What would it cost to build a >8watt tube amp?

[Jonesy_SA]

Hi

 

I was looking at Chinese tube amps based on el34 tubes in the 10watt range and wondered what it would cost to build something locally.

Excluding chassis and using readily available components (that is to say no fancy vintage components) what's a good figure?

Any chance of a price breakdown on an actual build?

 

Cheers

[Guest]

Hi
 
I was looking at Chinese tube amps based on el34 tubes in the 10watt range and wondered what it would cost to build something locally.
Excluding chassis and using readily available components (that is to say no fancy vintage components) what's a good figure?
Any chance of a price breakdown on an actual build?
 
Cheers

You mean to buy the parts and build it yourself, or a custom build?

[Jonesy_SA]

You mean to buy the parts and build it yourself, or a custom build?

Buy the parts based on a reputable circuit and build myself. I'm fine with HV. Would prefer point to point and not a kit.

 

[Jonesy_SA]

I suggested locally on the basis that most DIY audio I come across is from USA. Their prices and availability of parts is different to ours. There might even be a good schematic with BOM for local components.

[Full Range]

31 minutes ago, Jonesy_SA said:

 

Hi

 

I was looking at Chinese tube amps based on el34 tubes in the 10watt range and wondered what it would cost to build something locally.

Excluding chassis and using readily available components (that is to say no fancy vintage components) what's a good figure?

Any chance of a price breakdown on an actual build?

 

Cheers

 

 

Try this site with many DIY design choices to choose from 

 

http://diyaudioprojects.com/Schematics/

[davewantsmoore]

The answer really depends on how much money you would like to spend on capacitors and transformers.... otherwise the biggest cost is the case.

 

Assuming this is a simple SE amp with something like a EC86 cap EL34 (sorry, not an amp guru) ... then I reckon $500 in parts would pull it up.... less if you really wanted to stinge .... and just keep moving the decimal place to the right otherwise 

[mwhouston]

For a SE EL34 amp with choke, power tranni and reasonable OPTs about $800 for parts only. 

[acg]

A top quality opt will cost at least $1k for a pair, some closer to $2k.   I would not bother building a SE tube amp unless you have compatible speakers and at least $3k to $5k to waste on parts,  including the chassis. Just my opinion.   It can be done for much less... but the opt's are both the major expense and the major bottleneck in most designs. 

 

[Mendes]

21 minutes ago, acg said:

A top quality opt will cost at least $1k for a pair, some closer to $2k.   I would not bother building a SE tube amp unless you have compatible speakers and at least $3k to $5k to waste on parts,  including the chassis. Just my opinion.   It can be done for much less... but the opt's are both the major expense and the major bottleneck in most designs. 

 

+1......... do you want cheap or something that sounds great?

 

You get what you pay for......

[PicoWattson]

..and this is at the pointy end of EL34 kits.

 

http://www.ankaudiokits.com/EL34-MonoBlock-C-Core-Power-Tube-Amplifier.html

[Ihearmusic]

Hammond transformers and choke ~ 700.-

Tubes ~ 200.-

components and wiring ~ 150.-

Don't worry about expensive OPT.  I use Hammonds and I get a nice flat response from 15Hz to 30kHz within 1db from my 300 B SET.

And do not listen to any nay Sayers. They don't walk in you shoes. 

[Happy]

5 minutes ago, Ihearmusic said:

Hammond transformers and choke ~ 700.-

Tubes ~ 200.-

components and wiring ~ 150.-

Don't worry about expensive OPT.  I use Hammonds and I get a nice flat response from 15Hz to 30kHz within 1db from my 300 B SET.

And do not listen to any nay Sayers. They don't walk in you shoes. 

Would love to see some piccies  

[acg]

33 minutes ago, Ihearmusic said:

 

Don't worry about expensive OPT.  I use Hammonds and I get a nice flat response from 15Hz to 30kHz within 1db from my 300 B SET.

 

At what power do you have a nice flat frequency response from your OPT's?  I'm not saying that your Hammonds are or not rolled off, because Hammonds are basically decent transformers, and because I do not know how you are using them or loading them.  Your specific scenario does not really matter for my point though, which is that a lot of transformers are not spec'd at full output power because that frequency response does not look as good as the response from that transformer while it is idling away at a small fraction of its potential.  The only really useful frequency response is that at full power, say 1% or 5% distortion.  To get good measured performance at full power the opt has to use a lot of iron and some good winding techniques all of which cost money.  

 

I think the Lundahl OPT's are really difficult to beat.  They are uniquely and ingeniously made, flexible in their application, and seem to be honest in their specifications.  Their distortion and frequency response measurements are in general almost impossible to beat, especially when price is included in the equation.

[davewantsmoore]

All this really depends a whole lot on the speaker ... and makes generalisations really hard (or misleading).

 

How often are we really going above ~1w / Is bandwidth really needed below ~40Hz  ('cos we crossover to subwoofer around ~80Hz?) ... etc. etc.

 

Performance depends more on how you use it ... Same as performance depends more on how well the circuit is tweaked/matched/adjusted than ultimate part 'quality' in many situations.

[Ihearmusic]

2 hours ago, Happy said:

Would love to see some piccies  

By the way, the transformers for my 300B are a bit more expencive then what I quoted above. Mine are mono blocks.

work for the enclousers are still in progress but here is a pic of the test bed for one channel.

[Ihearmusic]

1 hour ago, acg said:

At what power do you have a nice flat frequency response from your OPT's?  I'm not saying that your Hammonds are or not rolled off, because Hammonds are basically decent transformers, and because I do not know how you are using them or loading them.  Your specific scenario does not really matter for my point though, which is that a lot of transformers are not spec'd at full output power because that frequency response does not look as good as the response from that transformer while it is idling away at a small fraction of its potential.  The only really useful frequency response is that at full power, say 1% or 5% distortion.  To get good measured performance at full power the opt has to use a lot of iron and some good winding techniques all of which cost money.  

 

I think the Lundahl OPT's are really difficult to beat.  They are uniquely and ingeniously made, flexible in their application, and seem to be honest in their specifications.  Their distortion and frequency response measurements are in general almost impossible to beat, especially when price is included in the equation.

Measured at 1w into resistive 8 ohm load.

initial listening tests show no short commings driving my ZU speakers.

My ears have the final say not my test gear.

And yes, one day I would love to get my hands on a pair of Lundahls.

 

[Happy]

9 minutes ago, Ihearmusic said:

By the way, the transformers for my 300B are a bit more expencive then what I quoted above. Mine are mono blocks.

work for the enclousers are still in progress but here is a pic of the test bed for one channel.

I like rudimentary chassis

[davewantsmoore]

28 minutes ago, Happy said:

I like rudimentary chassis

My cats would not survive one afternoon   

[Ihearmusic]

50 minutes ago, davewantsmoore said:

My cats would not survive one afternoon   

Hmmmmm. Might be an expensive solution to the feral cat problem.

Our cat and the dog are ok with it. I just have to make sure I don't leave any part on the floor otherwise the end up in the back yard somewhere.

[Ihearmusic]

Ops

Edited August 26, 2018 by Ihearmusic
Double post

[Jonesy_SA]

I have been looking on RS at transformers. Is there better prices?
I doubt I would use anything less than Hammond quality however are there cheaper alternatives?

I would prefer to keep cost to a minimum and have no preference for design or tube selection so open to suggestions.

[Jonesy_SA]

 
Try this site with many DIY design choices to choose from 
 
http://diyaudioprojects.com/Schematics/

Thanks! I've contemplated copying a circuit from one of the kits as they seem well received.

[davewantsmoore]

6 minutes ago, Jonesy_SA said:

no preference for design or tube selection so open to suggestions

What speaker are you going to drive?

How loud?

[Full Range]

10 minutes ago, davewantsmoore said:

What speaker are you going to drive?

How loud?

 

That is a good question 

As for the 8 W  power rating the OP will need 95db + sensitivity speakers 

[Ihearmusic]

39 minutes ago, Jonesy_SA said:

I have been looking on RS at transformers. Is there better prices?
I doubt I would use anything less than Hammond quality however are there cheaper alternatives?

I would prefer to keep cost to a minimum and have no preference for design or tube selection so open to suggestions.

Edcor transformers would be a contender but the shipping cost will kill that deal.

Check out Evatco, they have specials sometimes on Hammonds.

Mouser deserves a look for Hamonds as well.

China is your best bet for really cheep stuff, shipping is reasonable. But................I don't have to repeat it!

My Black Betty runs on roughly $150.- worth of transformer. (Equals one OPT from hammond) It is low power pp however.

Edited August 26, 2018 by Ihearmusic
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