1st Post (here) : ) My first project: Boozhound Amp

[bottom_feeder]

Coming out of my *LURKING* hole for good I think : )

Diving into my first *from scratch* build" the Boozhound Triode strapped 6V6 Amp. Should be fun - For now, I'm using an RCA Console for the Iron, all the little bits (vishay, Sprauge & Solen Caps, etc.) are coming from Tube Depot & Mouser. For tubes, I have a pretty wide selection of 6sn7's & 6V6's - mostly old(nos) Military tubes.

Not sure of an enclosure yet, but I'm leaning towards seperate power supply and output chassis to maintain scalability going forward - should make it easy to modify one or the other pretty easily.

Are there any hurdles I should be aware of as a first time builder (besides the obvious - HV, ground issues) ? I'll be starting a blog to document the build (and my other projects) to help others going down this road.

thanks for all the knowledge you guys have supplied me over the last year as I built up to this point.

Mark

[SY]

Welcome to the world of sunlight.

You seem to have got it- grounding, lead dress, HV safety, and soldering quality are 99.9% of getting past that first project.

[EvilGenius]

Good luck! I was considering the same project. In fact, I have a printout of the project right in front of me!

Keep us informed! I'm still debating this project or the K-12M as a first step.

[Kent Smith]

Can't go wrong with those tubes! You should love the result. Good Luck!

[1108]

I built this amp a while ago. You should be very pleased with it.

[ray_moth]

Avoid the dreaded hum, the enemy of most of us at one time or another.

Ensure all AC-bearing wire pairs are twisted, especially the heater leads, which cannot be kept away from the vicinity of signal-bearing leads and components.

Shield any long signal-bearing leads.

Use a 'multi-point' grounding scheme and never use the chassis to carry gound currents. Connect ground to chassis at one point only, preferably at the input jack.

I'm not familiar with the Boozhound but another good way of avoiding hum is not to ground the heater circuit directly but to create a centre-tap for the heater supply, with a couple of 100 ohm resistors (or use the physical centre-tap of the 6.3v winding if there is one), and connect that centre-tap to a potential divider between B+ and ground, so that it sits at about +20v; also, connect the centre-tap to ground via a 10uF capacitor.

[jaymanaa]

The old Boozehound. What a great site. JSN has a way of putting things that even I can understand. I started to build that amp for my first and got side-tracked on a SET EL-34 circuit. Are you planning on building it exactley as shown, or tweeking? I've got it printed out somewhere. I'll dig it out and follow along. Good luck and welcome to the fold. Jay

[bottom_feeder]

I'm pretty much following it step by step (less chance of f-up). The only thing up in the air is the chassis / case. Probably just oiled Birch plywood, or maybe really but the console to use and strip it like a buffalo - recycle a piece of door, or side panel, cut it down to use as a chassis . . .

Ray: I like how the old industrial tube stuff had a 16 or 14 guage solid gore ground - thingy from one end of the chaasis to the other. I parted out an old variable power supply for caps / variac / etc and still have the tank of a chassis. Icould probably try and duplicate that wiring.

thanks for the heater ground trick - I'll have to try it.

Could I use a VR tube for Heater Voltage, and just string the heaters together in series?

Mark

[EvilGenius]

I have a question about the Boozhound amp. I was making a parts list, and was looking at the Hammond 125ESE that he references. It has a frequency response lower limit of 150 Hz. Now, I know that's pretty low, but not as low as it shoulc be for full range.

Are there acceptable replacements that would give a lower range? In the 15W output range, there's the P-T 1615, but the specs are different. What changes would have to be made to incorporate the extended frequency? What about going with the P-T 1620 20W OPT? Most likely a different power transformer would be necessary, right?

[EvilGenius]

bump. anyone? do we need a dedicated Boozhound modification thread?