelines?
For the Hotcat, IMO, you will want more like Vox transformers than like Marshall ones.

The reason it is only rated for 30w, is due to the B+ voltage, in conjunction with the biasing, AND the output impedance.

Read here for the proper detailed info: http://tdsl.duncanamps.com/show.php?des=el34

You can see that a B+ of 375v(equates to a PT primary of roughly 267v-270v with an SS or GZ34 rectifier) into an output impedance of 3.4k, with a cathode bypass resistor of 130Ω, will be expected to give about 35w in the datasheet here:

Image

So as in that example,in the case of the Hotcat, i believe that the B+ is much closer to the range that they would use for their EL84 amps than the almost 500v that a Marshall EL34 circuit would spec out. In fact, it may even have the same power transformers as Badcat's other 30w (EL84) amps. For instance, the similar Matchless amps shared power and output transformers across much of, if not the entire, range.

If i were to build a copy of the Hotcat, i would probably go with Trainwreck style transformers, which are similar in some aspects of their design theory to what Matchless/Badcat do, i.e. lower B+, and then a "mismatched" output impedance specification from what is generally typical in Fender and Marshall maps.

For the PT, this would be usually about 270-0-270 to 280-0-280 @ 250mA to 400mA, depending on what you want to spend and what you expect to make it do. Anywhere from 4A to 7A on the 6.3v. And about 3A on the 5v if you are going to use the tube rectifier.

For the output transformer, it would be something which is a higher output impedance than a "typical" EL34 circuit, at either 5.2k-ish or 6.6k-ish impedance, rated for 35w or 40w. The Trainwreck Express for example uses 6.6k for its EL34s, for a pretty sizable mismatch from what is 'normal'.

I would probably get them from this guy: http://www.rjguitars.net/Transformers.html as he has a few different options, and he also sells Tech-Caps. He has a note on the mainpage about orders maybe taking a bit longer this summer, but i would probably try him anyhow. (If i was building the amp!)

Otherwise, those specs are what you want.

PT.
HT: 270-0-270, 275-0-275, OR 280-0-280 @ about 300-400mA
6.3v @ about 5-7A
5v @ 3A

OT.
35-40w rated, push-pull.
Output impedance of anywhere from 3.2kΩ to 6.6kΩ

:idk:

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Wed Nov 03, 2010 6:36 pm
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Post Re: Going to source all my parts, general guidelines?
Oh, and FWIW, i don't know for sure what the Hotcat OT uses for output impedance. But i am merely speculating, keeping in mind how they have done their other amp designs.

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Wed Nov 03, 2010 10:07 pm
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Post Re: Going to source all my parts, general guidelines?
Both you guys are great! :love: :love: :dastardly: :panic: :eyebrows: :rawk: :fag: :dildo: :dance: :D

SO...

PT
1. From http://www.rjguitars.net/Transformers.html
a. EM 0748 (what would I do with the 50v tap? ground it?)
b. HTS 9144 (6.3V @ 7.5A too high?)
2. http://www.mojotone.com/amp-parts/Power ... ransformer

yes/no/maybe?


OT- you are making it tough. What are the audio differences between different imp? Say, would it be tighter with 3.2k ohms vs 6.6k ohms?

Choke- forgot about this... anything between 30H and 40H should do right? Schematic says 36H, but I haven't seen any that aren't either 30 or 40...


Wed Nov 03, 2010 11:09 pm
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Winston Wolf
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Post Re: Going to source all my parts, general guidelines?
Oh cool, Mojo is posting .pdfs of their transformer specs now. IIRC, they didn't used to.

Any of those power transformers would be fine. The 50v tap, you most likely would just wind up shrink wrapping(to keep it isolated from touching anything) and tucking away into a corner of the chassis.

For the OT, it is difficult to say. The mismatching tends to make the amp seem more compressed. It is a key component of the Matchless/Badcat, and the Trainwreck's somewhat unique sounds. It also affects the way the amp feels, and you might hear it as more harmonics and compression. You might feel it as more responsive. It may have a fair bit to do with why the amps that utilize the mismatch have certain characteristics that are similar, such as their controllable feedback, and the manner in which leads sustain, etc... It would come at the expense of some volume though, as a mismatch is an inefficient way for the amp to operate.

Also worth noting, due to the mismatching, these "30w" transformers are the same size as most other types of "50w" transformers. The mismatching is stressful on the components, so they need to be and are extra beefy. A mismatch may also take its toll on your power tubes to some degree.

3.2k or 3.4k is a pretty common value for an EL34 amp, and is right in line with the tube data sheets for a lower voltage push-pull cathode bias amp.

The Badcat is probably a mismatched OT though. Your choices would then basically be to either:

1. Find out what the Badcat OT is. As far as i am aware, this information is not available out there. The TDS part number listed on the schematic, is as far as i am aware, a proprietary unit, and as such, TDS will not disclose the specs of the transformer.

2. Just go with 3.2k/3.4k and possibly wind up with a louder, harsher, or less unique sounding amp.

3. Take a guess at the mismatch and have something custom built. (Or learn the science behind choosing output impedance with a mind to controlling the frequency bandwidth with the OT acting as a sort of filter to accentuate certain desirable frequencies or attenuate less desirable ones. Good luck. :lol: )

4. Use a nice mismatch value that sounds good in another low volume, high gain EL34 circuit(the Trainwreck Express) and go with 6.6kΩ.

:idk:

For the choke, just about anything 20-36H @60-75mA will be fine. An AC30 or DC30 choke would be fine.

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Wed Nov 03, 2010 11:39 pm
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Winston Wolf
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Post Re: Going to source all my parts, general guidelines?
Oh, and 7.5A on the 6.3v would not be too much. You probably won't need quite that much, but if you can afford the transformer, and it isn't considerably larger physically than the others, it will be fine, even desirable. Having enough amperage there will mean a good steady supply to the preamp tubes, and can help avoid overly saggy reaction/dynamics and whatnot in a high gainer. :idk:

Also that multitap Heyboer looks like a pretty sweet transformer. Probably more than you need for what you want, as i don't think you are likely to want to experiment with the 250v taps, but even still, nice.

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Wed Nov 03, 2010 11:56 pm
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Post Re: Going to source all my parts, general guidelines?
Hmm... I think I'll actually go with the edcor 35w OT at the top of the rjguitar page. Dual primaries :nods:

PT- Probably whatever fits inside the chassis :lol:


Sat Nov 06, 2010 9:05 pm
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