Tube amp for newbye

frarobertooo · 13th March 2008, 03:34 PM

Hello,
I'm frarobertooo and it's the first time I post here and like quite every newbye I won't be probably clear in my request

Please go easy on me!
Well, I have decided to build an amp for my Fender Rhodes with a stereo output of 50 watt or more. I have already some knowledge on electronic but this will be my first real diy project and sure I'd like to keep it simple

So I was looking for an easy, clear, not necessarily cheap schematic with easy to find components. One of my problem is that I really don't know which tubes are regularly manufactured and which are hard to buy.
Could you please help me, also with a simple good link?
Thank you,
frarobertooo

alexg · 14th March 2008, 12:01 AM

Browse the internet tube stores like tubedepot.com and tubestore.com, anything that they sell will be mostly in current production.

A 50 watt per channel project based on vacuum tubes/valves will not be very simple.

If you can live with an 8 watt per channel output, search for Mikael Abdellah's SE KT88 schematic on this forum, that project is quite simple to execute. If you decide to build this amp, search for porkchop's post on his build of this amp, it is very informative and will help you with the project.

This project was my first vacuum tube/valve project.

Psychobiker · 14th March 2008, 12:13 AM

If you're prepared to invest a little, look at the Boozhound amp on www.boozhoundlabs.com

I've dropped >$350 on quality iron, NOS valves....so you can make a REALLY good sounding amp out of it, esp with NOS 12/6SN7

frarobertooo · 15th March 2008, 12:12 PM

Thank you for the answers!
In the last month I have surfed the web but I could'nt find a 50W DIY tube amp kit and my post was much like a last hope query

Now I'm pondering to build a solid state final amp (gaincone ones? Lynx v3.0?) with a tube preamp... is this total weird? I mean, in this way I should have some of the tube audio characteristics with the solid state power.

Psychobiker · 15th March 2008, 11:11 PM

How efficient are your speakers?

90dB/w....

90dB in a small room is freaking noisy. that takes 1W

Jeb-D. · 15th March 2008, 11:19 PM

Quote:

Now I'm pondering to build a solid state final amp (gaincone ones? Lynx v3.0?) with a tube preamp... is this total weird? I mean, in this way I should have some of the tube audio characteristics with the solid state power.

That's not totally weird. Plenty of people have gone that route.

john65b · 16th March 2008, 12:17 AM

First build?

Chipamp.com gainclone. Then a 12B4 Tube preamp, or a JFET BOZ.

basstard · 16th March 2008, 01:30 PM

I know **** about these keyboards [or whatever they are

] but do they have two channels for real?

I saw keyboards connected to guitar/bass amps which are mono,,,

frarobertooo · 18th March 2008, 04:30 PM

Thank you basstard (nice nick

Yes my Rhodes is mono... I'm a little bit confused but I'm slowly undestand what I need.

In the meantime I have found Schematics Heaven and throroughly surfed it. As usuall I have another lil' question:
In quite every schematic it isn't specified the transformer data: how can I determinate which is the right one? In example: In the Marshall 1987 Lead 50W there are 3 transformer but I have no clue of their technical data.

I know I know, I'm the newbye epitome but I really don't like to post several times in a forum with lots of questions...

basstard · 18th March 2008, 06:53 PM

ok, so you can go mono and get no prob mate,,,
I don't know the frequencies these things generate but I'd say you'd better go for a bass amp. A bass can generate from say 20-30Hz up to 8-10KHz so if you get a decent cab that covers the whole range you can get covered almost all of the frequencies you need.
A guitar can generate frequencies from say 160-200Hz up to 10kHz so if you need lower freqs you're not sure to get them with a guitar amp,,,
Or else you could use a guitar amp and modify it to get more lows,,, depends on what you like best really.

In the specific schematic you posted I can only see the 6.3v indicated [that's for the filaments]. What I normally do, is see what voltage is indicated on the schematic just after the transformer and then I buy an adequate transformer that can keep also with the current drawn by the circuit.
This is what I do, maybe there's a more scientific way I don't know of.

If you need to be pointed to some transformer seller/manufacturer in italy just tell me.

13th March 2008, 03:34 PM	#1
frarobertooo diyAudio Member Join Date: Mar 2008	Tube amp for newbye Hello, I'm frarobertooo and it's the first time I post here and like quite every newbye I won't be probably clear in my request Please go easy on me! Well, I have decided to build an amp for my Fender Rhodes with a stereo output of 50 watt or more. I have already some knowledge on electronic but this will be my first real diy project and sure I'd like to keep it simple So I was looking for an easy, clear, not necessarily cheap schematic with easy to find components. One of my problem is that I really don't know which tubes are regularly manufactured and which are hard to buy. Could you please help me, also with a simple good link? Thank you, frarobertooo

16th March 2008, 12:17 AM	#7
john65b diyAudio Member Join Date: Jan 2005 Location: Chicago	First build? Chipamp.com gainclone. Then a 12B4 Tube preamp, or a JFET BOZ. __________________ "I speak Spanish to God, Italian to Women, French to Men, and German to my Horse" - Charles V

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14th March 2008, 12:01 AM	#2
alexg diyAudio Member Join Date: Jan 2005 Location: Philippines	Browse the internet tube stores like tubedepot.com and tubestore.com, anything that they sell will be mostly in current production. A 50 watt per channel project based on vacuum tubes/valves will not be very simple. If you can live with an 8 watt per channel output, search for Mikael Abdellah's SE KT88 schematic on this forum, that project is quite simple to execute. If you decide to build this amp, search for porkchop's post on his build of this amp, it is very informative and will help you with the project. This project was my first vacuum tube/valve project.

14th March 2008, 12:13 AM	#3
Psychobiker diyAudio Member Join Date: Jul 2005 Location: Montréal QC	If you're prepared to invest a little, look at the Boozhound amp on www.boozhoundlabs.com I've dropped >$350 on quality iron, NOS valves....so you can make a REALLY good sounding amp out of it, esp with NOS 12/6SN7

15th March 2008, 12:12 PM	#4
frarobertooo diyAudio Member Join Date: Mar 2008	Thank you for the answers! In the last month I have surfed the web but I could'nt find a 50W DIY tube amp kit and my post was much like a last hope query Now I'm pondering to build a solid state final amp (gaincone ones? Lynx v3.0?) with a tube preamp... is this total weird? I mean, in this way I should have some of the tube audio characteristics with the solid state power.

15th March 2008, 11:11 PM	#5
Psychobiker diyAudio Member Join Date: Jul 2005 Location: Montréal QC	How efficient are your speakers? 90dB/w.... 90dB in a small room is freaking noisy. that takes 1W

16th March 2008, 01:30 PM	#8
basstard diyAudio Member Join Date: Jan 2008	I know **** about these keyboards [or whatever they are ] but do they have two channels for real? I saw keyboards connected to guitar/bass amps which are mono,,,

18th March 2008, 04:30 PM	#9
frarobertooo diyAudio Member Join Date: Mar 2008	Thank you basstard (nice nick Yes my Rhodes is mono... I'm a little bit confused but I'm slowly undestand what I need. In the meantime I have found Schematics Heaven and throroughly surfed it. As usuall I have another lil' question: In quite every schematic it isn't specified the transformer data: how can I determinate which is the right one? In example: In the Marshall 1987 Lead 50W there are 3 transformer but I have no clue of their technical data. I know I know, I'm the newbye epitome but I really don't like to post several times in a forum with lots of questions...

18th March 2008, 06:53 PM	#10
basstard diyAudio Member Join Date: Jan 2008	ok, so you can go mono and get no prob mate,,, I don't know the frequencies these things generate but I'd say you'd better go for a bass amp. A bass can generate from say 20-30Hz up to 8-10KHz so if you get a decent cab that covers the whole range you can get covered almost all of the frequencies you need. A guitar can generate frequencies from say 160-200Hz up to 10kHz so if you need lower freqs you're not sure to get them with a guitar amp,,, Or else you could use a guitar amp and modify it to get more lows,,, depends on what you like best really. In the specific schematic you posted I can only see the 6.3v indicated [that's for the filaments]. What I normally do, is see what voltage is indicated on the schematic just after the transformer and then I buy an adequate transformer that can keep also with the current drawn by the circuit. This is what I do, maybe there's a more scientific way I don't know of. If you need to be pointed to some transformer seller/manufacturer in italy just tell me.

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