Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Colas LeGrippa on November 04, 2020, 02:45:02 pm
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Hi my friends, I didn t show up since I tried to fix the f....Musique Industrie ( easily translated in english) guitar amplifier brought to me by a musician from Paris. I suspect he tried to fix it himself but he was arguing the amp had had an issue caused by the airplane.....Anyway, after spending over 30 hours trying to hook up all the disconnected wire to the right place in order to make it work, I called my client ( my last one I swear to God) telling him I failed correcting the issues the airplane caused...and finally he came to my place to pick it up. Gee whizz , I can breathe normally now, my nightmare is over.
Now I want to feel the pleasure of building an amplifier with no obligation of result in a given time. I have a PP 6v6 on my bench that sounds great ( copy of Top Hat club deluxe ) but doesn t have the guts I am looking for. I want to mod the preamp for heavy rock tone.
What would you build ?
Thanxx
Colas
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Check out the tremolo TMB at 18watt.com. I built that thing and it is woooooow!!! Hands down the best amp ever! It's an el84 amp, but can easily be done in 6v6
Otoh.. that tone king imperial clone I just finished is awesome too!!!
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Does this match what you have?
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Not the same Club Deluxe
Mine is with paralleled 12ax7 as first tube
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...he was arguing the amp had had an issue caused by the airplane.....
Yeah. The plane was 230V by the entrance door and 120V at the exit door. It's all the plane's fault.
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but doesn t have the guts I am looking for.
if you put a gain pedal/tube screamer, in front, does that move you in the correct direction??
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PRR, I think the main issue was the musician himself...
SHOOTER : yes in the good direction but yet many miles to drive !!!!
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Mine is with paralleled 12ax7
put them in a straight line, fix the DCCF to Merlin's diode version
I can overdrive KT88's with that setup, (notes say 74Vac_rms) out of the DCCF
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Very interesring indeed. The bootstrap version of the CF without the diode yields even more gain. Back to my shop , ll give it a try that s for sure.! But before, I promised an old lady I would repair the chipped concrete on her fundation wall...but I m so anxious to tweak my amp I think I ll cancel her.....
Shooter you re a brother. :icon_biggrin: .
Colas
PS : there are good winners and good loosers.
The problem is when you get a bad winner.
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The bootstrap version of the CF without the diode yields even more gain.
No matter how you roll it, a CF will always have a gain of slightly less than one. Been that way since Noah. :icon_biggrin:
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Sluckey , didn t know you were that old. If you have known Noah, you didn t meet Merlin because he says the opposite...But no prob., Colas will test both and get back to you. :icon_biggrin:
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Merlin says, "The cathode follower operates with 100% negative (voltage) feedback, which makes it exceptionally linear and minimises the output resistance. The price we pay for this is gain, which is slightly less than unity."
http://www.valvewizard.co.uk/accf.html
Perhaps you misunderstood?
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Shooter you re a brother
:laugh: My family admits it, only I'm; from the other side of the family
PS
do the 'ol ladies work, they really like 60yr old buns :icon_biggrin:
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sluckey,
He's referring to this version: (from the bottom of this page: http://www.valvewizard.co.uk/dccf.html (http://www.valvewizard.co.uk/dccf.html))
"Because the cathode follower acts as an impedance buffer we can use it to 'bootstrap' the previous stage. This is done by splitting the previous stage's anode resistor into two equal parts and connecting a capacitor from the cathode follower's cathode, to the junction of the two resistors [see right]. The cathode follower then effectively multiplies or bootstraps the value of the lower anode resistor R2, making it look like a constant-current source. This will increase the gain of the previous stage so it becomes almost equal to the mu of the valve! An added bonus is that if you don't use a cathode-bypass capacitor, the gain is still very hgh (about 85-90 with an ECC83). Leaving the cathode unbypassed reduces blocking distortion and reduces 'fizzy' sounding overdrive, giving better crunch. Usually you sacrifice a lot of gain though, but not in this case! So I guess you can have you cake and eat it too...
But, I believe Colas is mistakenly considering the entire coupled circuit to be the CF.
Colas, Merlin is referring to the increase in gain of the previous stage that is coupled to the CF. The term CF stands for the 1 triode where the signal exits at the C, not the whole of the coupled stages.
Noah told me this so it must be true. :icon_biggrin:
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I was just poking at Colas. I believe he knows that. :icon_biggrin:
However, many non-tech people mistakenly think the "previous triode" is also part of the CF just because it's usually (not always) in the same bottle. Same thoughts about a cathodyne.
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This will increase the gain of the previous stage
I was working on a new amp, posted schematic, forgot to add the cap.
when Steve pointed out the mistake n PRR explained why, I went to Merlin's site and found a bunch of cool other stuff :mail1:
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Here's how I set mine up.
I like the use of the terminal strip to create the split load setup and then just jump the cap across to the CF.
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Hahaha ! You re so funny, amigos !!!!
Sluckey, you and I have developped a particular
relationship over the years. When the border is opened, I ll take a motorcycle ride to your country and offer you a beer. (If you pay) :laugh:
I may be dumb sometimes but I fully understand what is a cathode follower.
We used to call CF the entire tube but only the second half is the CF. Schems say it all.
Right about what I am refering to, Silvergun, why are you the only one to understand me ? I d bet you voted for the right president....
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Right about what I am refering to, Silvergun, why are you the only one to understand me ? I d bet you voted for the right president....
Oh yeah, I voted for Reagan!
Killer preamps are a universal language and I usually read your posts, so the fact that I've been messing with this BS CF got me all riled up.
Plus, I was one of those guys who thought the term CF stood for the whole package, so I'm always lookin to help a brother out. :thumbsup:
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Oh yeah, I voted for Reagan!
:l2:
I had just signed my life away for 6 years and all the cool kids said he would get me killed for no reason, So I waited n voted for Him the 2nd time around :icon_biggrin:
while I know there is a gain stage AND a CF stage, I tend to treat them as a "single circuit" sorta like 30 transistors in one cute IC package
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OMFGLOATFGL OMG !!!!!!!
I MADE THE MOD WITH THE( sorry for shouting, I ll cam down now....) with the split load resistor.
WHY DIDN'T YOU TELL ME BEFORE ABOUT IT ?
( ...don t answer why didn t you ask, I am standing here since years asking and asking for high gain tricks !
Deep breathe....haaaaaaaah !
Sluckey, the diode trick not worth a Xxxxxxx. Better chance nex time hey hey !
Thanx buddies ( don t cry Sluckey...) for that awesome mod. Now I got to boost the B+ supply caps in the preamp cause I m getting oscillation. I replaced the TMB by a tone pot connected to the MV.
In there you can find: MOJO caps, Angela paper in oil, orange drops, ceramic disks for tone..
Carbon comp and metal film resistors. I picked up parts in my mixed nuts pot to originally build a deluxe 5E3 which I turned into a Top hat club deluxe and now a "Colas and friends Deluxe"
How's hat ? :icon_biggrin:
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"Colas and friends Deluxe"
How 'bout a CF Deluxe? :icon_biggrin:
:occasion14:
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:l2: :l2: :l2:
:l4: :l4:
I am the cathode and you are my followers !
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Sluckey, the diode trick not worth a Xxxxxxx.
wrong player :icon_biggrin:
at least I helped drag you to the bench, so who followed who :icon_biggrin:
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... Sluckey, you and I have developped a particular
relationship over the years. When the border is opened, I ll take a motorcycle ride to your country and offer you a beer. (If you pay) :laugh: ...
I bet Sluckey will happily buy you a beer! (Right after you hand him the money... :icon_biggrin:)
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Come on down. No need for money. I'll introduce you to ICEHOUSE.
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I know I wouldn t have succeeded without your post on DCCF, Sluckey, I was just returning your poke, amigo. Btw, I didn't try the diode version :laugh: .
Thanks to you all.
I wish you a president who will spread peace, love and respect. On the other side of the border we canadians are following the US election with
great interest. The entire world does it.
Colas
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Hi buddies, I worked all day on my new amp.
I ended up hooking up the CF circuit according to Sluckey's suggestion, with the diode. I first wanted to do it my way ( my wife knows that....) according to Merlin recommendation for max gain but it appeared to be too much fizzy sounding. The diode trick is much more musical and round. I beefed up the CF B+ supply to 47 uF to get rid of the oscillation and everything is stable now. I am planning posting sound clips of the 4 amps I built and that I am currently using, plus a 12AU7 overdrive pedal of my own.
I ll post here the YOUTUBE link when it's done.
Cheers !
Colas
PS: Sluckey now IOU a caisse of beer :icon_biggrin:
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Your wife??? Has she met your girlfriend? :icon_biggrin:
BTW, I have never ever never mentioned diode in this thread.
And I don't know what a "caisse of beer" is but if it's bigger than a thimble I'll drink it with you.
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Right Sluckey, it was Shooter who first mentioned the diode. Tanks to him No prob. we' ll drink all together then, with distance of 6 feet and masks......
Now my girlfriend IS my wife. It s more practical to have both in the same body.
Just like a gain stage and a CF.....
Very long time ago, my boss who was speaking only english used to say: " Jacques, go get a caisse of beer" . He was refering to a pack of 12 or 24 regular bottles. As a matter of fact he was using the french word. Surely would be a pleasure to drink a glass, pint, jar, pitcher...name it , the envelope is not important but the liquid inside ! One of these days after the covid, I ll ride my HD down passed the border to a bar near you.
Cheers !
Colas
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You realize I'm on the gulf coast? I'll treat you to some good local seafood to go with that beer. Bring your wife too. I'd like to ask her some questions. :laugh:
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Gulf Coast ? You re a lucky man !!!! Many tornadoes but warm temperature all year long !
Riding my motorbike till Texas isn't a problem for me . My wife with me ? Nooooooo ! My bike is a one seat bobber Harley D. I modified it on purpose hey hey !
See ya next summer, if the bordet is opened and if the f.....virus is under control.
Cheers.
Colas
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Come on down.
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> Very long time ago, my boss who was speaking only english used to say: " Jacques, go get a caisse of beer"
Very long ago, beer came in glass bottles, with deposit, and were transported in wooden cases, usually 24 bottles to a case.
https://en.wiktionary.org/wiki/caisse From Latin capsa. Case, caisse, who cares?
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after the covid
:l2:
sub-microscopic killer microbes here before humans, will be here well past them, so just take the dirt roads, get a virus-free doc from the internet for $60us and drink a beer
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PRR, yes you re right. As a matter of fact when I was young ( I am still young though...), the father of my best friend was working for Coca Cola. lifting wooden cases full of small glass bottles. He wasn t going to a gym after his day of work I guess....Lately I discovered an empty case made of wood in a basement full of debris. They were really well made and solid.
My mother would give e a coke from time to time I was just loving it.