Component brands

[benoit]

I'm building a rocket off the schem done by matt taylor, and am working on my BOM. I've looked around the forum quite a bit, and all I've found so far is that Mallory PVCs or OD 6PS is the way to go for signal caps. Is any old brand ok for the rest of the caps? Obviously coupling and tonestack type caps are PVCs. What about the cathode bypass caps? PS filters? And what of resistors? I don't want to be spending 3 bucks a resistor but I want to use good quality stuff.

Ben

[paulruby]

If you want to do an EXACT clone, ignore what I'm about to say...

It's not that important... Get everything else from Mouser...

Use metal film, 1W resistors for most all (except where higher wattage is needed).

Just use xicon electrolytics and you'll be fine. If you want to pay a bit extra for sprague/vishay, feel free.

I use JJ can caps to minimize the internal chassis space used. If you're using a full sized wreck chassis, then just get axial xicon caps.

If you intend to solder to the backs of your pots, just get the cheap alpha and sand the pot backs to solder. I like clarostat RV4 pots myself but you can't solder to the back.

Don't use the really cheap switches from mouser. I would suggest getting clarostat switches.

If you decide to go with the good pots and switches, get them from Dave at West Labs online. He orders in volume from digikey and then sells for a lower price that you can get for low volume from digikey. And it really is good stuff. The mechanical components need to be high quality to feel good and last long.

[benoit]

Thanks Paul.

An exact clone may be in my future but for now I want to build something that will sound nice.

A few more questions if I may:

1. Xicon for the electrolytics: just the power supply ones or all of them?

2. What kind for the non-polarized caps?

3. If I go with the quality pots, where do I run my ground bus? Do you have build pics?

4. How do I go about figuring out where I need what ratings for components (wattage for resistors, volts for caps)? I would settle for exact values but I'd rather have an explaination of how to do it.

[riscado]

if you go with the clarostat pots, you can always run the grounds to a buss, but instead of attaching them to the back of the potsyou can run the buss isolated from the chassis... suspend it on the board using two turrets or something like that.

[paulruby]

Thanks Paul.

An exact clone may be in my future but for now I want to build something that will sound nice.

A few more questions if I may:

1. Xicon for the electrolytics: just the power supply ones or all of them?

2. What kind for the non-polarized caps?

3. If I go with the quality pots, where do I run my ground bus? Do you have build pics?

4. How do I go about figuring out where I need what ratings for components (wattage for resistors, volts for caps)? I would settle for exact values but I'd rather have an explaination of how to do it.

Get 50V xicon caps for any the cathode bypass caps.

Use 450V xicon caps for any B+ filter caps.

Use 600V caps for all the signal coupling caps. I use mallory 150. Could also use Cornel Dubilier. Just be sure to get caps with polyester dielectric. Mustard caps... Zoso caps... There are lots of options.

Use mica caps for the 500pf and lower values.

Any resistor whose wattage is not called out on a schematic is 1W. All the resistors in the B+ chain should be 2W except the giant 25W 1K.

The power tube cathode resistor for a liverpool or rocket should be 5W.

Pics of a rocket...
http://paulrubyamplification.com/MiriamGuts.jpg
http://paulrubyamplification.com/MiriamGuts2.jpg
http://paulrubyamplification.com/MiriamGuts3.jpg
http://paulrubyamplification.com/MiriamGuts4.jpg

[nickt]

Hey Paul - I notice you're not twisting your preamp heater wires. Is this an experiment or have you found it makes no difference?

BTW the build is just beautiful

[paulruby]

Hey Paul - I notice you're not twisting your preamp heater wires. Is this an experiment or have you found it makes no difference?

BTW the build is just beautiful

Doesn't matter in my layout because all the signal lines fly in perpendicular to the filament lines from above. The filament lines sit down tight against the chassis running "left-right" and the signal lines are up in the air running "north-south".

In general, folks worry way to much about twisting filament lines. I see it more as a hedge against an otherwise questionable layout. Point-to-point layouts, in particular, tend to have signal paths all over the map and twisting filaments is a good idea.

For newbies, I suggest to just twist them since it's cheap insurance.

[benoit]

More questions:

1. Why mica on the lower values? (Silver mica?)

2. Better place to get the 150s than AES (tubesandmore.com)?

3. Good place to get the mica stuff?

4. Is it ok to have lower voltage (500v) ratings on the mica caps or do they need the 630v rating?

5. I found the values I needed, including smaller caps, in mallory 150s. Are the micas just cheaper?

6. What are the various tranny choices available, and what are the pros and cons? Specifically am I sacrificing tone if I go with the toneslut trannys even though the OT doesn't have the 4.2k tap?

[paulruby]

More questions:

1. Why mica on the lower values? (Silver mica?)

yep

2. Better place to get the 150s than AES (tubesandmore.com)?

AES is fine. Mouser also carries them but likely to be back ordered and need to buy lots to get them cheap.

3. Good place to get the mica stuff?

Mouser

4. Is it ok to have lower voltage (500v) ratings on the mica caps or do they need the 630v rating?

500V is OK but don't go any lower.

5. I found the values I needed, including smaller caps, in mallory 150s. Are the micas just cheaper?

Once down to 500pf and lower, the silver mica are physically easier to work with and sound fine. Feel free to mess with outer types if you like.

6. What are the various tranny choices available, and what are the pros and cons? Specifically am I sacrificing tone if I go with the toneslut trannys even though the OT doesn't have the 4.2k tap?

The toneslut trannies are great and are the best that I know of. They are the official heyboer wreck iron and are the only thing I use. 4.2k versus 5.2k is not something to be worried about.

[benoit]

Thanks paul, you've been really fantastic. Now, I forgot to add this to my post last night, but what resistors do you like where? That is, is there a certain type (carbon film, cc, etc) that works better or is cheaper?

Are there any locations where the type of resistor used (brand/construction) is critical to good tone?