Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Instruments and Amps Everything that makes music, Especially including instrument amps.

OTL amps for guitar duty
OTL amps for guitar duty
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Closed Thread
 
Thread Tools Search this Thread
Old 22nd February 2019, 08:06 PM   #191
atmasphere is offline atmasphere  United States
diyAudio Member
 
atmasphere's Avatar
 
Join Date: May 2007
Quote:
Originally Posted by 45 View Post
Rather simplistic assumption. From my past experience you will have interference in high midrange and treble range for sure.
The only full range driver line array that works well is that one using 4" cones MAX size. 5" is already too big! And it has to be rather high to approximate a cylindrical line source. In your 4x8" cones emission lobes will develop.
Moreover its an array so NO way of getting a reasonably sized and/or portable amplifier. Totally unpractical. Only usable if never moves otherwise it's just for museum display.
I am curious to see where do you put the amplifier then. I doubt you can make a reasonable combo amp.
No assumptions- I've had it working and know what it does for over 18 years. It works fine. I've heard it in a number of clubs in Minneapolis. Its nice because it projects so well and you don't have to go deaf on stage while its doing it.

Quote:
Without the weight and cost? You cannot make such general statements sorry. You just wrote that for the 50W amp amp you made an array of 4x8" cones. + head. That is heavier than a 50W combo amp with its OTP and a single driver. No question.
Without any knowledge of the actual amp this is a silly comment. It weighs less than 50 watt combos and that was my goal. I shaved off about 15 pounds. When you're hauling that stuff in and out of bars, up and down stairs, that sort of thing makes a difference.


Quote:

You missed my point. You have been raving about the transparent sound of OTL amps and then you use a cheap interstage transformer that is typically worse than an output transformer of the same price range! You confuse transformer saturation and power stage clipping. One doe not imply the other.
You didn't have a point other than to troll. I didn't miss that.

Clearly as well you have no idea what you're talking about. No experience with the way the transformer was used, no idea of the specs of the transformer... yet you go off as if you know everything about this project and there's no way you can.



Quote:
You might need to replace the speakers too....besides tubes in OTL amps, as used in guitar world, have surely shorter life than typical pentodes. So the long term cost quite higher.
Triode power tubes typically have a 10,000 hour service life- about 5x longer (we warrant them for a year) than power pentodes. If the amps were damaging speakers I would not be in business right now... Sheesh...


Quote:
2x10" its not small. For a 50W amp might be fine but a 10-20W amp? Surely not.
If OTL guitar amps had something more to offer or were more convenient be certain that you would not be alone....doing it for fun is one thing but it ends there.
I'm not alone. This thread is years old and I didn't start it. It only came to life recently when you started trolling it.


OTL amps are fun, that's true. And it has ended there so far. I've seen enough OTL guitar amps at shows to know I'm not the only one.

The amp works fine regardless of any of your remonstrations.
 
Old 22nd February 2019, 10:25 PM   #192
Tubelab_com is online now Tubelab_com  United States
diyAudio Member
 
Tubelab_com's Avatar
 
Join Date: Jul 2005
Location: West Virginia panhandle
Quote:
No you have no idea of what a guitar amp should be
One man's awesome guitar amp is another's box full of noise. There is no one size fits all, although there are some "a few sizes fit a lot" (Fender, Marshall Vox clones).

I have made guitar amps from all sorts of non traditional things from old TV sets to Tiger series solid state amps to traditional FMV clones. I am one to seek out bargains for use in my endeavors and a defunct K-Mart store netted me a trunk load of car stereo speakers some time in the late 90's.

During this time my daughter played in the high school band and her friends spent a lot of time at our house annoying our neighbors with all sorts of musical weaponry. We had a 10 X 18 foot room in the back of the house with a full drum cage, a Roland JV1000, a couple of Strats, a Les Paul, and a cheap bass of some sort. I still have the JV, some of the drums and the Les Paul.

I had built several guitar amps using those car stereo speakers, and within reason they sounded pretty good. They were all SE designs from 4 to 15 watts loosely based on the Fender Champ. Many went to her friends, but there was this Ugly Duckling that nobody wanted. It was electrically similar to the rest, but had nice JBL car speakers that I had removed from my car before trading it in. They were just too clean, and it didn't ROCK, so it wound up doing duty on the JV1000.

One of my daughter's friends gets a new guitar for Christmas and brings it over. He plugs it into Ugly, and magic happened. Ugly didn't rock but she sang sweetly when fed from an ES-335. He wound up taking Ugly home, and eventually off to college, and I never saw her again. There IS a player for every amp....well most every amp.

I have a 100 watt monster in the corner. It is a Chinese clone of a Mesa Triple Rectifier. Twenty Seven kinds of LOUD, but rather lame when turned down to basement friendly volume levels, so it hasn't been turned on in over a year.

I have a little DIY amp that evolved from something I built for the HBAC. It makes about 4 watts when everything is dimed and you wail on it, 2 to 3 watts clean. It cost about $40 at the time of build. The input tube is a bootstrap loaded pentode whose gain can be adjusted from about 20X to over 1000X before microphonics get out of hand. The amp can be adjusted so that saturation comes in the input, tone stack buffer, output, or all 3 stages for a wide variety of tones. This is the only amp I have used for the past 2 years, except for when I just plug my guitar straight into the USB sound module and use an amp sim. I grew up in Florida and learned guitar with 60's surf music, and the sim does a nice job on that slippery reverb sound.

After thinking about this and what Printer 2 said, maybe 10 watts IS too much. a watt or two is probably about right, so lets see what can be squeezed from some small tubes.
Attached Images
File Type: jpg Chassis_1_x.jpg (601.0 KB, 60 views)
File Type: jpg Chassis_3_x.jpg (520.5 KB, 58 views)
__________________
Tubelab, it's 5 year mission. To explore strange new tubes, to seek out new circuits and topologies, to boldly go where no tube has gone before......
 
Old 22nd February 2019, 10:54 PM   #193
45 is offline 45  Italy
diyAudio Member
 
45's Avatar
 
Join Date: Dec 2008
Location: UK
George, everyone can have his opinion and do what he likes. So, as I said, if one wants to do it for fun there is nothing wrong with it and also enjoy it. But that's it.
 
Old 23rd February 2019, 12:42 AM   #194
Tubelab_com is online now Tubelab_com  United States
diyAudio Member
 
Tubelab_com's Avatar
 
Join Date: Jul 2005
Location: West Virginia panhandle
Quote:
everyone can have his opinion and do what he likes.
And that opinion is likely to change over time. In the 70's I actually owned, and liked a Kustom K-200, and liked it, therefore I traced out its schematic and made myself and some friends a clone or three, then sold the original. It turned out that the circuit came right out of the RCA transistor manual, a fact that Heathkit and others also exploited. The Kustom did have two identical RCA power amps wired in parallel, and therefore made more power than the other two, and would deal with a 4 ohm load. Would I want one today? No, nor would too many others.

Quote:
if one wants to do it for fun there is nothing wrong with it and also enjoy it.
I am not aware that anyone involved in this thread is actively making guitar amps for commercial sale, and I have probably sold more guitar amps than Ralph has over the years if you count all the stuff I made and sold back when I really didn't know what I was doing. In those days most of my sales were by word of mouth, or rather sound of amp. There was this little school near where I grew up called the University of Miami. The Olson Electronics store where I worked for a couple of years called it the University of Money.
__________________
Tubelab, it's 5 year mission. To explore strange new tubes, to seek out new circuits and topologies, to boldly go where no tube has gone before......
 
Old 23rd February 2019, 03:01 AM   #195
Printer2 is offline Printer2  Canada
diyAudio Member
 
Join Date: Apr 2010
Quote:
Originally Posted by Tubelab_com View Post
After thinking about this and what Printer 2 said, maybe 10 watts IS too much. a watt or two is probably about right, so lets see what can be squeezed from some small tubes.
Depends on ones situation. If you want a squeaky clean with an inefficient 8" speaker then maybe 10W would be enough, or a 100 dB efficient 12" playing distorted may find you with a Loud 1W amp. That is home messing around not in a band mix. I had a guy over at my place interested in buying my G&L Tele and he asked if I had an amp to play through. Said I had a few so I pulled out four, played through a Fender Frontman, a Tweed/Blackface 6K6GT Champ, a 12AB5 Bassman with a 12AU6 first stage. He also brought his Fender Deville as he knew the sound of it. The guy was a decent player, it was no hardship him trying the guitar through each amp. He had fun with each also, each being different.

The 6K6 with an old 10" hifi console stereo speaker was loud enough. He actually played the 12AU5 Bassman quieter but I have a master volume on it. Would really have like him cranking that one with its Fender 12" speaker in it, it is a band friendly amp. This speaker would probably do well enough for me with a 1W amp. Or one of the Yamaha's I have, great sounding speakers but they do like a bigger cabinet.

I did find a 25BQ6 although I don't know the health. I could get a pair for $20, not sure if I am all that interested. I doubt there will be a OMG difference as compared to a OT version. Or within the power range of the OTL, could the transformer version sound as transparent with judicial NFB and run in Class A dissipating a tone of power but biased to only put out a watt or so? Well, maybe a little more interested now.
 
Old 23rd February 2019, 09:40 AM   #196
45 is offline 45  Italy
diyAudio Member
 
45's Avatar
 
Join Date: Dec 2008
Location: UK
Quote:
Originally Posted by Tubelab_com View Post
I am not aware that anyone involved in this thread is actively making guitar amps for commercial sale,
I have developed the 10W PCL86 exactly for that. It's not just an experiment. I am not the seller though. In return I will get some PSU and OTP transformers wound (my design) for my personal use.
I think the board with all electronic parts, transformers (and optionally Jensen driver 12" ceramic driver) will be available soon both as a kit and finished product.
The one I have been playing with uses the Eminence with Alnico magnet and has been tuned to be used mainly for jazz. Charming warm sound, rich but not fat. High definition, very good attack without being aggressive.
with the Jensen it is still good amp for jazz. Not refined as with the Eminence but butter with overdrive. Last but not least the Jensen is about 2 dB more efficient which is not a bad thing for 10W amp.

Last edited by 45; 23rd February 2019 at 09:56 AM.
 
Old 23rd February 2019, 01:05 PM   #197
Tubelab_com is online now Tubelab_com  United States
diyAudio Member
 
Tubelab_com's Avatar
 
Join Date: Jul 2005
Location: West Virginia panhandle
Quote:
I have developed the 10W PCL86 exactly for that.
I don't know the situation in the UK or Europe, but here you market drops to near zero if the amp doesn't use tubes that are available at a guitar / music store. This was the case even in the 90's, hence my "for sale" amp's all used the same tubes from the "list of 10" tubes found ad Sam Ash, the Guitar Center, or other store.

I keep wondering if it makes sense to offer my little 4 tube amp (it used cheap oddball tubes) in kit form for something like $150 US, but have never done it. There are too many cheap Chinese tube amps out there in the under $200 range. Some are not "real tube" amps, just a 12AX7 driving a chip amp, but the average guitar player doesn't know that.

Quote:
Depends on ones situation.
I don't play too much any more, arthritis and nerve damage has taken much of my ability and my left hand goes numb after 15 minutes or so of playing.

I play the 4 watt amp through a DIY cabinet that I made to use as test speakers. I have a pair and each cabinet has two 6 inch 91 dB "pro audio" drivers. They are not guitar speakers, but can be blasted with 100+ watts without damage. Even with that setup, the little 4 watt amp gets plenty loud when cranked. I can only do that when nobody else is home, and the neighbors hear it even though I'm underground in a basement.

Quote:
25BQ6 although I don't know the health. I could get a pair for $20, not sure if I am all that interested.
The 25BQ6 is on the dollar list at ESRC. I'm guessing that you could get more than 2 in a box that ships for less than $20 to Canada.

The 6BQ6 tube is where I started in the 60's. They were as common as dirt in the county trash dump, and trust me there was plenty of dirt there too. Wire a plate cap to pin 3 of your tube socket, and they fit into a 6V6 - 6L6....socket. The rest of the pins match. I made several "Champs" in my pre-teen years with 6BQ6's. At the time I didn't understand why the bigger 6DQ6 (same pinout) wasn't louder, and often glowed red, but I was a dumb kid that didn't understand things like impedance, or bias.

There are two kinds of 'BQ6's. The BQ6GT and the BQ6GA. They have the same internals, but the GA version has a bigger plate. Unless space is an issue, you want the GA version.

Quote:
could the transformer version sound as transparent....maybe a little more interested now.
This thread has awakened my curiosity as well.
__________________
Tubelab, it's 5 year mission. To explore strange new tubes, to seek out new circuits and topologies, to boldly go where no tube has gone before......
 
Old 23rd February 2019, 03:24 PM   #198
Printer2 is offline Printer2  Canada
diyAudio Member
 
Join Date: Apr 2010
Quote:
Originally Posted by Tubelab_com View Post
The 25BQ6 is on the dollar list at ESRC. I'm guessing that you could get more than 2 in a box that ships for less than $20 to Canada.

Dollar list says minimum order of ten. Shipping usually starts around $13-15 US from most US sellers, no idea what they would want for shipping ten but it doesn't hurt to ask. The problem is, if I am ordering might as well what else they have in stock? could easily go down a rabbit hole. Like maybe a 6CD6GA just for fun.
 
Old 23rd February 2019, 06:47 PM   #199
45 is offline 45  Italy
diyAudio Member
 
45's Avatar
 
Join Date: Dec 2008
Location: UK
Quote:
Originally Posted by Tubelab_com View Post
I don't know the situation in the UK or Europe, but here you market drops to near zero if the amp doesn't use tubes that are available at a guitar / music store. This was the case even in the 90's, hence my "for sale" amp's all used the same tubes from the "list of 10" tubes found ad Sam Ash, the Guitar Center, or other store.
It's the same generally speaking however this is not a large production and he has a very good stock. He can sell both the amp and the kit with a replacement pair of PCL86's for little more.
He has already made another PCL86 amp, 25-30 amps I believe, about 10 years ago for a guitar manufacturer with the same formula. Apparently no one has complained, yet....
He has sold about 50 HiFi amps both finished and in kit using a single PCL86 SE in triode mode. In that case without replacement tubes.
I am confident it will sell because of the sound. It has been developed especially letting professional guitarists play with it and listening to their feedback. Apart from personal taste there things that everyone wants. Personal taste can be easily satisfied with one or more pedals I think.
So in the end if the amp is really appealing the fact the the power tubes are no more in production, but still available in good numbers, won't stop them from buying, I think. It's not expensive at all looking at what the market offers....

Last edited by 45; 23rd February 2019 at 06:57 PM.
 
Old 23rd February 2019, 07:25 PM   #200
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: SW Florida
OTL amps for guitar duty
45 - one of your posts has been deleted for reasons of trolling and disrespect.
Please keep the tone respectful, or you will be put on mute.
 

Closed Thread


OTL amps for guitar dutyHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
OTL guitar amp... M Gregg Instruments and Amps 6 24th May 2017 09:04 AM
IS there any OTL pre amps out there? djn Tubes / Valves 36 15th December 2010 08:37 PM
Anyone out there try a SEPP OTL guitar amp?? aletheian Instruments and Amps 10 14th October 2005 03:05 AM
heavy duty valve amps.... for PA use....? jc808 Tubes / Valves 29 1st January 2005 11:40 PM
[INDIA]Building heavy duty Chasis for Power Amps. ajju Parts 11 20th November 2004 03:55 AM


New To Site? Need Help?

All times are GMT. The time now is 08:48 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki