Well if memory serves me , there have been high voltage FET's for a number of years that you can use in the place of a preamp tube , however it would be very interesting to test one that could be used in place of a power tube indeed.

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Quote from: J M Fahey on May 29, 2010, 10:17:08 PM
I have been making amplifiers for 41 years now, and as a "house rule" I have always offered maintenance for *any* of my products, any age, so I regularly meet "oldtimers".
I have always used Siemens (now EPCOS) electrolytics . Much less than 1% has ever appeared vented or with "salt" deposits , none ever burst or bumped.
I have always used around +/-42 supplies, with some variation between +/-38 and +/-45V , depending on output transistor quality, and 50V rated electrolytics, I mention it to show that I had some safety margin, but not that much.
I was not so lucky with 70's and early 80's vintage Tecate and other Mexican electrolytics and early TRec  (¿Taiwan?) ones, although modern generic ones (China/Taiwan/Korea) work well, time will tell the full story.
In a nutshell: I guess that the quality components used by Trace Elliott, plus their classical over rating (63V caps in 42/45V supplies and so on) means they must still be fine.
Anyway, as Enzo said, popping new fresh ones there won't hurt.
Problems, if any, are usually mechanical, meaning cracked or torn legs because of vibration.

I havn't been building amps quite that long lol , however , yes if a customer insist on a cap change by all means I will do a cap job on a amp , after all , it's a easy job and you can make a fair profit on it. lol lol lol lol

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the EC83 is a single triode and the 12AX7 is a dual , the same as the ECC83 .To answer your question no they are not the same

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put a O-scope on it brother , that's what the circuit does , I'm not saying you don't know what your doing , and I'm also Peavey authorized (for 30 years) . however , take those 2 diodes out of the circuit and bridge the circuit and you tell me what they do lol lol lol I charge $65 for that mod lol lol lol

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Quote from: rodriki1 on May 30, 2010, 02:20:33 AM
another question.

can i believe that there is in this earth a reliable
model for pentodes that could be used in spice?  :duh

i mean with grid compression and so on??

I personally don't use spice or any other computer sim programs , If I want to design a circuit I do it the old fashoned way I breadboard it lol lol lol.

Quote from: rodriki1 on May 28, 2010, 09:42:06 PM
well Thanks for your answer.

that is the point. WHY there is this preference for the tube amp.

SAG?? COMPRESSION??? LOW FI SOUND??? DIRTY in the sound??

but my question is that amp they used in the test sounds to be carvin sx.

thanks.

that's a very good question , yes I like the sag , however if it has a solid state rectifier it has very little sag lol lol lol . Low FI Sound , brother you really need to play thru a good tube amp, the sound quality is in my opinion 100% better that a solid state amp. Dirty , yea that overdriven tube sound is what every solid state  drive circuit has been trying to get for years lol lol lol Now with all that said what I really like is the warmth of the tube amp , the soild state amps have a fantastic clean , but the drive channels all go way past overdrive into distortion That's why I use a multiple amp setup lol lol lol  Finally , the amp they used wasn't a carvin SX brother.

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Well I have no idea bro , but I will say this , a properly engineered amp weather it be tube or solid state will sound good and  be reliable. Which one sounds best is a personal choice I have heard both types that sound great and I have heard both that sounded bad. I use both tube and soild state amps myself , I personally prefer my tube amps.

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If you like the way it sounds , and it doesn't have any problems , I wouldn't change them , If you do it will change the sound of the amp. Also If the ECC83(12AX7A) isn't bad why do you want to change it?

Quote from: Enzo on May 18, 2010, 07:39:58 PM
The Triumph is all tube, the Mace is solid state but for the power tubes.

The diodes in the Triumph are not clipping diodes, they are noise reduction diodes. They never did any clipping.  Totally different function from those in the Mace.

Yea they are brother follow the circuit , I do amps all day everyday and have done a number of peavey triumph's , yes the mace is a solid state pre-amp and power tube output typically 6L6GC as a matter of fact.

you can try the diode clipping circuit , the peavey Triumph used it , I removed it from mine , but you may like it. I personnally like my overdrive to realy be overdrive not clipping from diodes lol lol lol

Enzo if a tube amp :Tube amps don;t pop at turn on, but they sure as hell pop at turn off.  Very common

then ya better replace some filter caps , or it couls possible be a bad output transformer

I was going to give ya"ll some solutions to this problem but  J M Fahey  is dead on the soultion to the problem lol lol lol

first thanks for posting the schematics , those are very good circuits. Now for the The tube amp tone.

      That tube tone (compression, and everything else ) is acommplished as a effect of the entire system not just a single component or group of components. the best compression I have heard myself was from a old Marshall JCM 800 2204 if memory serves me, but if you check out just about any vintage tube amp most components are well out of the 20% tolerance , yes sir 20% , that is also another one of the factors that give ya that tube mojo lol . Then you have the xformers which greatly alter tone as far as that goes experiment with some simple inductors in these Solid Stae circuits it will surprise you the tone you can get out of them. As fair as the filtration goes guys it's really pretty simple in a tube amp there is far more filtration goin on in solid state amps , however with that said yep that influence's the tone too lol lol . as for the vintage cabs I'm sorry folks , but a cab made out of pressed wood with the same dimensions and with a good quality guitar speaker(driver) will give ya just as good tone as that old vintage cab.

          Now , as for the tube amp emulation , yes there are some out there that get fairly close , close enough , most people don't ave a clue as to the difference in tone. However , I'm sorry guys if you what it to sound like a Marshall or any other tube amp , buy that amp , no emulator is going to sound exaclty like that amp.



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                                                     Jack

for the different voltages build a voltage multiplier, I would use 12AX7 tubes . ANY TUBE will operate correctly down to 90V if biased correctly.

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If you really like this amp , and don't feel that you can replace this cap( no part goes out repeatedly without there being another problem) then have the guy replace it( I nave ran a shop for many many years, if a customer ask I will tell them whatever they want to know). Also make sure he shows you what cap it is , in case you want to replace it yourself. However , this cap has something that is making it go out and if not dealt with  you will eventually have a bigger problem.

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                                                Jack Latham

Cool , I'll check it out  :tu:

Teemuk is dead on , for these transformers for the output transformer use a Hammond P-T1650E (15 watts (that's all you really get from to 6v6's)) for the power transformer use a Fener Champ replacement Xformer #125P1B.022772 . This is just an old 15 watt(if bias hot and pushed real hard 16-18 watt) 6V6 Valco amp , they are ok if you like thee Fender tones.