Preamp possibles for system...

I am currently using a Belles 21A auricap but have been itching to try something else for possible system improvements. The amp is a T-hold S/500 ll with an Arcam CD23 and Polk SDA-2's with RDO-194 tweets. All IC's/PC's are Morrow Level 3/4. My 22'x35' listening environment is slightly harsh with wood floors and a fair amount of glass. Musical taste is quite varied at moderate volumes.

In general, I feel the base or low level frequencies are a bit forward but not crisply defined. Also the high frquencies seem somewhat constrained or maybe rolling off early...using others terminology I have read. Almost as if the singers are behind the band. Not always, but on enough recording's I notice it.

My previous amp was a Nak 7. Everything else staying the same, I recently switched to the T-hold S/500. I literally would have wrote an exact opposit review of the systems traits critiquing it with the Nak. I was certainly a VERY good way.

I have read that the T-hold amps liked certain pre's. Here is a list I have gleaned from some research. I have not seen all of these available, so some maybe out of the question. I would be gratefull for any input to try and target my continued refinement.

Sonic Frontiers line 3
Aestetic Calypso
Audio research LS25 mk1 or 2
Modwright 9.0se
Klyne 7

Would you consider replacing your Arcam player? CD players have significantly improved over the last 10 years. Since you have vintage gear is everything running to spec?
Why not look for a Threshold T2 to mate the S/500 II with?
Dayglow...Yes, I would consider replacing the CDP. I know the amplifier is running to spec as it was just recently checked out. I am currently getting ready to have the crossovers reworked on the Polks.

Jmcgrogan2...No particular reason on not having the T2 on the radar. Can't say that I have ever stumbled across one used on the forums or read them discussed much in my research. Certainly I do not put my entire opinion on that but just something I have not been exposed to.

I appreciate the opinions to help me pick a direction for funds to be used.
IMO the source dictates the potential of your system.
Sounds logical. Here is a few CDP's I have seen reference to with Pass gear I think would be in my budget. I think most of these are still near the ten year old mark. Would they be a marked improvement over the CD23?

Ayre Cx-7
Accuphase 65, 67
Arcam 37
Marantz 7si
It appears you want a more aggressive detailed/dynamic and extended player. Of the ones you mentioned the Ayre has the characteristics above. The Ayre is currently selling the Evolution/MP model. With the Ayre I would look at softer(less edgey)pre-amps. Jeff Rowland could be a great choice if you want to avoid tubes.
The Klyne has some interesting Design solutions which can make life pretty good
- 2 separate Gain knobs (for each channel), this feature allows the owner to match it to any connected amp (or you can use it for sources, too)
- some say, sonically it closes the gap between Transistor / Tube sound
- reliable
- external power supply
- it can be ordered with internal Phono Stage when you want to listen to Vinyl one day
I too will through my opinion behind Ayre products. Although I ended up purchasing the latest C5 model I did bring home the C7 and thought they were both as natural sounding as anything I've heard, including analog.
What 12AU7 tubes are you running in your 21A? I had the same pre-amp, and have rolled quite a few NOS tubes in it with fairly dramatic results.
I would like to extend "Thanks" to everyone who took the time to respond. The info has given me both something to ponder for a sense of system direction along with items to keep an eye for and contiune research on.

Bigshutterbug...I am using the original Mullard's currently. One of my reservation with the 21A has been comments associated with it not matching the Threshold impedences well. It truly tamed my previous Nak 7 compared to a Rotel pre I had used originally. I have been using it very happily until recently adding more and varied music and also moving into a larger home.
You might want to try replacing the Mullards with a pair of Amperex Holland 1960's 12AU7's. The Mullards are warm and rich 12AU7s with sweet highs, where the Amperex 12AU7s
are faster, more lively and energetic, with more extended highs and a tighter, more defined bass. Give some a try...
Thought I would post an update. I was mistaken about the Belles preamp tubes being Mallards. Turns out they were RCA 5814A's. I installed the oem equipped Mallards for a oem base-line test. Heading Dayglow's advice I also purchased a Bryston BCD-1 in order directly compare with the former Arcam.

With only a very short time of listening the changes in tubes and the cdp are quite dramatic. Music is certainly brighter and appears larger or more forward. Maybe even too much for my taste and/or listening environment. Lower frequency's and or/bass do seem slightly crisper. I am hearing things like string squeaks and low frequency tones clearly that were barely noticeable before. I feel it was a good direction of funds and will give me a decent standard to experiment with via different tubes and some room changes.

Hearing what I do know is sort-of taking my attention off the preamp and maybe directing it to the speakers...if my desires were to soften things up. Does that makes sense?
As I typically do, I suggest finalizing your speaker choice before doing anything else. The speaker/room combination will have more total effect than anything else.
With that said, re: preamps with the Threshold S/500 Series II. Many of your choices appear to have balanced outputs, something your Threshold series amp doesn't accommodate. Keep in mind that adding true differential balanced operation to gear is not an inexpensive consideration. If your intent on keeping your amp (and a very fine amp it is) then perhaps you might want to partner it with a pre that might have used the extra costs otherwise spent on true differential balanced operation on other parameters. That is not to say that a balanced pre should automatically be disqualified because you'll be using it's single ended output, or that balanced operations doesn't have it's virtues.
Again, I suggest you reconsider your speakers before doing anything else.
Thank you for your input Unsound. My budget keeps me having to research and watch the used market to build a system I know I would otherwise not be able to own. I am very fond of the amp as I was the Polk speakers though I completely understand thier place and time in the marketplace. My current listening sessions seem to be reflecting new shortcomings in the speakers from either design or thier age. I hear more detail than ever but the general tone and low frequency quality is not not where I would like it.

Unsound, could elaborate on what perameters would be usefull in a single ended optioned preamp selection?

My listening area is quite large. It encompasses a great room concept floorplan with the speakers being located nearly against the front wall. A couple speakers I have been focused on are the Dunlavy Contata's or Legacy classics/focus. Seems they are capeable of filling a large area and may be more leniant than many at being located near the front wall with thier woofer design. The prices I see would be my upper price threshold but realize the importance to the system.

A true differential balanced unit will have to double the number of parts in some stages. So if the same money was spent on less but better parts, the parameters would change.
I've always said that all things being equal, balanced is better, but I guess if one includes budget, that might not be possible. So it would seem to me, that if you aren't going to use the benefits of balanced operation, then money spent on parts for balanced operation would be superfluous, and better spent elsewhere. Whether or not this actually plays in practice is another ball of wax.
FWIW, I'm a big fan of the Dunlavy's. Once again, I suggest deciding on your speakers first, and then deciding on the supporting cast of components.
Looks like the Dunlavy's will indeed be my next speaker. Any insight on what single-ended preamp possibles would compliment the combination with a T-hold S/500 II, Bryston cdp, and full Morrow cables/IC/PC set-up?
Do you have only the one source (CD)?
I'd suggest getting the Dunlavy's first, and then see if you like it with the Threshold before getting a new pre. The Threshold might have more power than the Dunlavy's need.
Yes, just a CD player.
A true differential balanced unit will have to double the number of parts in some stages.

This is not correct. It is true of *balanced* if not differential, but if *balanced differential* the parts count is less than double.
The Dunlavy Contata's finally arrived and are now mated with the Bryston cdp, T-hold S500II and Belles 21A pre. Aside from the larger and more powerfull presence the Dunlavy's provide, much of my earlier tonal critiquing generally applies. I would like a crisper, tighter control of the lower frequencies and bass. In general, the mid and upper ranges are pleasing though seem to lack an overall clarity or depth to the finer details. Reading others use the phrase "a veil has been lifted", seems to best describe what I am hopefull of.

The point was offered up that I may be over-amped. I never thought of that possible and am unsure how to gauge that.

Perusing the archives and available used items, I have continued to update a list of possibles for experimenting. My budget would preferably be under $3K. Thanks for any input.

Pass Labs XP-10
CJ premier 14 or 16LS MKII
Ayre K1xe
JR capri
Hovland HP200

I can't help but wonder if your problems might be more room related than equipment related.
Thanks Unsound...Good possibility. I assume you base that on me mentioning how bright or harsh some of the rooms large material surfaces are. The low frequencies negative affects on "everything" I know are real. It definately sound better at low to moderate volume levels.

Putting the systems performance aside, I do not feel the Belles is a good match. The gain is obviously quite high as I rarely am above 9:00 o'clock on the volume and very loud is often near 10:00 o'clock. Makes for difficult fine tuning. It also is Black and I want something more closely matching the other components...nitpicky I know.

I am noticing a tweeter issue on one of the Dunlavy's. I am hoping I can find a worthy replacement. The more I am working my way through my music collection the more impressed I am.
Well I did some more testing with impromptu room treatments and speaker placement. My conclusion is that on low volumes the bass seems to be fairly controlled. As the volume goes up the low frequencies start/can get muddy, for lack of a better term. I am really itching to compare the Belles directly against another pre. It is either that or start purchasing tubes for trials though aesthetically the piece is also off.

The Cantata's tweeters were replaced with ScanSpeak D2606/9220. Madisound recomended them as direct replacements for the original Vifa D27TG-35. They are made in Denmark and were exact copies. I am quite happy with thier sound even being fresh.
I, was happy with my system, but I decide to upgrade my Pre amp, I went from the Cary SLP 98 to

what I consider one of best tube Pre amp the SLP 05, please go to you nearest dealer and give it a try

you would never regret, it please let me know

what you think and good luck on you search.
I am waiting for a pair of the Amperex Hollands to be delivered Bigshutterbug recomended. With a budget of near 3K I have not seen much used activity for anything on my shortlist. I will try to search out a listen on the Cary SLP-05...Thanks Tango.