dave251 Posted March 7, 2002 Share Posted March 7, 2002 Myles suggested I post this thread over here due to some inhospitable reactions to his posting over at HC...thanks for the opportunity, Myles.... We've gathered all the components for the first "electroCoustic" amp. My buddy Brett H. up KC way will start assembly this weekend. We're going to try something a bit radical here...just to see if it works. Those of you who have either played or listened to my instruments know that I'm after a "clean" sound, truly a "hi-fi" tone, with all of the harmonic richness one can find in a good acoustic. So here's the radical part....essentially we are building a 1935 era amp...this thing has only three tubes....a 5U4 rectifier, 6SN7 for the preamp/driver, and a Western Electric 300B for the power tube...now it's only going to be about 10watts total output...but we'll be plugging into a properly ducted JBL E130 cab...with any kind of luck at all, we won't need tone controls. We both felt there was enough at the guitar we shouldn't need it. We both run our guitars pretty much flat through our respective PA systems.... What this does for us is twofold....simplifies the amp construction, and since we have so few gain stages, it SHOULD make the guitar that much more touch sensitive. And that's what we're shooting for. We wanted an amp with the shortest signal path possible...from the hands to the speaker...just as simple as it can get without actually being a true "acoustic". Hopefully, we'll be able to get loud enough for a jazz combo...be able to compete with a grand piano and sax, while still being "acoustic" enough for a modern string band, ie, fiddle, banjo, dobro, drummer with a reasonably light touch, etc.... I'm real excited about the project....although it is VERY expensive for the big ass output transformer and the 300B tube, we were willing to take the risk on an untried design. I welcome comments and flames regarding the project as I'm sure there is something I'm not seeing or have thought of... PS: For those of you who haven't heard my guitars, I have a CD demo availible, which includes some fine playing by Jim Soloway on his 7 string electroCoustic... Thanks.... Dave Wendler Instruments Link to comment Share on other sites More sharing options...
Gabriel E. Posted March 7, 2002 Share Posted March 7, 2002 Sounds real interesting. Can you get any simpler? Have you checked out Ampage ? Very helpful and supportive people there who would be interested in hearing your concept. What filter caps are you using? Sounds like Solens might be the way to go for this project. "You never can vouch for your own consciousness." - Norman Mailer Link to comment Share on other sites More sharing options...
JamesPeters Posted March 8, 2002 Share Posted March 8, 2002 This is a single-ended class A amp we're talking about...I mean, that one power tube only has one triode, right? If so, why the tube recto? There won't be any sag to speak of in the circuit, it being class A (drawing full current constantly). If you want to lower the B+, just build it into the design (ie. add an extra diode in series with your diode rectifier stage, etc.), that way you'll save bucks when it comes to having to buy parts. No point in spending $20 or so for a rectifier tube you don't need, and the extra 5V filament supply for the tube rectifier, having to wire in the socket, etc. The P1 and High Octane on the AX84 site had their tube rectifiers removed from the designs for this reason--there was neglible difference from tube to SS rectifier. Some wanted lower B+, and they found simple ways of doing that. http://petersamps.com Handmade tube guitar amps Link to comment Share on other sites More sharing options...
JamesPeters Posted March 8, 2002 Share Posted March 8, 2002 Oh yeah, have you chosen an OT for that? The Hammond 125ESE (part of the 125SE "single-ended" series) is great--lots of low end, smooth highs, and won't saturate until it gets a lot of current. Judging by the tube data sheets for the 300B, it looks like you're going to be under by a good margin (60mA for 400-450V B+, and the 125ESE could do 80mA). http://petersamps.com Handmade tube guitar amps Link to comment Share on other sites More sharing options...
Dak Lander Posted March 8, 2002 Share Posted March 8, 2002 This idea sounds too cool. I'm thinking, if it works, it'll work for a good acoustic too. Am I off base there? Our Joint "When you come slam bang up against trouble, it never looks half as bad if you face up to it." The Duke... Link to comment Share on other sites More sharing options...
JamesPeters Posted March 8, 2002 Share Posted March 8, 2002 I'm sure it's not the first time a tube amp has been used to amplify acoustic guitar, lol! But I don't know if it's what you are specifically looking for. After all, my favorite clean sounds right now are the new Peavey Bandit (the newest ones, with the red trim) and the Roland JC120--both are solid-state amps. As for acoustic amps, they'd both do I guess, but I find a good mic, good compressor/EQ/direct box is all I'd need, then go right to the board. http://petersamps.com Handmade tube guitar amps Link to comment Share on other sites More sharing options...
dave251 Posted March 8, 2002 Author Share Posted March 8, 2002 Originally posted by daklander: This idea sounds too cool. I'm thinking, if it works, it'll work for a good acoustic too. Am I off base there?The amp itself will probably work just fine, kind of a "purist" esoteric approach. However, a two way HIGH EFFICIENCY speaker cab would probably be a better choice for the cab. The amp will be specifically designed for our guitars and is really a "living room" or studio amp...with only ten watts, weighing in at about 50 lbs, and using a giant, fragile power tube, we don't think it's the kind of amp to be moving around a lot. However, it's the simplicity of the thing that appeals to us; I come from an acoustic guitar/instrument background, although I hold a patent in the field of acoustic amplification and worked as an engineer at an electric guitar factory. After all of the emphasis on "control" and diversity of tone "after the fact"...I was looking for a SIMPLE electric guitar with all of the subtle tonal nuance that an acoustic has to offer. While I wouldn't say the guitars sound "like an acoustic", they do capture that touch sensitivity and dynamic response...and that's what we're after in the amp--something VERY simple that gets the ears and hands CLOSER to the instrument. The guitars work, and work well through standard PA systems and acoustic amps. But as always, as a designer, I'm looking for more... Dave Wendler Instruments Link to comment Share on other sites More sharing options...
dave251 Posted March 11, 2002 Author Share Posted March 11, 2002 ________/\________ Dave Wendler Instruments Link to comment Share on other sites More sharing options...
strat0124 Posted March 11, 2002 Share Posted March 11, 2002 Originally posted by dave251: ________/\________...that looks like an A scope, with a target in the range gate!!!!!!!! Down like a dollar comin up against a yen, doin pretty good for the shape I'm in Link to comment Share on other sites More sharing options...
strat0124 Posted March 11, 2002 Share Posted March 11, 2002 Reminds me of the Epiphone 10 watter, basically one preamp tube, one power tube. I'm a huge fan of small tube amps, so if it sounds good and inexpensive enough, I'd be a potential customer. Down like a dollar comin up against a yen, doin pretty good for the shape I'm in Link to comment Share on other sites More sharing options...
myles_rose Posted March 12, 2002 Share Posted March 12, 2002 Originally posted by dave251: Myles suggested I post this thread over here due to some inhospitable reactions to his posting over at HC...thanks for the opportunity, Myles.... We've gathered all the components for the first "electroCoustic" amp. My buddy Brett H. up KC way will start assembly this weekend. We're going to try something a bit radical here...just to see if it works. Those of you who have either played or listened to my instruments know that I'm after a "clean" sound, truly a "hi-fi" tone, with all of the harmonic richness one can find in a good acoustic. So here's the radical part....essentially we are building a 1935 era amp...this thing has only three tubes....a 5U4 rectifier, 6SN7 for the preamp/driver, and a Western Electric 300B for the power tube...now it's only going to be about 10watts total output...but we'll be plugging into a properly ducted JBL E130 cab...with any kind of luck at all, we won't need tone controls. We both felt there was enough at the guitar we shouldn't need it. We both run our guitars pretty much flat through our respective PA systems.... What this does for us is twofold....simplifies the amp construction, and since we have so few gain stages, it SHOULD make the guitar that much more touch sensitive. And that's what we're shooting for. We wanted an amp with the shortest signal path possible...from the hands to the speaker...just as simple as it can get without actually being a true "acoustic". Hopefully, we'll be able to get loud enough for a jazz combo...be able to compete with a grand piano and sax, while still being "acoustic" enough for a modern string band, ie, fiddle, banjo, dobro, drummer with a reasonably light touch, etc.... I'm real excited about the project....although it is VERY expensive for the big ass output transformer and the 300B tube, we were willing to take the risk on an untried design. I welcome comments and flames regarding the project as I'm sure there is something I'm not seeing or have thought of... PS: For those of you who haven't heard my guitars, I have a CD demo availible, which includes some fine playing by Jim Soloway on his 7 string electroCoustic... Thanks....dave251 .... Well, all I can say is when you have a few prototypes, put me on the list. I'll take one in a flash. First off, you picked some really terrific tubes. Second, using a 300B in high end mono amps, at less than 5 watts, when using compression drivers, is louder than any Marshall stack. You're use of a JBL would give you immense efficiency. Maybe think of 4 JBL LE-8T's in an open back cabinet .... 1 watt in = 107db out at 1 meter. Compare a celestion at 85db and ..... 1 watt = 85 db 2 = 88db 4 = 91db 8 = 94db 16 = 97db 32 = 100db 64 = 103 db (woops .... so much for a Marshall 50) 128 = 106 db (so much for a Hiwatt or 100 watter) 256 = 109 db ..... and this is where your amp would come into play. You are looking at 105db or so with your JBL at 1 watt 2 watts = 108db 4 watts = 111db 8 watts = 114db Not to mention the amazing articulation of the 300B tube. Like I said .... sign me up for one! I love class A single ended amps such as the Univalve. When you look at their success, I think more of it has to do with it being a great sounding amp and less has to do with its versitile nature. In a non-studio environment, most folks get a favorite setup and stay with that it seems. Your 300B based amp with a 6SN7 (one of the best sounding preamp tubes EVER), would be pretty amazing. There are Hi-Fi amps much like this on the market, but they are terribly expensive for the most part. If somebody could make something more commercial without all the fancy wood and chrome or brass plating, that would sell for a nice price, you'd be run down with business after the word gets out. Now, if I could just afford the amp plus a L-5 or ES-175 with a single soapbar pickup .... Look pretty closely at your transformer design. This is ultra important, and many times makes the difference in the Hi-Fi world between a $500 amp or a $15,000 amp. ... that, and a few other items Please keep me in the loop on this. If you need somebody to talk to your "bank" for you guys getting financing, I'd be more than happy to do so. I have about 35 years of doing this sort of thing and know a person or two that would be more than happy to be bank references too. Good luck .... Regards, Myles Myles S. Rose www.guitaramplifierblueprinting.com www.la-economy.blogspot.com www.facebook.com/mylesr www.twitter.com/myles111us Link to comment Share on other sites More sharing options...
JamesPeters Posted March 12, 2002 Share Posted March 12, 2002 At the risk of spamming, do you think you'd want to look at one of my amps Myles? Feel free to email me if you like. http://petersamps.com Handmade tube guitar amps Link to comment Share on other sites More sharing options...
myles_rose Posted March 12, 2002 Share Posted March 12, 2002 Originally posted by JamesPeters: At the risk of spamming, do you think you'd want to look at one of my amps Myles? Feel free to email me if you like.JamesPeters; I'd be more than happy to give an amp of yours a look. You should post in the "ask Myles" subject so I can find the post as I get email from when there is a post over there. Regards, Myles Myles S. Rose www.guitaramplifierblueprinting.com www.la-economy.blogspot.com www.facebook.com/mylesr www.twitter.com/myles111us Link to comment Share on other sites More sharing options...
dave251 Posted March 13, 2002 Author Share Posted March 13, 2002 Thanks for the very positive feedback. With any luck at all we'll have a working proto by the end of the month. Using a big ass Hammond SE tranny. Would be very interested in the new 300B types being manufactured. We're using the EH model; Westrex is building the original again, there is also a Sovtek unit and one from China I believe. Any comments on the tube rectifier? We would like to keep it for sexiness sake, but if a solid unit would SOUND better, we'd certainly entertain that as it would make the transformer selection a bit easier. Tone is obviously the bottom line here, and I've always like the sound of a tube rectified Fender over that of a SS recto. But, that's an entirely different animal. Again, Thanks, for the input.... Dave Wendler Instruments Link to comment Share on other sites More sharing options...
JamesPeters Posted March 13, 2002 Share Posted March 13, 2002 I know what you mean about the "cool" factor of having a tube rectifier, and how with class A/B amps you can really hear a difference, but even with class A/B amps there are a few tricks to get the same kind of response without having to resort to a tube rectifier. Now I'm just "talking out my ass" on this (since I've only read from what other more knowlegable guys have said), but supposedly a tube rectifier in a single-ended class A output shouldn't make a difference at all...unless you're talking about an overall lower B+ (which you can accomplish easily enough in the design of the power supply stage to suit your needs). IMO, if you're looking for a bigger, cleaner sound with tighter response, something like a tube rectifier goes against that anyway. It tends to make the attack more "squishy". Anyway it's not supposed to make a difference in single-ended class A. http://petersamps.com Handmade tube guitar amps Link to comment Share on other sites More sharing options...
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