First tube amp build: Fender Deluxe AB763 style amp (no reverb).

[mikepukmel]

+1 on the Vintage 30. My favorite speaker (once broken in). I think the lack of a break in period could be one reason some reviews claim it's harsh and has too much upper mids. It has upper mids to be sure, but after a good break in period it mellows a bit and there's no harshness at all.

Ohh, thanks for mentioning the break in again. I keep forgetting. yeah, some reviewers seem to have slapped in the speaker, played 3 chords, hated it and switched. I read a blog on a guy that has a really elaborate syste m to break in his speakers, puts a tone gen on and off for days, something about coaxing the tone out of the womb or some artsy thing like that. Might have been some holy water from a temple in the himalayas in there as well.

[pdf64]

My Celestion Classic Lead 80 and Vintage 30 speakers are the least loved of my collection. There's an instant rock tone that bring Marshall to mind but I find them a kinda grating and one trick pony. For cleaner stuff I just can't get them to play nice.
I also took a dislike to a G12M65 that I borrowed for a few days, again there was a brash resonance that seems to work against me.
My G12T75s seems a much better all rounder to me, and they tend to available and reasonably priced secondhand.
All are well played in from my time doing numerous pub gigs with loud drummers! I've still got the speakers, and the tinnitus

My favourite speaker, and one I'm sure would be a great match for a DR, is the Weber 12F50 light dope.
I've no experience of them, but over on TGP the current consensus seems to be the Emi GA SC64 https://www.thegearpage.net/board/in...tions.1871346/
https://www.eminence.com/speakers/sp...?model=GA_SC64

[Chuck H]

For a sweeter tone (read: warmer, less upper mids, softer treble that's a little extended) than the Vintage 30 I like the g12h. I had the anniversary version but most guys like the heritage version, which is reportedly another step in the same direction.

And Pete's right. The Vintage 30 may not be a great mate with a DR. I was just responding to Leo's post and forgot this was a BF topology situation. The g12h would definitely be better in a DR, but there are a ton of speakers that get suggested for that amp. It's all subjective.

[mikepukmel]

Update: Finally!!!! Got everything wired up with the correct parts, checked all of the connections, checked the inside of the chassis with a mag light looking for solder bits and pieces of wire cuttings. Looks ok. got the courage to wire up the big light bulb current limiter and plug it in. Turned the amp on with no tubes installed. Voltages all look correct. No shorts so far, no smoking. 6.3v heater, 350vac input to rect tube. Bias reading -30 to -60 or so.

Akk, fiddled for 10 minutes wondering why no voltage on the filter caps .... with no rectifier tube installed. Heh.

Noticed a definite humming in the power trans when the amp is turned on. Not very loud, but noticeable. Is this to be expected? More like a small buzzing than a hum. After on for 5 or 10 minutes, no heat at all so Im fairly sure no short. Is this a no-load issue?

Next step, check wiring again, plug in the tubes and let her rip? Is it OK to put the bias pot at mid voltage, for this unit it would be about -45?

I don't have a guitar speaker yet, is it ok to run the output into one of my old 8 ohm Klipsch floor speakers to see if I get any sound/smoke/sparks?

[Leo_Gnardo]

Is it OK to put the bias pot at mid voltage, for this unit it would be about -45?

I don't have a guitar speaker yet, is it ok to run the output into one of my old 8 ohm Klipsch floor speakers to see if I get any sound/smoke/sparks?

I'd set the bias at maximum to start. One of your old Klipsch ought to suffice as a load. IIRC they used a CTS or Eminence woofer that was substantial, no buck and a quarter cheapo.

[mikepukmel]

Thanks Leo! Suspension mounts. Welding goggles, check. Hearing protection, check. (Now when did I last have that fire extinguisher charged?)

[mikepukmel]

I'd set the bias at maximum to start. One of your old Klipsch ought to suffice as a load. IIRC they used a CTS or Eminence woofer that was substantial, no buck and a quarter cheapo.

Q: bias max is maximum negative voltage? (Im confusing myself since cw on top of the chassis is ccw from inside.)

[eschertron]

Q: bias max is maximum negative voltage? (Im confusing myself since cw on top of the chassis is ccw from inside.)

Yes. With the Rectifier installed and no other tubes, dial it in to max neg voltage. Then the power tubes should be safe until you bias them 'in'.

edit: ...and of course use a meter to verify, no need to guess CW from CCW!

[mikepukmel]

Yes. With the Rectifier installed and no other tubes, dial it in to max neg voltage. Then the power tubes should be safe until you bias them 'in'.

edit: ...and of course use a meter to verify, no need to guess CW from CCW!

Thanks!!

[mikepukmel]

Progress: got the screws and straps for the chassis in, and mounted the chassis in the cabinet. Its a little crooked, need to fiddle with the holes a bit. The speaker is on the way, will be here Monday, decided not to futz with my poor old stereo speakers. Found a 3 mistakes in the wiring,
- missing a jumper on the phase inverter cathodes
- one ground wire (input jack) is not soldered to the chassis, just flopping around,
- the two signal wires leading from the phase inverter into the output tubes are reversed
- Forgot to order the pilot light bulbs, will put them in an order with the additional fuse holders.
Will fix those, fix the mounts then bolt everything up, waiting on pins and needles until the speaker gets here so I can see if this thing will make SOUND!

[mikepukmel]

Nice cab, well built, but its a little deeper than it needs to be, I think:



Question for everyone: do you put foil on the inside top of your cabinets, above the chassis, for fender style builds, like they did originally?

[Chuck H]

do you put foil on the inside top of your cabinets, above the chassis, for fender style builds, like they did originally?

I do. I skipped doing it for a time on a build where I was just checking fit before more tweaking. That project lingered so I was playing the amp for a time without the foil. The foil definitely helps whenever there's any significant EMF ABOVE the amp.

[mikepukmel]

Thanks Chuck! I will definitely put in a foil card thing. I usually play at such low volumes that stray buzzing and hum are a killer. (As of course, "Tie A Yellow Ribbon" leaking in from the nearest AM radio station ... )

[Chuck H]

I use contact cement and any brand name HD aluminum foil. I don't know if there's a better way, but I figure the contact cement is less likely to go brittle and drop foil on the circuit and the known brand HD aluminum foil is just noticeably heavier than generic On one project I stapled aluminum flashing. Traynor did that with a thin sheet of steel. I didn't like it. Too many edges with the thicker sheet material and staple ends that can make chassis removal and installation persnickety. That, and I worry a staple could loosen and drop into the circuit or that the sheet could develop a vibration rattle. So I'm back to contact cement and HD foil.

[J M Fahey]

What is a Black Shadow now, anyway? I know that the Mesa BS specification changed a lot over the years. At times they sold EV speakers with Black Shadow labels on them, then they sold Celestion speakers with Black Shadow labels on them. Would it be unreasonable to suspect that they've sold Eminence speakers with Black Shadow labels on them? Have they actually done this?

A friend of mine has a MB Mark III head and the matching "half open back" Mesa cabinet, meaning bottom half closed back, top half closed or open back courtesy of a removable back.
Top houses 2 visible "Black Shadow by Celestion" and sounds killer, bright and punchy ... like a Celestion should

Bottom half is supposed to hold 2 Black Shadow EVīs , which of course are invisible.

I had my doubts, because: cones looked generic conical multi ribbed guitar types, not the distinctive curvilinear/exponential/"trumpet bell" EV ones, the cabinet was heavy but not more than a conventional Marshall 4 x 12" (EVs are **heavy**) and to boot cabinet was loud, fat and punchy, but did not show the pants flapping EV bass.

Of course one day "just by chance" I had a Philips screwdriver in my pocket and opened it up: it housed 2 **unlabelled** (not even Black Shadow or Mesa) black stamped frame (not cast aluminum) speakers, 150mm diameter magnets (not 190mm double thickness EV) plus the back plate had the telltale 6mm "Eminence hole" , the one they use to hang the back plate in the cataphoretic black paint tank.

Didnīt have the narrow Eminence barcode label glued to the magnet side (easy to remove if needed) but everything else screamed EMINENCE!!! .

Not a bad speaker at all ... just that my friend payed extra for the "EV loaded" one

FWIW I didnīt tell him ... he loves his amp which by the way has a killer sound, itīs an intermediate model between the original "Blackface amps with gain" and latest Metal meat grinders and he pulls a very nice Power Blues sound out of it, so who am I to rain on his parade?