|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
97.95.43.235
Every once in a while I get the urge when I'm up grading class assignments when I can't sleep,to try some of my more forgotten vintage output tubes.
Tonight,the amplifiers were my Eico HF60s that I had rebuilt about 10 years ago.In the Eico HF50s and HF60s and HF35s,a 50uf film cap off the rectifier in place of the paralleled first two 20uf sections is a must to really get these things to open up.The cap I have been using is a 51uf at 630v Solen and it's one of my favorite caps because you don't have to increase the hole size to put the connections thru as you would with a motorrun cap.Downstream I went with a dual 100uf F&T and I will change those over to a pair of 60uf panasonic film caps that will fit underneath the chassis just fine.These amps need a polishing and a repaint on the Acrosound transformers along with the power transformers.I will also be putting in a choke as I did in my HF50s with the Gilespie mods to run KT88s..You can see I didn't put new cords on yet and those will be the standard 14gauge,2 conductor. The bias and balance pots are all new as well.
What I have realized tonight when running the old Philips metal base EL34s is,you have to have bias and balance spot on.The tubes also have to be matched pretty well within at least 10% of each other because they are not as forgiving as a 6L6 or a KT88 even if you have them balanced and biased.
I was streaming jazz radio on my I pad and I was going direct into the amps and I wasn't using the DAC either.
I was using the Newform Research 645 ribbons and then I switched over to the TDL transmission line monitors we just picked up.Both speakers sounded very detailed,very controlled,and very open with depth from here to a back alley.To be fair,I have always liked the EL34 on the HF50s and HF60s because it is done right because of the iron and the circuitry.
Steve-0 told me try the EL34s in these amps as opposed to the HF87 I was always using for the test and he was right.The amp really does make a difference.Tonight I will try the Genelex Reissue KT77 once again in these amps which I call old faithful because they sound fabulous in any amp I've put them in. It should interesting.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Edits: 01/25/17Follow Ups:
i can see there is different version of the 60uf panasonic film caps.
some are 500v some are 800v rating. which one did you use Mike ?
One of the best combination of output tube and rectifier, I've heard.
Steve
In which amp were you using them? I did use them with the metal base GZ34 when I did the test.Now I'm back with the Genelex Reissue KT77s with the metal base GZ34 and they hang right with them in the HF50s and the HF60s.I only liked the metal based EL34s in the Eico HF50s and HF60s.In other EL34 based amps.I thought the five staple Telefunkens were very good but I always end up back with RI KT77.
Another great tube is the Shuguang Treasure 6CA7 and I almost bought some but when the reviewer said the RI Genelex KT77s were just as good and were half the price,I let it go.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Years ago. Comparing two 40-watt 1962 model Marshall combo amps. One with GEC/MOV KT-66 and one with metal Amperex EL34 output tubes. Both had the original ROLA-Celestion alnico 12-inch speakers.
Both amps were LOUD. Very loud. The Amperex EL34 had a creamier tone. Smoother mid to high transition. IMHO. The KT-66 had more clear high notes, good midrange. Both had excellent bass.
Great amps. Don't make them like that anymore. :(
Are those the same metal base EL34s that I used to find in the original Dynaco Mkii's?
Back in my Dynaco days I bought several MKii's and they had the metal base EL34s. The Japanese were paying OUTRAGEOUS prices, like $750 a pair, so how could I justify keeping them. Hey, it financed my hobby at the time.
Besides I would have eventually done something stupid with them anyway.
Those were in the Dyna Mk2s and Eico HF50s and HF60s as well as the Scitt 240s and the Scott 280s.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Why the change to the Panasonic caps? I thought that F&T were suppose to be really good. At least the Marshall crowd digs em.
Looks cool though. I wish that I could hear it in action.
The Panasonics I'm putting in are film caps where the F&T is a lytic.The JJ and F&T lytics are very good but I prefer poly film caps for filtering when I have enough room. Notice the big Solen 51uf poly can? That's what really makes these amps get after it.I could put another 51uf solen on top and one more underneath but the Panasonics are cheaper and smaller for what I need.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Are ARC poly caps ok? These are not in a metal can such as motor run caps.
You mean ASC and yes,they are excellent.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
I have to try this sometime. i never did the large film cap in the power supply thing.
Mike, I will be interested to hear your comments on the GL reissue KT-77 tubes compared to the EL-34. The reissue 77's have been among my favorite tubes ever since I got them.
The Reissue Genelex KT77 is my favorite EL34 drop in.In the octal tubes,I favor tetrodes but I give these metal base their just due.I'm heading to school but tonight I'll try some other EL34s in the same amps and the KT77 reissues.Here is a session I did a few years back.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
I once (long ago in my newbie years) flipped a scuzzy old amp that had a pair of those for output tubes. I am sure the guy who bought it knew what they were and threw the amp away and kept the tubes. Not one of the smartest moves I ever made.
Edits: 01/25/17
Those are very serious EL34s. Fine audio transformers too.
Jim
The Chicago Iron in the HF50s is better sounding IMHO.The Acrosound T0-330 are really KT88 transformers.I have three pair of HF50s.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: