If a Threshold preamp is in your mix, I'l.l add that I prefer the sound of our FET Ten/e (balanced, but with SE connections) more than our FET Ten/hl. This is pretty much with any of our amps, including the Forte.
@GKTAUDIO thanks for the tip, I don't run balanced connections anyhow, and already passed on a few F44s and Ten/e's both needing some update work, and gets to be too costly to achieve the desired result for what I need. Appreciate the thought, If something else comes to mind with 2-RCA input and 2-RCA output, will keep an eye out. I may go a different route, gotta friend who's been testing a totally custom ground up pre. Friend's tech friends built for him, all nice bits too. I'm looking for best value and longevity, and don't plan to resell it. Will keep an eye out, Thanks a bunch.
@decooney - the FET Ten/e is not currently connected in balanced mode. I do find the frequency response better than the /hl however, which I think is due to the rather different circuit design, even in SE mode. However, there are so many good preamps out there in the $1k range you will have a hard time deciding!
Ain't it the truth! Depending on options that you want in a preamp, many of them are better than I remember hearing in the past. I mean, there have always been outliers that were heads and shoulders above the pack, but it seems to be more common in my experience.
Preamp Update:
Picked up a matching bone stock Forte' Audio F40 preamplifier, has the outboard power supply unit, manual volume control (which I prefer in this 2nd system), and dual RCA Pre-Out which I needed. Seems to pair very well with the upgraded Forte' 3/1A amplifier.
Running all Cardas interconnects and speakers cables, a BorderPatrol SE-I R2R DAC, and the entire combination is providing a very nice "cohesive" sound is how I can refer to it. Nice wide sound stage, depth is pretty good. Really like the tone and texture once the amp and preamp are all warmed up. The preamp is exceeding my expectations in this pairing/synergy. I wanted to see if [same-brand model/range] level of pairing would matter.
I've been comparing to my other 6SN7 triode tube preamp paired with the Forte' 3/1A. The Forte' 40 preamp is holding up well. The 6SN7 preamp might have a slightly deeper sound stage compared to the SS Forte F44, but the F44 has a really nice tone, plenty of sound stage in all directions. The word "cohesive" tone and sound keeps coming to mind with this same-brand pairing, fwiw.
Picked up a matching bone stock Forte' Audio F40 preamplifier, has the outboard power supply unit, manual volume control (which I prefer in this 2nd system), and dual RCA Pre-Out which I needed. Seems to pair very well with the upgraded Forte' 3/1A amplifier.
Running all Cardas interconnects and speakers cables, a BorderPatrol SE-I R2R DAC, and the entire combination is providing a very nice "cohesive" sound is how I can refer to it. Nice wide sound stage, depth is pretty good. Really like the tone and texture once the amp and preamp are all warmed up. The preamp is exceeding my expectations in this pairing/synergy. I wanted to see if [same-brand model/range] level of pairing would matter.
I've been comparing to my other 6SN7 triode tube preamp paired with the Forte' 3/1A. The Forte' 40 preamp is holding up well. The 6SN7 preamp might have a slightly deeper sound stage compared to the SS Forte F44, but the F44 has a really nice tone, plenty of sound stage in all directions. The word "cohesive" tone and sound keeps coming to mind with this same-brand pairing, fwiw.
Question for you guys and others @ItsAllInMyHead @Ixnay @Mikerodrig27 @GKTAUDIO.
Need your input and advice if I may ask. I'm considering listing my upgraded and updated Forte 3/1A Soderberg Class A 50w amplifier and possibly the matching Forte F40 preamplifier to go along with it at a fair price [if someone buys both]. The background reasoning is the Forte' gear was to be my backup system during the post-covid era tube shortage for my main system. I have multiple backups of tube sets now. No longer an issue. While the Forte' is a beautiful sounding 50w Class A amp, and best low-cost way to have real Class A from Pass (classic Toshiba cursive OPTs too), unfortunately I'm not using it as much now that I have plenty of tubes for my main system. Nice clean amp and preamp too, hate for it to sit.
If I were to list both for sale, is there a good spot where the Pass collectors like to hang out looking for this gear? Much nicer than the kits too. Shall I try USAM or Audiogon or eBay or other ideas? Note: Because it took me a few years to source the amp and preamp before Jon did the upgrades, I prefer to sell to the right buyer who knows and appreciates what it is - - versus selling it to someone who just likes to cycle gear to try it. Not in to selling these two pieces to a gear-rotater. type and someone who wants a Soderberg upgraded amp is the right target buyer.
Thanks in advance for your advice. Where to list is best in your opinion?
Need your input and advice if I may ask. I'm considering listing my upgraded and updated Forte 3/1A Soderberg Class A 50w amplifier and possibly the matching Forte F40 preamplifier to go along with it at a fair price [if someone buys both]. The background reasoning is the Forte' gear was to be my backup system during the post-covid era tube shortage for my main system. I have multiple backups of tube sets now. No longer an issue. While the Forte' is a beautiful sounding 50w Class A amp, and best low-cost way to have real Class A from Pass (classic Toshiba cursive OPTs too), unfortunately I'm not using it as much now that I have plenty of tubes for my main system. Nice clean amp and preamp too, hate for it to sit.
If I were to list both for sale, is there a good spot where the Pass collectors like to hang out looking for this gear? Much nicer than the kits too. Shall I try USAM or Audiogon or eBay or other ideas? Note: Because it took me a few years to source the amp and preamp before Jon did the upgrades, I prefer to sell to the right buyer who knows and appreciates what it is - - versus selling it to someone who just likes to cycle gear to try it. Not in to selling these two pieces to a gear-rotater. type and someone who wants a Soderberg upgraded amp is the right target buyer.
Thanks in advance for your advice. Where to list is best in your opinion?
^ I love that you want such wonderful gear to go to an appreciative buyer's home. With that said, I don't know that you have a way to truly know the attitude of the buyer. The swap meet here might work well. You could ask the would-be buyer a few questions via PM as a 'screening' I suppose. Maybe you'll get wonderfully lucky and someone will read your post above and think, "Hey, that's me" and send you an offer. eBay ... no. Audiogon ... maybe. USAM ... maybe. IMO, the best way to help avoid "gear rotators" is to list it at market price. If you price it too low, someone might take a flyer just to give it a whirl and you may see it for sale again at a higher price in a month.
On a total side note... the negative rail fuse on the left channel of my brother's model 4A gave it's life in service after a power surge. I went through it yesterday, and all seems to be well after a quick replacement. (A Soderberg amp also).
Good luck. I hope it's well-loved and preserved in a new home.
Our fallen soldier...
On a total side note... the negative rail fuse on the left channel of my brother's model 4A gave it's life in service after a power surge. I went through it yesterday, and all seems to be well after a quick replacement. (A Soderberg amp also).
Good luck. I hope it's well-loved and preserved in a new home.
Our fallen soldier...
Attachments
Thanks @ItsAllInMyHead for your ideas. Yeah, Jon installed the better power caps, soldered the bridge rectifiers on, and a few things at my request and worked with me on selecting the right SS preamp to get to match it up. Would prefer to see both units go together if I do part with the set. Not in a hurry, don't need to sell, yet more interested in a good match for the type of buyer looking for these units and upgrades instead for added musical enjoyment. I can already see myself stalling over the next year dragging my feet on taking photos or listing them yet. Thanks,
@decooney - I also prefer for something I sell to go to someone who appreciates it, but it just comes down to whether someone will pay you what you think is fair. You can't control their affection/disaffection for a piece of equipment, but you can set your price really high and never sell it, or too low and it will end up with either someone who loves it, or another who flips it. Just doesn't matter. You no longer own it and have no control.
As this equipment gets older, the population to whom it appeals tends to get smaller. Forte was not the flagship brand, so although it sounds and performs great, I think it will continue to lose traction to more iconic brands/models, no matter who worked on it to improve it. As hard as it is, I have had to realize that I have gear that I value more than most buyers, and price realistically if I really want to sell it.
Not sure I can add to what @ItsAllInMyHead said - here on Marketplace, on AK Barter Town, or USAM perhaps. Not Craigslist. The big online auction site will reach more people and if it's priced right, will sell.
As this equipment gets older, the population to whom it appeals tends to get smaller. Forte was not the flagship brand, so although it sounds and performs great, I think it will continue to lose traction to more iconic brands/models, no matter who worked on it to improve it. As hard as it is, I have had to realize that I have gear that I value more than most buyers, and price realistically if I really want to sell it.
Not sure I can add to what @ItsAllInMyHead said - here on Marketplace, on AK Barter Town, or USAM perhaps. Not Craigslist. The big online auction site will reach more people and if it's priced right, will sell.
I have had great luck selling to people who are more likely to appreciate such a unit, including myself. I also have a Forte model3, but it was modified beyond what I would have liked and isn't really a Forte' anymore. At least yours was done right.
So, you want to sell both units together. That actually narrows down the number of buyers right there. You haven't mentioned a ballpark price and I wouldn't be able to help with that. Even though we all know the equipment, photos will be helpful.
US Audio Mart is a great place in general IME. I gave up on Audiogon years ago and never looked back. I'm afraid that is where US Audio Mart may be headed in the future though. This little market swap is just as good, since you get a much better audience with more experience with the equipment as a whole and not just the looks themselves.
So, you want to sell both units together. That actually narrows down the number of buyers right there. You haven't mentioned a ballpark price and I wouldn't be able to help with that. Even though we all know the equipment, photos will be helpful.
US Audio Mart is a great place in general IME. I gave up on Audiogon years ago and never looked back. I'm afraid that is where US Audio Mart may be headed in the future though. This little market swap is just as good, since you get a much better audience with more experience with the equipment as a whole and not just the looks themselves.
Got it. All makes sense. Not selling it to anyone who is not somewhat already aware of what's involved to achieve a Soderberg Class A amp upgrade like this. Considering all of the time and costs of sourcing a clean amp, shipping to receive it, then re-shipping back and forth for upgrades. Jon is local to me, and so I avoided some of that of course. Paid a good price for the batch of upgrades on this one, all new power caps, new bridge Recs soldered in, Cardas speaker binding posts and a few more things.
He actually compared it to other 50w Class A Pass, Threshold, and other amps on hand up to $10k value indicating this one "holds its own with any of them" on the bench lately. I will take the recommendation under advisement here to sell both together. I prefer that anyhow. If I do list it, likely on USAM later this year. Not interested in entertaining any lowballers and gear flippers, who just want to try it and resell it. Rather just keep it and play it once in a while. I listened to in sparingly over the last four months on a few weekends and it sounds quite nice. Has the older cursive writing Toshiba opt mosfets and sounds quite nice how Jon set it up and biased it for me.
Thanks again to everyone for all the ideas and feedback.
He actually compared it to other 50w Class A Pass, Threshold, and other amps on hand up to $10k value indicating this one "holds its own with any of them" on the bench lately. I will take the recommendation under advisement here to sell both together. I prefer that anyhow. If I do list it, likely on USAM later this year. Not interested in entertaining any lowballers and gear flippers, who just want to try it and resell it. Rather just keep it and play it once in a while. I listened to in sparingly over the last four months on a few weekends and it sounds quite nice. Has the older cursive writing Toshiba opt mosfets and sounds quite nice how Jon set it up and biased it for me.
Thanks again to everyone for all the ideas and feedback.
These caps are in series, so with the 2x22000uf caps the total capacitance per side is 11000uf, while the factory caps were 2x24000uf or 12000uf per side, so I would guess that there's essentially no difference, from an electrical perspective, between those two choices, at least performance-wise -- I went with the 22000uf ones because I figured (hoped) that the actual values would be a bit closer to the 24000uf target of the originals. That said, I think the 33000uf ones would be totally fine too...Just my opinion anyway, and it's worth what you paid for it.
Hey Guys, a quick Forte' F3 / 1A amp warmup and "sound" question. I had my Forte SS amp out of rotation for five months while running my other mono block tube amps. Kept all of it, sold nothing. A few regretted selling yours prior so I read you comments and held off. Just rotating back and forth every few months. Back to Forte recently -
Two days ago, fired up the amp, sounded pretty good in about 1hr. At 3hrs it become even more transparent and a little grainy sounding - almost becoming more hyper detailed in a way. Maybe even lost a little warmth and body there for a bit. Turned it off that evening, did not leave it on overnight.
One day ago, yesterday, tried again playing it for 6 hours, let it play and it was about the same not as much body to it but a little more transparent, like hearing everything I put into it, good or bad. Some of that grainy sound still there.
Today, I let it run for 1-2 hours and it was about the same as yesterday - then about 4-5 hours of warmup tonight its kinda smoothing back out some, a bit less grainy, transparency is still there but smoother, not as etchy as it had become the past few days. Smoothing out now. Odd, interesting. Even questioning own hearing a bit too, and I have decent hearing. Guitars, chimes, pianos starting to sound a little more natural again on the later part of the 3rd day. Or am I just getting use to it again... not sure.
ASK:
If you let these older amps sit aside for 4-6 months like I have and have not played them in a while like this, do they need to play a few days over say 72 hours to kinda find their set point again for components to stabilize - or anything like that?
Two days ago, fired up the amp, sounded pretty good in about 1hr. At 3hrs it become even more transparent and a little grainy sounding - almost becoming more hyper detailed in a way. Maybe even lost a little warmth and body there for a bit. Turned it off that evening, did not leave it on overnight.
One day ago, yesterday, tried again playing it for 6 hours, let it play and it was about the same not as much body to it but a little more transparent, like hearing everything I put into it, good or bad. Some of that grainy sound still there.
Today, I let it run for 1-2 hours and it was about the same as yesterday - then about 4-5 hours of warmup tonight its kinda smoothing back out some, a bit less grainy, transparency is still there but smoother, not as etchy as it had become the past few days. Smoothing out now. Odd, interesting. Even questioning own hearing a bit too, and I have decent hearing. Guitars, chimes, pianos starting to sound a little more natural again on the later part of the 3rd day. Or am I just getting use to it again... not sure.
ASK:
If you let these older amps sit aside for 4-6 months like I have and have not played them in a while like this, do they need to play a few days over say 72 hours to kinda find their set point again for components to stabilize - or anything like that?
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The quality of the mains supply (110? AC) will keep changing. Listen on Sundays during the night. In addition, take an hour's nap and don't let anyone raise your cortisol levels 🙂
The amp will sound amazing.
The amp will sound amazing.
I expect the sound to get more detailed with time and less grainy, not more.
I’d check bias in those 2-6 hour period. Seems like there is some thermal cycling going on modulating bias current more than needed.
The sinks should stay between 37-45c at idle.
Are their any capacitors in the signal or bias or neg feedback? Refresh those. It’s almost a 40 yr old amp now. Those don’t last forever.
I’d check bias in those 2-6 hour period. Seems like there is some thermal cycling going on modulating bias current more than needed.
The sinks should stay between 37-45c at idle.
Are their any capacitors in the signal or bias or neg feedback? Refresh those. It’s almost a 40 yr old amp now. Those don’t last forever.
Thanks @K-amps, I'm hearing from my local tech bias was set at 45-47c, and he just mentioned he could turn the bias down just a tad. I'm wondering if that could also smooth out the sound some more too. He's indicating 24hrs warmup after sitting around a while. I see the same types of posts with some of the older Pass amps too fwiw. I'm asking him about signal path caps now, but the main power caps were replaced, its been checked twice in the past year for specs, apparently needs nothing - BUT I will check on what you asked about in the "signal path". An old thread mentioned someting similar about different flavor caps too, so what/where/how is my latest follow-up with my local tech who works on these, former Threshold guy. Thanks
45c idle is about darn perfect. Silicon wafers produce less higher order harmonics once over 40c.
I’d replace all small electrolytics on the boards.
If you can replace the feedback dc blocker with a 100-200 uf Nichicon UES ( Muse) it will sound less strident. Maybe a tad warm too.
A metallized PP film might be even better, but it will be huge, if you can fit one. WIMAs sound a tad more detailed but edgy too, so see what you like.
Papa used the largest film cap he could fit into the Thresholds of the same era.
The Nak PA7 also uses a film cap there.
I’d replace all small electrolytics on the boards.
If you can replace the feedback dc blocker with a 100-200 uf Nichicon UES ( Muse) it will sound less strident. Maybe a tad warm too.
A metallized PP film might be even better, but it will be huge, if you can fit one. WIMAs sound a tad more detailed but edgy too, so see what you like.
Papa used the largest film cap he could fit into the Thresholds of the same era.
The Nak PA7 also uses a film cap there.
Turns out it just needed some solid warmup time after sitting out of rotation for 6 months. Heard back from JS Vintage Amp and went over the last QA check we did last summer. He instructed to leave it on for 24hrs, check again. I wanted to make sure before listing for sale. Seems to have smoothed out nicely as I recall how it sounded last summer. Turned it off last night, fired it up tonight, and sounded pretty good in the first hour.
We are consolidating a few different rooms and systems, and will be looking for the best ways to get this upgraded Forte' Audio 3 / 1A (now Class A 50w) in front of the right potential buyers for review and consideration. Also have the matching Forte Audio F44 preamplifier too.
I believe some members here felt it might be best to list these Forte' Audio F3 / F44 units together as a set. Will give that a try if that makes best sense. Thanks for the feedback.
We are consolidating a few different rooms and systems, and will be looking for the best ways to get this upgraded Forte' Audio 3 / 1A (now Class A 50w) in front of the right potential buyers for review and consideration. Also have the matching Forte Audio F44 preamplifier too.
I believe some members here felt it might be best to list these Forte' Audio F3 / F44 units together as a set. Will give that a try if that makes best sense. Thanks for the feedback.
Hi, thank you so much for these ideas!
I'm the OP of this thread and even though my unit went through some maintenance that fixed most of the issues I was having at the time, I'm still dealing with a 100hz hum, so given the age of the unit, I'll probably go ahead and replace the electrolytic caps.
But even though I know how to solder and measure stuff, I'm not an expert and I was wondering if you could use the pictures on the first page to let me know where exactly is that DC blocker cap you mentioned. Do you have any more tips? The amp sounds great, but I'm sure replacing those caps is overdue and getting rid of the hum will help clear up the signal and improve it even further, so if you have tips on which caps brand/models to use, that would be great! I'm located in Europe, so Mouser and Digikey will be my sources for the components.
Thanks!
I have one of these too and the only electrolytics that I noticed are the power filter caps, I don't see any electrolytics on either of the channel boards; lots of film caps though. Where are the board electrolytics? Anyway, I've never had any warm-up issues when bringing the amp back into my system, why would that be the case unless there's some component that's failing? The amp does run on the warm side, and to set the transistor bias, I was told, that it's set by measuring the power transistor temps and when you reach a setting that maintains a stable 40degC the bias is considered correct; which for my amp was about 38mv on each channel. And then it takes about 30min to reach operational temp. Yes, the amp does sound better after a full warm up, but I thought that had more to do with the temperature related bias settling in, and it was never objectionable anyway, but the sound did take on a more detailed quality after warm up. Now, I have heard that it's much less stressful on the switch and electronic components to leave the amp powered on rather than turning it off after each listening session, but that's not what we're talking about here, is it? Lastly, my amp is dead quite, no hum at all, perhaps I missed something but how was it determined that the hum is 100Hz, and not say 60 or 120Hz?