Need PA amp conversion help

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...If you like that sound...
It's not the genre I like. What makes Lake Street Dive for me is their rhythm section: Bridget Kearney's awesomely tight, incredibly groovy, extremely creative bass lines, and Mike Calabrese's always impeccable, perfect drumming.

Sometimes those two sound so fantastically tight that it's almost as if they share one heart and one pulse. Awesome!

I know Rachel Price is the one who usually gets all the attention, and she certainly does have a great singing voice, with lots of power and excellent pitch. But I really wish she'd put some dynamics into her singing. She's always flat out, always turned up to eleven, always shouting as loudly as she can. For me, that brings on ear-fatigue and boredom after a few minutes.

So it's not so much the genre that I like - it's the awesome musicianship of some of the members.

It's the same story for me with, say, this Molly Tuttle song: YouTube

I don't like that genre at all, but Ms. Tuttle's incredible guitar chops and pretty voice make even dreary lyrics and stale chord progressions sound good, at least for a while. I have zero flat-picking skills, but I find it very impressive what good bluegrass players can do with an acoustic guitar.


-Gnobuddy
 
So it's not so much the genre that I like - it's the awesome musicianship of some of the members.
Got ya! Fair enough, I've found myself enjoying good musicianship within genres or contexts that I don't necessarily care for as well. Genres are just for helping classify and sell records anyway, good music is good music whether its jazz fusion, blue grass, heavy rock, R&B, whatever :D

I don't like that genre at all, but Ms. Tuttle's incredible guitar chops and pretty voice make even dreary lyrics and stale chord progressions sound good, at least for a while.
She's definitely got the goods! That's a near perfect performance :sing:

Ever listen to Wilco? One of my all time faves, the musicianship is often technical, sometimes tight, but sometimes very loose, and certainly never boring lol
This would be one of their more straight forward songs, but has a beautiful melody carrying it :hphones:
YouTube
 
Genres are just for helping classify and sell records anyway
Exactly, right? Some non-musician draws borders and walls around every song, so they can figure out how to market it, and whom to sell it to. But a lot of the time, those artificial divisions don't really fit very well. Where does violet stop and indigo begin in the spectrum? And who decided there were only seven colours in the rainbow, no more, no less?

My wife is an artist, and like many other visual artists, she could easily pick out fifty different colors there, probably a lot more. I've been to a really good bead store with her a few times, and it was quite something to see several shelves full of each size of "yellow" beads, but in forty or so different "shades".

Well, that's how us muggles see them. But to an artist's talented eyes, every one is a different individual colour.
Ever listen to Wilco? One of my all time faves
Thanks for the tip! I really enjoyed that.

I wasn't familiar with these guys at all. Somehow, I'd never even heard of them until now. I'll definitely be looking up some more of their songs after work tonight!


-Gnobuddy
 
Thanks for the tip! I really enjoyed that.

I wasn't familiar with these guys at all. Somehow, I'd never even heard of them until now. I'll definitely be looking up some more of their songs after work tonight!
Glad you enjoyed it :) Fair warning, I did say this was one of their more straightforward songs. Not all of their music is as easy listening, but it's never boring lol. If you ever get a chance to see them live do it. The lead singer Jeff Tweedy is on a solo tour right now and he's got some really great stuff on his own too. More subdued and acoustic driven but very good.
 
Not all of their music is as easy listening
What I noticed immediately is that these guys actually listen to each other as they play, and leave each other sonic space. And they play with dynamics.

Clearly not a Pro Tools + Auto Tune creation, then, but a band that's spent lots of time playing together until the individual musicians gelled into one musical ensemble. Actual musicians, with actual chops, and actual talent, and actual playing experience.

These guys, I have to listen to some more. They may or may not end up a personal favourite, but they already have my respect as a band.


-Gnobuddy
 
What I noticed immediately is that these guys actually listen to each other as they play, and leave each other sonic space. And they play with dynamics... they already have my respect as a band.
My man!:cool: See, I knew you had good ears! Haha ;)

In other news, I may be able to carve out some time for working on the amp this weekend. With some luck hopefully I can make enough progress for another update on Monday. We’ll see how it goes :xfingers:
 
So I was able to do some work on the amp on Sunday, but did not finish as much as wanted. I have all of the old TS circuitry out and I got the capacitor and 2 resisters in where the old bass control was. Next weekend I will still have to wire in the new TS and separate the cathodes of the dual triode that are tied together. Hopefully I will be able to get all that done and have another update and video of how it sounds.

In other related news I discovered something interesting while working on these updates Sunday. At the first 6FQ7 dual triode in the signal chain, where I'm making all these changes, the triodes were originally wired in backwards. Meaning where the schematic shows connections at pins 1, 2 & 3 in the amp those connections are actually at pins 6, 7 & 8. And the reverse was true, where the schematic shows connections to pins 6, 7 &8, in the amp those connections are actually at pins 1, 2 & 3. It's definitely the original soldering and wiring connections so this happened when the amp was manufactured in the 1960's. I know it doesn't matter to the amps functionality which triode is wired in first as long as the anodes, cathodes and grids are connected to the correct circuitry components, but I couldn't believe this made it past the original inspection lol. Anyone else ever run into something like this or is it actually a regular occurrence and I just haven't happened across a switch up like this before?
 
...I couldn't believe this made it past the original inspection...
I have no experience with equipment of this vintage, but I wouldn't be surprised if it turned out the assembler followed the layout diagram as given to him/her...and it was a case of the published schematic not agreeing with the mechanical layout. As you say, this wasn't really a mistake, since it resulted in a correctly working product.

This sort of thing is one reason printed circuit boards were such a wonderful invention. Originally used in top-secret miniature vacuum-tube electronics (aka the "proximity fuse") built into WWI cannon-shells(!) that gave them the ability to sense a nearby metal aircraft and detonate without having to make actual contact, the PCB made its way into consumer electronics a decade or two later. And assembly error rates at the factory plummeted.

Back to your discovery, I remember reading that the domestic (American) auto manufacturers averaged several - IIRC more than ten - manufacturing and assembly defects per car in the 1960s/ 1970s. They had even talked themselves into believing that nobody could possibly do any better. So they were shell-shocked when they found out the new and then much-derided imported Japanese cars from the likes of Honda and Nissan/Datsun were averaging zero defects per car.


-Gnobuddy
 
This sort of thing is one reason printed circuit boards were such a wonderful invention. Originally used in top-secret miniature vacuum-tube electronics (aka the "proximity fuse") built into WWI cannon-shells(!)
Nice historical note! However is is possible you meant WWII ?:scratch2: I'm pretty sure that's when the proximity fuse technology was developed in tandem by British and Then American developers for use in antiaircraft shells and the like. I'm not an expert but I was a history major in college lol:shy:

Back to your discovery, I remember reading that the domestic (American) auto manufacturers averaged several - IIRC more than ten - manufacturing and assembly defects per car in the 1960s/ 1970s. They had even talked themselves into believing that nobody could possibly do any better. So they were shell-shocked when they found out the new and then much-derided imported Japanese cars from the likes of Honda and Nissan/Datsun were averaging zero defects per car.
Again nice historical point! No bones to pick on this one :spin:
 
However is is possible you meant WWII ?:scratch2:
I did indeed. My apologies for the typo! :eek:

I've never been great at history, but have been interested in technology (including aircraft) since I was very little, and the technology gap between WWI and WWII was so enormous that even I can't get those two screwed up. But, apparently, my disobedient fingers can still omit an "I"!

My typo made me curious. Lee De Forest invented the triode several years before the *first* world war, so were there any military applications of vacuum tubes during WWI? Wikipedia has this fascinating sentence to offer about early production triodes: "...the French type 'TM' and later the English type 'R' ...were in widespread use by the allied military by 1916."

So, no PCBs or proximity fuses (or aircraft capable of carrying cannons!), but vacuum tube electronics apparently did play a part in the first world war. An odd bedfellow in a war that also featured cavalry.


-Gnobuddy
 
My typo made me curious. Lee De Forest invented the triode several years before the *first* world war, so were there any military applications of vacuum tubes during WWI? Wikipedia has this fascinating sentence to offer about early production triodes: "...the French type 'TM' and later the English type 'R' ...were in widespread use by the allied military by 1916."
Sounds right to me. Vacuum tubes were definitely in use for radio transmission during WWI. If memory serves the first messages between allies of the armistice reached with Germany to end the war in Nov. 1918 were sent out by radio transmission.

So, no PCBs or proximity fuses (or aircraft capable of carrying cannons!), but vacuum tube electronics apparently did play a part in the first world war. An odd bedfellow in a war that also featured cavalry.
Indeed! To those of us looking back, WWI can seem an odd war in many similarly sorts of ways. That era saw the advent of many new technologies, and also saw civilization on the cusp of many others, but at the same time all countries involved were hanging on to antiquated tactics and practices that would soon be phased out. It's an interesting period to study for sure :)
 

PRR

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Joined 2003
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Radio for ships had been common since the Titanic sank; it became mandatory for ships to maintain a listening-watch proportional to their size.

Early radio was not tube-based. Various wacko things were used as detectors. Early transmitters were spark-gap. By WWI tube detectors were getting used but large transmitting tubes were still in the future.

When the USA faced coordinating actions on the far side of an ocean (and the prospect of undersea telegraph cables possibly being disrupted), 6+ days away by ship, they essentially nationalized all radio for government use. Marconi's loyalties were unclear so the Gov seized the Alexanderson Alternator (cleaner than a spark-gap) which had been ordered but not shipped, installed it at New Brunswick NJ (on a bluff in sight of the ocean but out of range for coastal artillery).

Also all tube production was dibbed for Gov need, and all amateur radio shut-down. When the Gov tried to order radios (including tubes which were just becoming useful) they discovered you could NOT make a radio without stepping on too many patents. The Gov would do that in war-time, but recall that the US was "not at war" for several years, just "assisting".

The up-shot was that the Gov demanded that "all" radio patents be pooled and licensed at reasonable rates to any applicant. WE GE Westinghouse and others agreed in principle by forming a new office called "RCA". At first just paperwork, but when Sarnoff rose to the top RCA took-off and became the major electronics developer for the next 50 years.

If you have trouble sleeping: Capital Moves, Cowie, tells the story of labor at RCA. Considering his main premise (Capital will move globally to find docile low-pay girl workers), he omits a major period. Camden was already a factory town, and RCA bought the Victor works specifically to get a ready-made manufacturing operation. Cowie says almost nothing about Victor. Did they use girl labor? Did they have labor trouble? After omitting this context, he goes into great detail about RCA's labor relations and later troubles. Cunningham appears only to vanish again, though I suspect Cunningham was a key player in labor relations and the brutal strikes are why he left RCA. And that's just the first few chapters-- RCA moved to Indiana and Memphis and then Mexico, before Sony et al ate RCA's lunch (well, that and Selectavision).
 
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When the USA faced coordinating actions on the far side of an ocean (and the prospect of undersea telegraph cables possibly being disrupted), 6+ days away by ship, they essentially nationalized all radio for government use. Marconi's loyalties were unclear so the Gov seized the Alexanderson Alternator (cleaner than a spark-gap) which had been ordered but not shipped, installed it at New Brunswick NJ (on a bluff in sight of the ocean but out of range for coastal artillery).

Also all tube production was dibbed for Gov need, and all amateur radio shut-down. When the Gov tried to order radios (including tubes which were just becoming useful) they discovered you could NOT make a radio without stepping on too many patents. The Gov would do that in war-time, but recall that the US was "not at war" for several years, just "assisting".

The up-shot was that the Gov demanded that "all" radio patents be pooled and licensed at reasonable rates to any applicant. WE GE Westinghouse and others agreed in principle by forming a new office called "RCA". At first just paperwork, but when Sarnoff rose to the top RCA took-off and became the major electronics developer for the next 50 years.
I think you've got some of the basic idea here PRR, but the timeline looks a little confused. I have several books and publications at home I could reference, (remember actual references, before wikipedia? lol) but from memory right now President Wilson didn't order a ban on civilian radio transmission until the US officially entered the war in 1917. There was an executive order earlier (1914 or 1915 I think?) to enforce radio neutrality by monitoring and censuring overseas transmission, but civilian radio transmission within the continental US was otherwise mostly unimpeded until 1917. It fell to the Navy to uphold this order and censure all radio messages sent to and received from overseas. That's what got the American Marconi company in trouble with the US gov. initially. The parent companies of Marconi America were in Europe (London actually I think) and the US had worries fair neutrality would not be maintained in all of Marconi's broadcasts. The Navy found cause to censure them on more than one occasion and Marconi tried to fight it in court. In April 1917 the US officially entered WWI and either seized or shut down all civilian Radio transmissions equipment in the country. At that point the Navy took control of an Alexanderson Alternator at a Marconi transmission site on the east coast (possibly the one in NJ you mentioned?) and began using it for US military purposes.
After the war the Navy still had a bone to pick with Marconi and didn't want what was essentially still a British owned company to be the foremost in radio transmission in the US. They talked GE into ceasing sales of equipment to Marconi, then buying out Marconi America's assets and starting their own radio transmission co around 1919. This eventually became RCA.

Again you've got this information all there more or less, just needed some timeline. Thanks for posting the info, I love history and this is a fun era to study!
 
...remember actual references, before wikipedia?
In the UK, there is the "Domesday book", which Wikipedia describes as "a manuscript record of the "Great Survey" of much of England and parts of Wales completed in 1086 by order of King William the Conqueror." Still readable more than 900 years after it was written. Elsewhere in the world, there are written documents going back several thousand years, still readable.

Meantime, I read an article about efforts in the early 2000s to rescue an expensive and significant astronomy documentary originally released on Laserdisc circa 1980 or so (by the BBC, I think.) The plan to read the original data and convert it to then more contemporary formats hit a massive roadblock immediately - nobody could find working Laserdisc hardware to read the still immaculate discs, a technology barely 30 years old at the time.

As "actual references" - written records on paper - go away, I think we're going to lose vast amounts of our history in very short order. Incredibly significant early software on punch-cards is already lost forever. Microsoft will be a short blip in history looking back from a few centuries in the future, and almost everything in proprietary Word format will be lost (including laws of the land, and civil records of birth, death, marriage, land ownership, etc.)

And Wikipedia? HTML is an open format, but I'm betting it won't last a century, either.

...Alexanderson Alternator...
Thanks to both of you for mentioning this device. In all the years I've been reading about electronics and technology, I'd never heard of it. Simple though the math is, it never occurred to me that an alternator could have enough poles and spin fast enough to generate RF frequencies (as anyone who's installed car audio can tell you, auto alternators generate frequencies that don't even get to 1 kHz.)


-Gnobuddy
 

PRR

Member
Joined 2003
Paid Member
This is the "New Brunswick" building, actually just over the border into what used to be called Easton, now Somerset/Franklin. Distinctive style. This was the office. The transmitter buildings were torn down in 1950s and 2002. The guard rail and block walls are new, added when a self-storage facility was built behind this building.
 

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I've wondered whether to bring this up on this thread or not, but I guess now is as good a time as any, while the thread is relatively quiet.

Several years ago, I stumbled across a guitar amp forum thread about a DIY guitar amp design christened the Tweed Overdrive Special, or TOS for short.

The TOS has an interesting layout: the clean channels uses the usual 12AX7 (two triodes). But then the clean signal is attenuated down and fed through a third triode, and then through a small-signal pentode, so that the "drive" channel actually has four gain stages (triode, triode, triode, pentode.)

Additionally, the tone controls are similar to the early Fender Tweed one-knob circuit. The designer(s) say this was for improved usability - the amp already has several knobs and switches. But it also turned out that, without the usual Fender / Vox / Marshall mid-frequency notch, the sound of this amp tends to "sit well in the mix".

At any rate, it is an amp that doesn't sound like yet-another-Fender (YAF) or yet-another-Marshall (YAM). It uses a small-signal pentode in the preamp. And it generates most of its tone in the preamp, so it can be turned down for low-volume playing. So I thought E-moose might find it interesting.

Here is the original 2010 thread:Tweed Overdrive Special

Here are two soundclips:
1) SoundClick player

2) SoundClick player

I'll add that the design of the FX loop in this amp almost makes my gut tie itself in knots; taking a signal of up to 250 volts peak-to-peak, running it into a 1-meg pot, and then feeding the FX loop from the wiper of that pot, is a terrible idea for several reasons.

The FX loop design can be fixed, though, if there is any interest in this rather unusual amp.


-Gnobuddy
 
It uses a small-signal pentode in the preamp. And it generates most of its tone in the preamp, so it can be turned down for low-volume playing. So I thought E-moose might find it interesting.
That is interesting! I could see some parallels to my amp, with the pentode in the preamp. But also a lot of differences, it's a unique looking design for sure.

I'll add that the design of the FX loop in this amp almost makes my gut tie itself in knots
I see what you mean! Lol, not the most ideal fx loop design for sure.

I've looked around at what other people have done with pentode preamp designs and hadn't seen this one yet. I don't think there are any applications or ideas used in this amp that I'd like to implement in mine, but it's an interesting design to look at none the less. Thanks for sharing!:up:
 
While we're on the subject, here's a schematic of another amp with an EF86 pentode in the preamp. I'd looked into this one thoroughly whilst researching for what changes I could make to the tone-stack on my amp. Lots of Youtube videos on this one out there since it was a mass produced amp for several years before being discontinued. There are some similarities in concepts and ideas here to what was already happening in my amp. If the Fender TS mod doesn't work out on my amp, something like this may be the fallback I go to. But I'm hoping the Fender TS works well haha! If I can finish those changes this weekend we'll find out soon enough :xfingers:
 

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