Amp III

Started by drogulus, April 27, 2017, 07:25:22 PM

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drogulus

Quote from: Toccata&Fugue on July 09, 2017, 09:09:22 AM
Just buy a Bogner Uberschall and be done with it!   ;)


150 watts of pure tube terror.

     No, not that. For high power I'd go for something traditional in the Fender/Marshall/Vox direction. I'm thinking a blonde Showman, or an AC-100 or JTM 45/100 would be about right. I think I'm covered for that with my AC50 clone, that's more power than I can use.
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drogulus

#21

     I decided on Amp IV, and it's going to be based on the little Vox amps like my old Cambridge Reverb. I emailed the builder and we'll talk soon to iron everything out. He did say I was correct in assuming it's very closely based on the original circuits.

     

     Specs:

     15 watts

      ef86 (pentode channel)

      2-12ax7 (triode channel w/top boost)

      12ax7 driver/inverter

       2-el84 power amp (cathode biased, no negative feedback)

       ez81 rectifier

      When I saw the ez81 rectifier tube on the website I knew this guy was serious! Sooo many clone builders don't bother with this, but it's an essential feature of all the 15-18 watt amps made in the olden days by Vox and Marshall. My Cambridge Reverb had it.

     
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drogulus

#22

     Between the idea and reality falls the TopHat Supreme 16. I always think my questions and observations will wear the guy out and I'm almost always wrong. Not once have I engaged with the stereotypical taciturn genius at home on the bench but uncomfortable facing the public. We discussed tubes and speakers mostly (I told him about my JBL-in-a-ring box and he was duly horrified at such an arrangement). Anyway, three weeks and it's mine.
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NikF

Quote from: drogulus on March 19, 2018, 11:46:46 AM
     Between the idea and reality falls the TopHat Supreme 16. I always think my questions and observations will wear the guy out and I'm almost always wrong. Not once have I engaged with the stereotypical taciturn geniuses at home on the bench but uncomfortable facing the public. We discussed tubes and speakers mostly (I told him about my JBL-in-a-ring box and he was duly horrified at such an arrangement). Anyway, three weeks and it's mine.

Looks cool indeed. Do update when it's in yer mitts to let us know how it sounds?
"You overestimate my power of attraction," he told her. "No, I don't," she replied sharply, "and neither do you".

drogulus

Quote from: NikF on March 19, 2018, 01:18:17 PM
Looks cool indeed. Do update when it's in yer mitts to let us know how it sounds?

     It would be just like me to do that.
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snyprrr


drogulus

#26
     I need a speaker that will be as close to ideal as possible for an amp like my new one. It was originally called the Rola G12.

     

     This is an ad from 1936 for the G12, first of its kind. What I want is one of the family of speakers that descended from the original. With only minimal changes this speaker was used by Vox and Marshall in the early to mid '60s. It is still produced today. Vox still uses it, as do a number of boutique builders, like the guy I'm working with now.

     Here is a new one:

     

     It has a bell cover on the magnet, underneath it's like the original.

     
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drogulus


     I ordered a new cabinet from a respected builder:

     

     Mine will be for a single 12" speaker, the above is a 2-12. It will have an oval port in the back so like my other cabs it can be used with a bass.

     My speaker search is coming down to the wire. It will be British voiced alnico, I have the American voiced alnico with my JBLs.

     One possibility was Tayden, but they are insanely difficult to find. The Alnico Blue I discussed above has a power limit I'm not comfortable with. The Celestion Cream alnico can handle power just fine but might be stiff with an AC15 circuit even after break in.

     Right now the best option appears to be the Fane A60 alnico:

     

     The clips I've heard are fine but what really moves me towards this one is that gear fanatics of my general persuasion rate it very highly, even to the point of recommending it for the AC15 circuit my new amp is based on.
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NikF

Quote from: drogulus on April 13, 2018, 07:57:10 AM
     I ordered a new cabinet from a respected builder:

     

     Mine will be for a single 12" speaker, the above is a 2-12. It will have an oval port in the back so like my other cabs it can be used with a bass.

     My speaker search is coming down to the wire. It will be British voiced alnico, I have the American voiced alnico with my JBLs.

     One possibility was Tayden, but they are insanely difficult to find. The Alnico Blue I discussed above has a power limit I'm not comfortable with. The Celestion Cream alnico can handle power just fine but might be stiff with an AC15 circuit even after break in.

     Right now the best option appears to be the Fane A60 alnico:

     

     The clips I've heard are fine but what really moves me towards this one is that gear fanatics of my general persuasion rate it very highly, even to the point of recommending it for the AC15 circuit my new amp is based on.

Nice update. I enjoy reading about your progress with your amps. Most of the considerations you have are way over my head, but I like how you pursue exactly what you require.
For what it's worth, I currently have two amps. One is a reissue of a Deluxe Reverb and the other - the one I use most - a humble Peavey Bandit with the original 12" 'Scorpion' speaker. The DRRI will be sold - the Peavey is enough amp for me.

I've been meaning to ask about the custom built guitar you previously posted (I misidentified the pickups of) and how you find it after living with it for a while.
"You overestimate my power of attraction," he told her. "No, I don't," she replied sharply, "and neither do you".

drogulus

#29
    Look, if you expected me to be outraged by a Peavey Bandit I'm sorry to disappoint you but I'm way too tolerant YOU STUPID BITCH, HOW COULD YOU???

   

    I think you mean my dark green Creston with the fat pickups on it. It's great, unlike any other guitar I've owned. The neck is quite Tele-like through the radius is 12" and the scale is Gibsoneque at 24.75". The pups were designed with the goal of low noise with the highish output of humbuckers but with single coil or even gold foil-ish brightness. It's a Holy Grail kind of thing.

     https://www.youtube.com/v/=VW07kW-DqQ8&list=PLi9nIo1mCPdEHVDSE1GHVq9JfmnXTtT_H&index=2

     Fane speakers were most notoriously used in Hiwatt amps (still are). Those were ceramic speakers that produced an aggressive snarling tone no Celestion could match. The A60 has an extra sweetness alnicos have but if you push them it can get very Live at Leeds.

     https://www.youtube.com/v/lgR4SDxBJAo
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drogulus

#30
     Why would I go to the expense of choosing an alnico speaker over the more common ceramic variety? I'll try to do the short version. In the '50s all speakers had alnico magnets, in the '60s alnico became more expensive and the cheaper ceramics began to replace them in musical instrument amps. Alnico became a premium option in some brands and models. Marshall made the change in the mid '60s. Some great recordings were made just before the change, one of which was the Bluesbreakers album with Eric Clapton, the "Beano" album. Eric used a Marshall combo amp with a pair of Celestion alnico Blues (technically the T530).

     A great speaker builder who makes old school versions of the classic Celestions recorded these clips showing how the phased out alnicos compare sonically with the new ceramics coming in just after "Beano" was recorded:

Ceramic

Alnico

     I hear the alnico as having slightly more compression and not as sharp in the treble. I prefer it.
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drogulus


     I got my new speaker cab today that should be ideal for Amp IV. Take a look:

     

     

     It's pretty, and made of poplar so it's light. I still haven't resolved the question of what speaker to put in it. For now I might put a temporary speaker in for testing.

     
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NikF

#32
Very cool.  8) :)

e: yeah, testing with whatever speaker(s) you have at hand would be worthwhile. Also, I had the soldering iron out recently in order to put the original pickups back into some guitars I found new homes for. And now I need to put the removed pickups into my remaining guitars. In one case it'll mean cutting the pickguard, because the neck pickup isn't an especially common shape, but I'm having someone do that for me.

e2: come to think of it, I could and probably should do it myself with the Dremel.
"You overestimate my power of attraction," he told her. "No, I don't," she replied sharply, "and neither do you".

drogulus

     My temp speaker is an old Utah. I tested the cab with my Starfire bass and to my unsurprise this cab/speaker combo produces great deep bass. It's not at all a bass cab, while my tone ring cab is at all one, but I had the idea that that oval back is a port, reminding me of the late great Ampeg Gemini.

     
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NikF

I haven't seen a Gemini II for years. :) In fact, I'm not sure I've ever heard one in person. I've certainly never played through one.
"You overestimate my power of attraction," he told her. "No, I don't," she replied sharply, "and neither do you".

drogulus

Quote from: NikF on May 02, 2018, 09:17:22 PM
I haven't seen a Gemini II for years. :) In fact, I'm not sure I've ever heard one in person. I've certainly never played through one.

     Ampeg had this philosophy that their amps should be all purpose, and should handle bass because that was the company specialty. Though this model was ostensibly for guitar and accordion it's just as much a bass amp as the legendary B15 that's been in recording studios all over for 50 years.

     

     
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drogulus

#36
     Amp IV is here. I haven't plugged in yet.

     

     Later: My preliminary test was with my 5 string bass. And it looks like my intuition about the oval port was correct as bass output is strong, though I expect there's not much fundamental on the low B.
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drogulus

#37
     This guy Curtis Novak made my Starfire bass pickups and also a split coil pickup for my Esquire clone.

     

     You get the Tele sound and no hum.
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NikF

Quote from: drogulus on May 04, 2018, 07:36:37 AM
     Amp IV is here. I haven't plugged in yet.

     

     Later: My preliminary test was with my 5 string bass. And it looks like my intuition about the oval port was correct as bass output is strong, though I expect there's not much fundamental on the low B.

Very cool. Congrats. Hope you enjoy it. :)
Any closer to a final decision about the speaker?


Quote from: drogulus on May 04, 2018, 01:58:23 PM
     This guy Curtis Novak made my Starfire bass pickups and also a split coil pickup for my Esquire clone.

     

     You get the Tele sound and no hum.

That design looks interesting - and perhaps kind of familiar. Recently I reduced the number of guitars I own, but kept two of the Telecasters. I'm in the process of replacing the pickups. One of them already has a set of Barden pickups, but this is going into the bridge of my favourite Tele -




This is going back in the neck, where I had it for years -




As you probably know, if that were more than just cosmetically a Charlie Christian then it would have the long magnets running parallel to the strings. But this version is (to my ears) still a cool sounding pickup.

The only other thing that's not stock about my Telecasters is the volume pots. I don't understand a lot about this stuff, but maybe you can figure out what I mean by the description; Usually the volume pot increases the volume relatively steadily from 0 to 10. But pots I have installed don't do much over the majority of the range and then suddenly jump with only the tiniest of turn. The reason I chose them is because sometimes I like to play pedal steel riffs and bends with some/all of the attack removed, so with those pots I can more easily pick the strings and use my fourth/pinky finger to turn the volume control at the same time.
That's about it. I'm a simple man with simple tastes and so prefer my guitars that way. ;D
"You overestimate my power of attraction," he told her. "No, I don't," she replied sharply, "and neither do you".

drogulus


     I see your bridge pup is like the Novak. I don't know anything about Charlie Christian pups, except the one you have doesn't look like a Lollar, which is authentic in design, they say.

     https://soundcloud.com/lollarpickups/charlie-christian-pickup-1
     
     I went ahead and ordered the Fane A60 for AMP IV.
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