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You guys may have remembered when I posted a Sophia EL34 amp and we all kind of cringed at the messy layout..It isn't as bad as it looks in the photos but it's not Sophia's best work either..They have some very nicely laid out stuff and I have to admit that the physical architecture of this EL34/KT66 amp is first rate..
I want to add that even tho we criticized the direct connection in the Sophia amps,they stumbled on to something here because the elimination of terminal strips may be yielding a great sonic improvement..In the bottom circuit boards that you see,the components are directly connected to each other with the board merely holding the components..This amp was pretty easy to upgrade and they were very generous with the room to work as well.
I actually enjoyed EL34s in this amp and that included the vintage tubes but when its hooked to the big ribbons,it sounds much better with the KT66s..When it's hooked to the IMF SACM transmission line speakers,the EL34s compliment this setup very well.The IMFs are exaggerated and somewhat sharp sounding in the treble ranges but this amp with the EL34s or KT66s, make it a perfect balance and the amp really does a nice job.
While I'm not a fan of not using terminal strips,this amp with the direct soldered components seems to be on to something.
As with any amp or preamp,I did make upgrades that brought on worthwhile improvements. I installed Schottkys,Russian Teflon couplers,
35uf poly film cap bypasses on each of the 180uf electrolytics,and I put the grid stoppers directly on the sockets so they would fix the oscillation that would crop up on occasion.
The improvement is phenomenal and this amp has some very nice iron and you can run most any octal based tubes from EL34s,KT77s,KT66s,6L6gc,7581,7027,6P3S-e,and all will sound very nice.
You can always run a 7027 in a pentode amp wired for a 6L6 but not an UL amp without rewiring the sockets.
The reason I used the teflons is,I felt the amp needed a little more bite and I wanted to lift a comparative veil over the music and with the updates I did,the amp was able to do that very well.
Of the 35uf poly film caps,I used an EC Unlytic on each end with a CDE poly in the middle..The CDE and the Unlytic sound almost identical.I also changed an extension resistor that was out of tolerance..The Muse KZ bypass cap made a nice difference as well..I did have to change the power switch as it locked up but that was after I took this photo..You can see the original and the updated version.
Honest amplification is better than excessive 2nd order distortion anytime.
Edits: 04/06/14 04/06/14 04/06/14Follow Ups:
Hi Mikey,
It's nice to finally see an update on his amp, it seems to me that you've done a great job in assuring that I won't be eating up rare power tubes in less then 2 months, as I'm more then certain that was his biggest concern - yet you've managed to get more detail from it was an added bonus to say the least - as I felt it was a tad bit on the overly warm/refined side and lacked dynamics, but that's just my opinion, and I guess in the end - it all comes down to ones preferred presentation, but give me. A sense of snap/attack - peaks and valleys, or better put, drive any day of the week.
Yet, the wiring harness could've been tidied up just a bit - but I know that the owner is more then capable of doing that part over time - so, as always - Thanks for your services and helping said friend out on what was to me a beautiful amp that required just that little extra sense of TLC, and you've done a great job as expected.
Regards,
O_o scar
Mikey,
Can I mail you a few terminal strips?
LOL
Sure why not! I have a few 100 but the politically correct crowd in the audio world might bark at us.
Honest amplification is better than excessive 2nd order distortion anytime.
Mike, how do you get this thing to be quiet? I know it must be, to pass your criteria. It's just that if any guitar amp had what appears to be that bird's nest wiring --- it would hum like crazy and maybe unstable.I go through the wiring and lift or lower all signal lines. Put AC lines (like heater and PT) in another plane. And try to make wires cross at 90-degree angles. In these guitar amps, it makes quite a difference. Eliminating some hiss, hum, and that annoying tremolo circuit "ticking."
Are there some tricks that you use to help reduce inducted noise and hum? Some circuitry tricks?
Thanks.
_
1962 Pro:
DIY Princeton Reverb:
Edits: 04/07/14 04/07/14 04/07/14
There is a lot more gain in a guitar amp.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Tre', thanks for the response. Never thought about gain and amplification of noise and hum.I would think that lead dressing and layout would help, even in low gain setups. Can't hurt. Right?
Sure would make repairs & mods a lot easier.
Edits: 04/07/14
I think so FL. Just because we cannot hear anything obvious - like hum - does not mean poor layout is not having an adverse effect.
If an amp amplifies the difference between signal and ground and the ground (or signal) is grubby... As Tre has pointed out, high gain can make (some of) these adverse effects more obvious.
I think that minimising connections to posts/ tags/ turrets and keeping components away from metal chassis perimeters as in the Sophia amp is a path to minimising some adverse effects. However, I don't think they are realising all the benefits of this due to what looks to me like a convenient and haphazard implementation applied to the amp in general. Further, I have concerns about the reliability and maintainability of their implementation, which is partially confirmed by other's experiences with Sophia amps.
Cheers.
“As long as we have any intention to be right… we should be wary. So long as words have the slightest ego attachment, they are dishonest.” Charlotte Joko Beck
I think that minimizing connections to posts/ tags/ turrets and keeping components away from metal chassis perimeters as in the Sophia amp is a path to minimizing some adverse effects.
On one hand, it's a band aid for schotty workmanship.
That rats nest, with wire and leads piss poorly dressed can also be the root cause.
We all agree (except xxx) Design, Layout and Parts selection make for a sound implementation without/minimal headaches.
I use solder terminals to make mechanical connections; multiple wires are twisted and wrapped around the terminal.
Sophia builds red-neck dreck at champagne prices.
IMHO/HE of course.:-)
Cheers,
W
"I would think that lead dressing and layout would help, even in low gain setups. Can't hurt. Right?"
Sure, but it's really important when there's a ton of gain.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
I pretty sure this person would appreciate knowing the thing isn't so gawdawful as originally portrayed.
I didn't see that review but the guy that wrote it,that's who's amp I have.He heard my McShaned Hf87 and my upgraded Fisher 400c on the NewForm Research ribbons and he was awestruck so after I did that,I knew I would have to step it a notch or two..They wanted to hear the big ESLs but my basement is in disarray right now so that will have to wait until summer when the remodeling is done..
Honest amplification is better than excessive 2nd order distortion anytime.
Edits: 04/07/14
Well it was mostly the layout that reviewers if you recall criticized..The updates I did helped a lot and I think he will notice it the minute he hooks it up.It isn't the way I would do an amp but it does have some nice points and I have seen Sophia's other amps which look really nice.I still prefer the HF87 and HF50s for EL34 amps but this is running as an integrated amp and being its a passive preamp,it would sound even better if you could run a separate preamp.
Honest amplification is better than excessive 2nd order distortion anytime.
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