Pictures of your Tube Amplifiers

[SonicSeeker]

[Vluu]

On 4/24/2024 at 5:19 AM, gromush said:

My modified 300B with custom output transformers and vintage tubes (6sn7 and 5u4G) connected to Forte IV

 

How is the sound on this 330b for your speakers?

[derrickdj1]

The OldChen amps sound nice but, the fixed bias is a problem and necessitates opening the amp with power tube changes to readjust the bias due to possible amp damage.

[Shakeydeal]

[John Warren]

Something a bit different.

 

Retiring from full time work, had time to design a little 7591 p-p amp.  Solid state, power supplies for HV and bias suppliers. non-inductive B+, metal film resistors, microphone cable for all small signals. separate circuits for chassis and 0V references, filtered AC input, all metal construction, no sheet metal screws.  Top plate is CNC machined, black anodized, 1/4" Aluminum plate stock.  Bottom section 300 series mirror stainless, CNC formed directly from my CAD files using SolidWorks.  Can use Lundahl or Hammond transformers.  Everything but the output transformers sourced from USA.    The graphic overlays are the same material plastic lenses for eyeglasses are made from (optical polycarbonate).  

 

There's a very cool hifi store a few miles from my place where we gave it a listen for most of the afternoon on a pair of Focals and they'd like to have the amp to show in their listening area.  I'll set up but I'm a wee bit hesitant to become an amplifier manufacturer, could be fun but some hassles to.  I'd have to set up a facility.   Then there's the "how do you compete against the Chinese $800 everything tube amps?"   

 

 

 

 

 

[Shakeydeal]

Nicely done!

 

 

[Tarheel]

Nice work John!  Looks like a McIntosh ML-1C speaker in the corner?

[John Warren]

Thank you gents!

 

1 hour ago, Tarheel said:

 Looks like a McIntosh ML-1C speaker in the corner?

Yes, it is.   I always liked the look of the -1C, the cabinets are old school, 1" thk particle board.  Note the equalizer sitting on the tuner.  Without either the MQ101 or 102 equalizer the ML systems will have poor bass response so, if you buy a buy a pair without the equalizer, you will be unhappy.  

[Dave1291]

On 6/5/2024 at 6:27 AM, John Warren said:

Then there's the "how do you compete against the Chinese $800 everything tube amps?" 

Wait, did I miss something?  You're retired, there's zero competition now.  lol  EVERYthing today is pay to play.  You throw it into the mix and people line up, take it at your own pace.  YOU control your destiny.  Chill..  Zero clue what it sounds like tbh but it's a beautiful build.  It HAS to sound fantastic so just sit back and pace yourself.  Just my opinion and you know what opinions are like.  Looks amazing though! 

[John Warren]

14 hours ago, Dave1291 said:

Wait, did I miss something?  You're retired, there's zero competition now.  lol  EVERYthing today is pay to play.  You throw it into the mix and people line up, take it at your own pace.  YOU control your destiny.  Chill..  Zero clue what it sounds like tbh but it's a beautiful build.  It HAS to sound fantastic so just sit back and pace yourself.  Just my opinion and you know what opinions are like.  Looks amazing though! 

Brilliant!  

[Shakeydeal]

@Dave1291 is right. You won't be competing against chi-fi crap. Those buyers aren't your target demographic. People who want good quality at an honest price are the ones who will seek you out. And you have the convenience of building for whomever you choose.

[Dave1291]

@John Warren btw how much they goin for?  😂   😂   💪

[opnly bafld]

9 hours ago, Shakeydeal said:

chi-fi crap.

 

 

Speaking of ^ here is a new to me used Oldchen 300B amplifier; considering what the tubes that came with it are worth the amplifier itself was almost free. I don't like all the white goo everywhere underneath, but it seems to be well built, the transformers are good size (might be crap, but at least not tiny crap). The 300Bs are DC heated and have a neat way of fine tuning with a multi turn pot to eliminate what little hum there is.

It is my first DHT amplifier and although I was kind of wanting a US made 2A3 the price of this amp made it hard to pass up.

 

After having it for a week I'm very happy with the sound and the purchase.

 

 

 

 

[opnly bafld]

Here is another recent budget purchase with some new caps and resistors, an IEC, fuse, and power switch added. Binding posts installed to make it easier to rotate into my systems and a wood bottom to keep me from shocking myself.

This single ended 6BQ5 (6P14P-EV) pentode is just a lot of fun to listen to, it was designed by Magnavox with a bass boost by means of the feedback circuit and the coupling cap*. Have not tried it on more full range speakers, but it sounds great with a pair of Fostex wideband drivers.

 

 

*Edit - I increased the size of the coupling caps to flatten out the "bass boost".

 

 

[John Warren]

1 hour ago, Dave1291 said:

@John Warren btw how much they goin for?  😂   😂   💪

Info here:  North Reading Engineering

[John Warren]

10 hours ago, Shakeydeal said:

@Dave1291 is right. You won't be competing against chi-fi crap. Those buyers aren't your target demographic. People who want good quality at an honest price are the ones who will seek you out. And you have the convenience of building for whomever you choose.

 

Truth and good advice, thank you.

 

[kippy]

My MC-225 on HF duty with my Jubilee speakers. Sweet, round, musical sound. A tiny bit noisy and perhaps a bit less detailed in comparison to my First Watt J2 but a really wonderful piece of engineering from the 1960s. Velvety sweetness when used with the horns.

[opnly bafld]

On 6/4/2024 at 12:27 AM, derrickdj1 said:

The OldChen amps sound nice but, the fixed bias is a problem and necessitates opening the amp with power tube changes to readjust the bias due to possible amp damage.

 

Thankfully the 300B amplifiers are cathode bias.

[S391]

I recently picked up a new Dynaco ST70 that was built by Kenny Russel at getdynaco dot com.

 

Edited June 26 by S391
add pic

[jcmusic]

Here is my Darling 1626 I just got about a week ago, just spending some time with it. Love the sound it has I am really surprised at how good it is....

I had been looking for a flea powered amp for quite awhile and posted a few WTB adds and finally someone contacted me about this little amp.

 

For those interested here are the details for this amp:

 

I built this little amp about 6 months ago and it's seen about 25 hours of use. You could think of the amp as a JE Labs "Simple 45" except it uses the 1626 output tube (the schematics are virtually identical except for output tubes and naturally different operating points).

The tubes include a 5U4GB rectifier, a pair of 1940's Hytron 1626 power tubes and an RCA JAN Black Plate (graphite coated envelope) 12SL7 driver tube (all tubes were new with the amp and have about 25 hours on them max).

I've really enjoyed this amp in my Den and used it to drive some custom made 94 DB single driver speakers with plenty of volume and dynamics for my listening level. The tube puts out about .75 watts per channel so more efficient speakers will be needed in a larger room. However, I let one of my friends with a pair of Lowther Alerion speakers at around 94 db efficiency listen to it in his larger room and he really liked it. But he already has two of my hand built amps and couldn't really justify buying another one (he has several other tube amps as well) so this one is available to the public at large.

The amp has an overbuilt power supply and is really quiet. I used a seperate filament transformer with center tap to help with hum balance and avoid any coupling noises between windings in the power transformer which I think helped.

Some other details about the amp:

-- NOS USA Made Pyramid Paper in Oil Coupling Capacitors

-- Teflon Jacketed Silver Clad copper for all signal carrying wires.

-- Made in USA new Edcor output transformers

-- Super short signal path, with an attempt to use only the leads on most resistors to minimize the number of solder joints.

-- Lead free Kester 3% silver solder used exclusively

-- Vintage Power transformer that I picked up on Ebay last Summer (spray painted it a hammertone black to match the plinth).

-- A hybrid star ground that uses a short silver clad copper bus bar that is reputed to be quieter than a straight star ground (high currents are kept from commingling with sensative signal circuits).

The amp is point to point wired, although I did build the power supply on a perf-board to conserve space and to better group the power supply grounding node.