NAD but it came with a surprise

[Tomm Williams]

Did some more horse trading and came home with a Guild Superbass head and 2x15 cabinet. Not certain of the year as Guild apparently wasn't too good keeping records. Best I can tell, it should be mid to late 60's? This head came with the 8417 tubes and when I opened the cabinet was when I got my surprise.

First the good---- it came with a pair of JBL D140f's which I've discovered was an option.

The bad---- one of the 140's was just the basket and cone!!!! The entire magnet assembly was missing!!!

I'm going to contact the seller ( non original owner) and see if they know where the assembly is located. If all else fails, is this a part that can be found or is it easier to buy another 140?

 

Nevermind...............a little research shows this is a "passive radiator" not a hacked up speaker, I guess I've never seen one before. Amp sounds really good and both channels are pretty easy to dial in a guitar tone unlike the bass channel on a Bassman. Love the "Jetsons" look to it.

 

[DeepEnd]

"Passive radiators" used to be big in home audio speakers. I think EV was the first company to use them. The idea was to replace a very, very long port. I've never seen one in a bass amp but that doesn't mean much. Anyway, Happy New (Oddball) Amp Day and, once again, you find the coolest, strangest gear. My hat is off, sir.

[WRGKMC]

My first bass player back in my high school days has a Thunderbass amp. His was the blackface series that came out after those tans. I think they just stuck the head in a different cab. Had the same two tone grill cloth except his had two separate 15" cube cabs like the one below.

 

I always suspected there was something wrong with is amp because it didn't have much volume and distorted when it was turned up. The speaker cabs had either JBL's or Altecs however. Just the head sounded bad. My 50W Bassman used for guitar overpowered the bass badly when we played together.

 

 

 

 

 

[Tomm Williams]

I've been Googling info all week on this amp and solid info is just about non existent. Opinions are all over concerning most every key topic. Years of production, design changes, output, etc...

Then there's the subject of the Quantum model which looked exactly the same as the standard model except for a sticker on the front identifying it as such. This model supposedly had 200 watts but even this is disagreed upon from thread to thread!! Mine has the 8417 power tubes which some say indicates it's a Quantum, others say not so. Mine is also the 4 preamp tube model (some had 3) which indicates a Quantum. Again, this is not without disagreement.

All I can tell is this, it's louder than my Bassman and quite frankly sounds better but that could be the cabinet with the D140. The bass channel is much nicer for guitar than my Bassman. By jumping the two channels, I get an overall tone I like much more.

I've yet to run my pedals through it so I'm not done testing at the moment. Even if somehow it takes them horribly, this is still one sweet amp for clean tones. And although admittedly it's a poor reason to buy an amp, the look of it hooked me when I saw it.

[WRGKMC]

The original Sylvania 8417 tubes were rated up to 70W each. Some others are rated up to 35W. If they are vintage they may produce up to 100W from a single pair, but I'd think it may be run a bit cooler for clean bass tones. Its probably going to be louder then the Bassman. Of course the JBL gives you a nice SPL boost too.

 

The Power tubes are a bit hard to find and pricy too. Tube Depot has them for $84 each for singles. Its unlikely you'd find matched sets.

I read a bit about substitutes. Some say EL34's might work. Others say 6550's or KT88's but you'd have to mod the amps circuitry. http://tube-and-valve-electronics.co.uk/product_information/8417_tube_data_Replacing_8417_with_6550_or_KT88.asp

 

I know 6CA7's can take the higher plate voltages. I'd have to research weather they might work. Its Not that this is imperative because your amp is obviously working

[Tomm Williams]

The 8417's currently in it are Sylvania's and it still has "Guild" branded 12AX7's so I suspect all the tubes are original. I've been playing through both the Guild and the Bassman all morning and formed an opinion concerning the difference in sound. This might be due primarily to the difference in cabinets (D140F vs. V30 & Cannabis Rex) but the sound of the Guild/140 is simply more clear, articulate and detailed. Now I'm not certain how much of this is also the amps but it must have some effect here. As the Guild head and cab are 8ohm and the Bassman is a 4ohm, I'm reluctant to switch the heads to see what the results might be. I'm not implying the Bassman sounds bad...........quite to the contrary !!!! it's just that I'm hearing things with the Guild I've never really heard before. I'm not sure if this might be what some people call "Hi-Fi Sounding" ? With the Bassman I prefer to jump channels via a Lehle A-B-Y pedal. In doing so, finding a good tone took a bit of work as the bass channel was a little tricky finding a tone that wasn't a bit muddy. With the Guild bass channel, it was easy to dial in a nice blend of the two with some added (but articulate) bottom end.

[WRGKMC]

You can run a Bassman at 8 ohms with no issues. Just don't go any higher. I bought My 67 Bassman Blackface new with two 16 ohm Altecs (8 ohm total) and have run it that way for 49 years. I did run it at 16 ohms for awhile and it ate up tubes within a months, So long as you don't go over 8 you're fine. Those transformers are highly durable.

 

If that speaker is a D140F its a 16 ohm speaker so it shouldn't be used with the bassman

 

The reason you're hearing more detail with that amp is likely the JBL is because it has an aluminum dome. Its got a response up to 6Khz. Finding specs on the old speakers is really tough. They didn't print allot of that stuff so you really got to dig.

 

 

 

From the guy who designed the speaker

 

There was no taken 1xx series at the time, except for the 13x and the 15x, so I chose to try to number the series according to frame size, hence the D110F, and the D120F. I couldn't change (and wouldn't change) the D130, since it was already so popular. That left the 15" bass speaker; what to call it? It would cause confusion to name it after one of our existing models, so I simply chose D140F as the name. I used an aluminum dome on the D140F more for product identification, but it actually did help allot, and it allowed me to continue with the "F" series as an aluminum domed speaker series. JBL never published T/S parameters for the "F" series to my knowledge. They were long out of production by the time that JBL adopted T/S design.

 

 

 

 

 

This 2130 is nearly identical to the D130's which is a full ranged speaker. The 140's are bass/keyboard speakers so the frequency response may not get as high as the 130's due to the heavier materials but its still well above the competition at the time. Your cab only needed one speaker for that head and you still had a good 50W or more spare headroom.

 

 

I have two newer JBL,s a 15" and an 18" and both make any head I use sound better then other cabs.

Compared to the Eminence I have its like night and day for volume and detail. If I run them side by side its like the Eminence isn't even plugged in.

 

I used to have a B52 cab which came with the Black Magnet Eminence. It wasn't bad when run with various heads. I bought a pair of Re-coned 15" Altecs and put them in there and stuck the Eminance in some A7 cabs I had for vocals. The Altecs blew chunks over those eminence. I could gig with my little Bassman head without a problem and when I used my 100W V4B head I'd drive the sound men and club owners completely bonkers. We were using a 5000W PA then and my amp un-miked dominated the sound, and I only ran it at 50%.

 

Theres a reason JBL's and Altecs were used in nearly all sound systems and pro amps back then. Its because they literally blew the competition away.

 

As far as jumping channels, I tried it long ago and thought it sucked for tone. It created a weird phase bump that never sounded very good. I can do much better using any number of pedals if I need shaping.

[Phil O'Keefe]

"Passive radiators" used to be big in home audio speakers. I think EV was the first company to use them. The idea was to replace a very' date=' very long port. I've never seen one in a bass amp but that doesn't mean much. Anyway, Happy New (Oddball) Amp Day and, once again, you find the coolest, strangest gear. My hat is off, sir.[/quote']

 

Mackie was doing something similar with their HR series studio monitors. I'm not sure if they still have the passive radiator on the back of the latest versions of them though.

 

Cool Guild Tomm! Nice that it came with the factory-optional JBL. As WRGKMC said, that's probably a big contributor to the clean, detailed sound.

[DeepEnd]

Mackie was doing something similar with their HR series studio monitors. I'm not sure if they still have the passive radiator on the back of the latest versions of them though. . . .

According to this, they do: http://mackie.com/products/hrmk2-series.

 

[Phil O'Keefe]

According to this, they do: http://mackie.com/products/hrmk2-series.

 

Cool - thanks for clearing that up for me.