EICO HF-81 6bq5 Vintage Tube Amplifier Restoration
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- เผยแพร่เมื่อ 10 ก.ย. 2024
- Incredible transformation of an Eico HF-81 vintage tube amplifier from a recycling bin basket of parts to a fully restoresd, fined tuned and absolutely beautifuly looking unit that sounds spectacular.
Wow to have a separate unit to compare is awesome!
It made me happy to see your rework powering horns.
It made me happy to see that you left a comment. If you haven’t, please subscribe, I would really appreciate as it would help the channel immensely.
The HF 81 can power, the clips horns rather easily!
Thank you once again teammate.
Oh how I wish my hands were that steady and nimble. Good job!
@@ginocolaianni46
Thank you very much, teammate!
You made my day!
If you haven’t subscribed please do so I would really appreciate it because it really helps my channel!
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You describe exactly how a good tube amplifier can sound.........And the 6BQ5 ( EL84 nos ) is considerd as the 300B of the poor ............
Modern tube amplifiers ( not all ) often do NOT sound nothing like those....
Ashonishing resurection ...........like a reanimation of a human ....
It was a blessing tohave a working unit as a reference ...
Kind regards
Hello teammate! Thank you so much for watching liking and commenting. I really appreciate it.
It is hard to believe that it is the same unit and it is also hard to believe that can sound so good!
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Yeah, these older 6BQ5 unit did have a really good sound. The last one I've restored for my client was a heathkit A-151. It has ultra linear transformer with a grill tap. It sounded crazy good.
@@SurnaturalM Hello teammate! Thank you very much. I’ll be on the lookout for one of those on eBay.
This one of the best integrated tube amp ever. I hope you will enjoy. I have few eico, 2 HF-60 and the st-70 with the tuner and mpx. The last one is a bit noisy, too much front end gain, but I love it. Your (what I can see) mc250, is also my favourite solid state amplifier. The semi push pull and output transformer have a lot caractère and I that's what I like.
I've rebuild and restored many amplifiers, juke-box, and what you said about the ground is very important, twisting heater wires closely together and putting those near the chassis really affect the hum as well. Nice restoration.
Hello team and thank you very much for watching my video liking, subscribing and commenting!!!
I noticed that this units rely on the hardware to ground onto the unit. Overtime corrosion can occur, even though it is not visible.
Cleaning under the hardware with a wire brush may help reduce noise.
I am truly enjoying the Amplifier!
This one has a special place in my heart !!! It’s hard to believe that he was literally a basket of metal parts!
@@TinybenchI would enjoy it too. These older eico unit have really good output transformer. You won't find such quality in modern équipement unless you pay multiple thousands. My HF-60 have peerless transformer and there's a good chance those in your unit are peerless too. Incredible.
You can determine the foil side of the caps that are not marked with a oscilloscope. Just connect one side of cap to the positive of the oscillloscope, and hold the body of the cap in your hands,
Do it with both side, the side with the most deflection is the foil side.
I'm an older electronic technician and since 20 years, since consumer electronic isn't repairable anymore, I restore and rebuild vintage audio equipment.
I have 4 telefunken 7189's from 1962 waiting for an amp someday.
thank you very much for watching liking and commenting teammate! Good things come for those who wait but not for those who wait too long! Lol
Grab one on eBay. Let me know if you need help picking one.
The Harman Kardon A230 is also awesome and cheaper! And there’s a few other ones also very good!!!
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@@Tinybench I usually convert amps like this to guitar use. I have a few PA and Hi Fi amps ready for the conversion. I will be beefing up a Magnavox Phono Console from 1961 shortly. It uses 4 EL84's but I will use those 7189's in it since a 7189 is a beefed up EL84. Cheers.
@@skullheadwater9839 Hello team, mate!
I heard all other people converting the them to guitar amplifiers with amazing results and a really good tone! I also use the 7189 tube. My favorite.
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Fantastic Transformation! I absolutely love the way my HF-81 sounds after you did those same upgrades to mine. Cheers!
Hello Jamey! Thank you so much!
Thank you for the trimpot!!!
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Did you connect the 0.1uF capacitors linking the anode to the first grid correctly (outer foil)? The yellow stripe on the original Pyramid capacitors does not indicate the outer foil.
When I saw those nice beefy output transformers I figured this would turn out to be a good one. Were you using Nichicon capacitors for cathode bypass?
Yes, I was. First I use polar auto Capacitors. I put together adding up to 56 uf. I then change to one47 µF bipolar audio capacitor also from Nichicon which measured exactly 50.6 uf. That one made a dramatic difference.
Thank you for watching liking and commenting. If you haven’t yet, please please please subscribe.
Thank you once again !
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Hello teammate! That’s right. The unit have really good transformers.
Those were indeed Nichicon audio Capacitors. The green one is a bipolar audio capacitor.
Thank you very much for watching liking and commenting and if you still haven’t, please subscribe. I would really appreciate it because it really helps.
Thank you very much once again!