Vintage Vacuum Tube Audio

I know that the ARF has a section for tube audio but I don't post much there because I know that the main thrust is for radio. However, my main interest is late 50s to mid 60s tube audio. I also like Knight-Kit transistor amplifiers too. So, if you like it too, let's talk!

Don

I was thinking about getting a setup for my room... What would you recommend? Are there any no-no's? I use the aux on my philips 725 for most things... but i was wondering about the performance of these? Should I buy a used one or build myself ?

Hello Don
I was given some years ago a harmon Kardon receiver from the 1950 s there is write up in one of my old audio mag about that set being one of Harmon Kardons first fm receivers it's in working condition and I have not recaped it yet also at my shopo I have repair alot old tube mac amps to.
sincerely Radio Rich

I have the tube amp that Don gave me in the living room. Thanks Again Don!

I like to relax next to it and stare out the window. I need to get it a nice record changer. And some proper speakers. I have a pair but i dont have the tools to make a nice enclosure for them. You would think my mom would not want that thing in the living room but it looks great. It matches the window frames. I plan on getting it a woodgrain record changer.

In my room i have a nice sony that i found in the trash. With some minor repairs its working. I got it a matching turntable on ebay and the speakers are sony too. The speakers were given to me by Dave This is my window duster And the aux is hooked to the computer.

Hi i have a Eico ST-70 and a Meissner AM/FM tuner..I have not recaped the ST-70 yet but the meissner i have it works nice to 18 tubes! Am trying to get a Eico ST-40 near me..: ) They want 300 for it and speakers and turntable ,i only want the amp..Angelo

I just love tube audio, some of you guys know I have a couple of Dynaco ST-70's, Scott 299B, Lafayette LA-250, Heathkit WM-4, Knight Kit (Model # forgotten), Eico stereo integrated amp, another Lafayette tube amp and tuner and my new favorite home made tube amp I listen to daily the "Darling" 3/4 per watt tube amp. Its in my spare bedroom hooked up to a set of KLH speakers and I found a real small Bogen stereo tuner for $1.00. Attached is that setup. The top photo was before I bought the tuner.

Regards,
Sal

Nice amp, Sal! May I see more?
Bill Cahill

Sure thing Bill,
Here is the back and bottom of the amp.

Regards,
Sal

Nice work, Sal! What do you use as pre amp, and, tone circuits?
What are the nos of the tubes you used in power amp, and, what is the wattage output?
Bill Cahill

Thanks Bill,
No preamp is being used, I plug in my MP3 player directly to the amp. I can adjust the tone from the MP3 player settings, when I use the FM tuner there are no tone controls in the path but it sounds just right!

The "power" tubes are 1626's and the middle tube is a 12SL7. The output.... 3/4 of a watt per channel.

Let me tell you, it sounds great, and louder than my ears can take in my spare bedroom. I built 2 almost identical amps as you can see in this photo.

Sal

i have a MAC240 & [2] FISHER 500? all tube don't know if the fisher's work but the mac240 works fine hope to use someday SMITHY

Sal wrote:Thanks Bill,
No preamp is being used, I plug in my MP3 player directly to the amp. I can adjust the tone from the MP3 player settings, when I use the FM tuner there are no tone controls in the path but it sounds just right!

The "power" tubes are 1626's and the middle tube is a 12SL7. The output.... 3/4 of a watt per channel.

Let me tell you, it sounds great, and louder than my ears can take in my spare bedroom. I built 2 almost identical amps as you can see in this photo.

Sal

Sal,

The first time I saw the 1626 was in my dad's Condenser Checker. I got a few off of eBay for a spare. Never seen the tube use in an amplifier. Triode, what kind of OPT did you use? Primary impedance? Neat!

I'm all kinds of into old tube audio equipment. My main system I listen to at home has a Harman-Kardon Award A300 integrated amp, restored, running custom-built speakers I made in my early speaker-building days (about 18 years ago). I've also got a Stromberg-Carlson ASR333 as a backup amp... and a pair of Eico HF22s, just waiting for me to buy (or build- see below!) a good tube preamp to go with them... once that's done, that'll supplant EVERYTHING else in my main system, most likely...

I've also just taken to building tube gear, as one-offs. Just completed two amplifiers, one from scratch, one nearly so:

1) Custom-built amp, into a cute little rack-mount chassis (originally for a PA gate/limiter/compressor unit). Used 7C5 (Loktal version of 6V6) PP outputs, in a modified Magnavox AMP175/8802 hybrid circuit. About 12w/ch. Outstanding bass range for such a small amp! Wound up getting offered $350 for this one... so it has a new home.

2) Highly-modified Magnavox AMP150 chassis... converted from bi-amp (originally one channel of PPP 6V6 for bass and SE 6V6 for highs) to PP stereo 6L6 (using vintage metal-can 6L6Y tubes). Circuit also based on the hybrid Magnavox AMP175/8802 circuit... beefed up with higher voltages on the preamp and output sections. This one sounded even better than expected- like a good Magnavox console amp restoration would sound, but with more bass extension, less background noise and distortion, and about twice the power (around 22w/ch). Funny thing- same guy who bought the 7C5 amp saw this one... he's now the proud owner of this one too!

I've also got a bench-full... whenever I can get a free moment! Just waiting for me to work on them:

-Two Stromberg-Carlson AU35 amps... these were originally built as PA amps. Restoring one for an Audiokarma member, and modifying the other to be a pretty serious stereo integrated amp. These came with two channels with push-pull 5881 outputs (6L6 type), and some hefty output transformers... I'm looking for something like 25-30 watts per channel, using a modified RCA-spec phono stage, a Marantz-7-design line-stage, and a Harman Kardon A250-design output amp. All using Loktal tubes (7F7s and 7F8s), except the outputs (which will probably wind up being either 6L6Y or some 7581s).

- Two Bogen MX60 amps- again, these were originally PA amps... but they have simply MASSIVE output transformers. Originally outfitted with 8417s... I'm planning to convert them over to ultralinear operation with 6146Bs, ala the original Acrosound ultralinear design, with some modernizations (better phase splitter, etc). These should make some butt-kicking 60 watt monoblocks!

- a custom preamp based on the venerable Marantz 7 design, but with upgrades. Better cathode-follower design, deletion of tone controls and other superfluous (IMHO) circuits, better power supply, better caps. Got a whole set of Mullard 12AX7s and 12AT7s for this one... now I just need to actually BUILD the thing!!

- An old Dumont console amp chassis... originally was a mono PPP 6V6 power amp (four 6V6 tubes total), but I've stripped it down... gonna convert it to a stereo PP 6V6 integrated amp, using the output transformers harvested from some old Hammond organ amps (BTW, both organ amps still work- I had modded both of the organ amps with different output transformers to better drive better speakers, and wound up with these two matching transformers left over). This one will be loosely based on the Harman-Kardon Award A300 circuit (I own one of these, and it's a FANTASTIC amp!), but built as a line-stage and power amp only.

- A Curtis-Mathes console-pull receiver chassis and power supply chassis- PP 6BQ5/EL84. Haven't decided what to do with this one yet. Probably will be built into a Magnavox 93XX-topology amp, most likely...

- a Capehart console-pull receiver chassis, using single-ended EL84 outputs. Probably will convert this over to a small integrated amp (the tuner, unfortunately, is no great shakes... but the amp sounds GREAT)...

- A complete scratch build- based on the amp section of the venerable Harman-Kardon A250 integrated amp... to be built as 25 watt monoblock amps. These also use 6L6 outputs... I have a set of 6L6G "coke-bottle" tubes for these. I'm using a NOS set of Olsen output transformers, a pair of military-spec huge square-can power transformers, and a pair of new-production Hammond chassis for these.

- One other from-scratch project... using a pair of (AFAIK) Baldwin organ output transformers, PP 6L6, as a stereo amplifier. This one is going into, of all things, a highly modified plinth from a dead Dual 1229 turntable- what a FANTASTIC piece of walnut! Should look outstanding! Haven't decided what circuit to use- but with the modified Magnavox circuit and the HK circuits working so well for me, it'll probably wind up being one of those...

All I need is time... where have you heard that one before?

Regards,
Gordon.

Time to get more stuff in the Audio Equipment Discussion. Come on guys!!!!

I have a McIntosh C20 pre amp and two Mc 40's that I bought back in 1963. I am afraid to fire them up until I can re-cap them, as they have been idle for so long. They are in great physical shape, no rust. The chrome doesn't look as bright as it used to. Don't use "Pledge" spray wax around the pre-amp gold lettering, on the front panel... lost a few letters there

Charlie