|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
173.60.203.140
Got one!
I love the difference a change of amp can make with the Quads. In the case of the Futterman, it's amazingly dynamic but a little muted in the midrange. Is that the expected experience with the H3 and OTLs in general?
Follow Ups:
Hi,
Regarding a switch; I don't use one ... just plug it in and out without problem. However, if you wish, a switched power bar is a good solution. Know that the line is not fused in this design.
Regarding film caps for the output couplers,good options are available from Unlyltic.
I don't know what you mean by "muted". That one word does not convey your possible meaning to me. In the pure sense of the word, no, the Futterman/Quad combo should not sound muted in the midrange. It is a match made in audio heaven and should sound glorious. If your H3 is very old (as they all are) and has not been refurbished, you may have some suspect coupling caps. The weakness of the design is that it is capacitor-coupled to the speaker, and in those days Julius had to use what was available, which were old time electrolytics. You may need to refresh those.
Thanks for the input. Sorry, by muted a met really that the midrange was buried in the mix. After more listening, I realize there is something definitely wrong because the acoustic guitar in every record I own is somehow lost. And voices are sounding like they are coming from behind a curtain. Highs and bass continue to be wonderful. I'm taking it in to be evaluated tomorrow because I really want to make this amp work for me, something to enjoy while I save for M60s! :)
Hello,
I have an H3 and Piquet refurbed ESL57s. I would not call the that combo muted at all. It is extremely revealing in the midrange. It could called a bit grainy but not muted.
There are numerous good-all couplers and the big electrolytic cans that need to be changed. I will eventually put good quality film caps to replace the electrolytic cans in mine.. if you not have done this work you should before you pass further judgement.
What output tubes do you use in your H3?
6HB5s. I just opened it up with my local tech and it's absolutely been redone...actually completely rewired. Totally clean. It's beautiful. On the schematic it show a couple of things have been taken out of the circuit but I left that with the guy that's checking it out. I think I blew a tube yesterday, there's suddenly a ton of distortion equally on both channels so we think its either the OA2 or 6EM7, but it could also be a power supply problem. He's checking it out this week and then we are going to listen to it together and see how the midrange is.
What output tubes do you use?
It sure sounds like you have a problem with a bad ground at the speaker terminals. Check and see if the speaker terminals have a common ground connection. If so, I suspect it is bad.
Thanks. Just got a call and there was a fuse problem of some sorts that they worked out. I'll start listening again tomorrow and report back how it sounds long term....
Hi,
I use the 6FW5 octal sweep tube. Make sure the regulator tubes match the circuit as the labels may not really indicate the real tubes. i.e., my screen regulators are 6dr7s yet the chassis is labled 7734.
He used whatever tube was in fashion(cheap, I understood that he tested new tubes for some manufacturers or distributors) and did not change the silksreen on the chassis.
Change the diodes in the B+ and bias as well they are old types and leak.
Good luck with it , it really is a very nice amp.
What do you do about a power switch? I messed up a tube by mishandling plugging and unplugging. Did you install a power switch or do you have online on the cord? Thanks.
Thanks for the tips!
As I recall, based on the last Futterman amps I owned which were the giant Prodigy OTLs once made in Texas, the necessary coupling capacitance is of fairly high value, such that one would be hard-pressed to achieve the required value with film caps. What I did was to bypass the electrolytics with a 10uF Infinicap. High voltage types are not necessary in this application; 200V rating is overkill. Then I bypassed the Infinicap with some smaller value film types. This really paid off in sound quality. Nowadays you might consider use of even higher value Mundorf film caps made for speaker cross-overs in this application, or motor-run caps.
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: