So I'm sitting in the chat room with a few of youse guys on Tuesday night, clicking away on the laptop and cleaning this little Eico tube amp, basically because I've nothing better to do, and it's something I wanted to get done. Anyways, I get it all spic and span, so I decided to hook up a TT and a test speaker to see if I can get any sound out of it. Powers up, and it took about 10 minutes of fiddling with the buzz control and figuring out the hookups (wasn't labelled), and BINGO! What comes forth I can hardly believe my ears! The sound is so clear, transparent, and pure! I think that I have found the sound I've been looking for! So I hook it up to one of the Ohm E's (mono amp), and I sit back and lose myself in the music. I was so excited I could barely sleep!

Fast forward to yesterday. I thought "well, if that Ohm speaker was that goos, the VOT and a horn should blow my mind!"

Well, it didn't. Had very little bass (and I'm a bass kinda guy :D), but the high notes were incredibly clear, if harsh. Disappointed, I hook the Ohm back up, and it was the same nice sound I heard before, but where's the bass? :confused:

So come on tube guys, help me out. Is my lack of bass due more to the amp, (an Eico HF-12), or because of some other factor?

Here are the amp's specs....

Tim,

The little Eico amp (BTW, thanx for cleaning it for me :) ) won't have as big an output transformer as you can get for a pair of 6BQ5's so some bass is lost there. The bigger reason IMO is that the Altec A7-800 has poor bass response and doesn't work properly anyhow in your listening room because you need to sit 35 feet out in front of these before they phase properly. The Altec bass horn only loads down to 200Hz and then the rear radiation from the driver is recovered with a bass reflex port down to 50Hz in this classic design. In my A-7 commercial system I had to add four 614-A Bass bins, one under each A7 cab to get decent bass from the total system. Each bass bin is equipped with a heavy duty Altec 421-8H series II woofers pumping on 200 watts RMS.

I don't know why the Ohm speaker shows a noticeable deficit of bass with the Eico unless it is an efficiency thing. If the Ohm is happy with a 100 WPC solid state receiver then power is the issue.

I'm glad that you are starting to hear that there is really something to this tube phenomenon that has people like me hooked. I gotta build you an amp soon, and I will as soon as I figure out what I am gonna build. See my post from yesterday in the Tubes section. http://www.audiokarma.org/forums//showthread.php?s=&threadid=1271

Rob

Definitely liking toobz :D

Rhymes with my other fascination ;)

At least now I know why I blew the one woofer in the Ohm E. I think these things are set up for very low wattage....it sings with the Eico, but was overloaded by the Pioneer.

Wait, I guess it doesn't rhyme with "large vintage receivers"!!!!

Yes you have crossed over!! Come back you traitor!!! ;)

LOL Tim your story sounds like mine. Always lived with solid scrape and even have a big ole nice 2001 model H/k 510 AVR that I had been listening to music and DVDs with. About a year or so ago my older brother drops a stock Dynaco ST 70 in my lap and for fun I threw it on the pre outs of the H/K. It was a total jaw dropping experiance. Really caught me off guard so to speak. From that though I saw the light. That is the light of the glowing tube. The audiophile fireplace eh? ;) I have been tweakin that Dynaco ever since and loving it!! Find yourself a 95db or so speaker and watch what happens...

Fisher 500c,500c,500c,500c,500c. I'm gonna pester you till you try one. 35 underrated watts of pure tube power, and in stereo too. wonderful FM tuner and a nice phono stage. and with the 7591 tubes being made new now, there is no reason not to give one a whirl. Besides, it is a receiver and you can never have too many of those. :D

The Rocherster NY antique radio show is this Wednesday, the world's largest. After that I'll consider my next move :)

Certainly congrats on your latest discovery. That for me is what is important, not how we learn or even what but that we continue to explore and learn. While I like tubes, or more precisely the 45 in single-ended configuration I think TOO MUCH is made how we engage ourselves. Tube or SS, multi or single-driver... it's all about the music being served, and the listener delighted.

MikE

Don't feel bad, but you drug me in with you. after being on the board that night, I have to have a tube amp. We will just have to wait and see what I end up with.:D

I have some of those HF-12s and the iron really leaves a lot to be desired and not just the OPT. The power supply is so small and has the 6CA4 so close it that it runs hot as a fire cracker. Not a bad little amp but certainly no great shakes. The same circuit done with better transformers and larger caps would be much better but you get the general idea. Pretty darned good for 12 watts at medium bandwidth!!
And VL is right about that Fisher 500C. They are great. I like the 400 reciever mucho mucho too.