Truth (? ) about tubes

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Truth (? ) about tubes

Postby Polsky » Thu May 04, 2017 5:10 am

Hi Everybody :D
Past few days I had email conversation with our friend from Denmark Kell :D . He had a problem with switching between channels in his IRT 30. He did a really nice work with his amp and also did improvement....the most important improvement about IRT amps. He eliminated hiss which is in some cases a nightmare in IRT's. He also did some changes to Phase Inverter tube which for me was a genius move. I'm so impressed with his work and knowledge and another thing is he opened my eyes to real purpose and designation of tubes. As I said many times I'm not professional electronic engineer or technician. I can repair some simple things or exchange tranny or build thousands amp electrical service for a building. But I love to explore sound of guitar amplifier ...a specially Laney amps which I love so much and play Laney for years now. I love to play guitar and from I can remember I was always looking for the best possible sound of any amplifier I owned. Past few weeks I was testing tubes in my amplifiers. I bought a lot of tubes for preamp and power sections. I spent a lot of time reading articles, reviews and opinions. I spent a lot of nights playing and listening to different tubes and I wrote few things about tubes I have been using so far but it was just yesterday when Kell open my eyes and I guess now I understand what tubes really do to sound of ours amp. First of all I thing the sound of our amp ( in criteria of highs , mids and bass ...general sound) is circuit and transformer. Absolutely not a tube. Tube will not add more highs or mids or bass to overal sound . NO . Tube will drive circuit to give its tone. Some tubes doing this better some worst. Tubes are like fuel to engine. If it has more octans engine work with full power , if less octans or fuel is dirty than engine struggle.
So if we want to get the most from our circuit we have to drive it with good tube. On many tube sellers websites you can find information about "EQ" of all preamp tubes which for me is a rubbish. Each circuit got own tone section which is responsible for amount of highs , mids and bass and there is no way that preamp tube will add or reduce amount of these frequencies. No way. It may only change the way circuit will respond to pots adjustment but will not add more highs or mids. Simple example : Laney TT 50 and IRT 60...these two amps use the same output transformers , I believe the same or very similar power transformers and you can use same kind of preamp tubes in all stages , but they sounds totally different. That's because different circuits was build for these amps. TT using 6 tubes in preamp section and have less....actually different gain than IRT with four tubes in preamp section. And sonically they different like white and black so if you want to change the sound of your amp you have to change a circuit ...not just tube. Some tubes taming response of frequencies in some circuits , some tubes emulate circuit for more hot response. It really does not matters what brand you are using. The matter is what type. Some time designers build a circuits and testing it with 12AX7 tubes and than it turn out 12AT7 is better.
Also very popular is statement that Phase Inverter tube does not affect our tone. I don't think so. I believe PI tube is very important. It sending our tone to power section .I noticed lost of dynamics and power with some tubes in PI stage but Kell did a master movement with his Phase Inverter tube. I will not write about what he did 'cos I do not know if he want to share it . It is his score achieved by hard work and knowledge , but thanks to him I understood the purpose of tube. So if you will change your tubes do not expect you wiil change or add lot of frequencies to your sound. You will change the way your circuit will respond. In some cases you will be not able to hear any differences between tubes , and in other your circuit may respond really strange. And again....there is no bad tubes or the best tubes. Different tubes affecting different way your circuit.

Laney IRT60 H[/color][/b]
Laney AOR 5012 Series II combo.
Laney AOR 100MV[/color][/b]
4x12 Cabinet Vintage30 and G1
[color=#BF0000]Laney AOR 2x12 cab.

Marlboro Ultra Light

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Re: Truth (? ) about tubes

Postby tdiers » Mon Feb 26, 2018 5:58 am

Very interesting. 8) 8)
Laney IRT30-112, IRT-Pulse, Mini ST
G&L Tribute Superhawk, Legacy w/ DiMarzio Fast Track Strat Set
Digitech-The Drop; Morley-Tremonti Wah; LPD-68 Deluxe/Kokopelli/ModernClassic; Keeley-Dark Side; BBE-Sonic Maximizer/TwoTimer/MindBender; MXR-Phase 90

User avatarBowerR64
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Re: Truth (? ) about tubes

Postby BowerR64 » Wed Jul 11, 2018 12:51 am

I kinda think voltage is another thing. If you listen to Eddie Vanhalens tone on his first few records its alot more gainy then other tones of that era using the same amps. I think a higher voltage makes the tube glow brighter and the tone is more clean. If you compare the 12AX7 tubes to say a 12AT7 or a 12 AU7 and look at how bright or dim they are the AX7 is more gainy but its the dimmer of all the preamp tubes when you look at all of them side by side.

I think power tubes are the same way, the colder they run the longer they live but the more ratty they sound.

If you search for Tube Hi-fi amps and look at images they are always VERY bright and these amps run so clean and quiet.

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