classe twenty five and classe fifteen

Hi there I am curious to what the differences are between these amp I am guessing that they are built the same years and they have the same design philosophy but the twenty five is the higher model, i cant seem to find to much info on the 25, any info would be greatly apperated.

I bought a DR-25 in 1989 to drive a pair of Apogee Stages, later used it to drive Apogee Duetta Signatures, and still use it today in bridged mono mode to drive the Martin Logan Stage center channel in my HT setup. The 25 was simply a change in name from the DR-25 since Dave Reich (DR) left Classe' in about 1991 and they had to drop the DR in the name.

The 25 is an excellent amp. It outputs 250 w/ch into 8 ohms and doubles up as the speaker impedance halves (500w/ch into 4 ohms and 1000 w/ch into 2 ohms). It delivers lots of current as well. It runs relatively cool for a high power design and is as reliable as a brick.

The 25 is refined and dynamic, if a little dark, and can easily drive most speakers with low efficiency and/or low impedance loads. Mine has been in service for 20 years and is still going strong. Never ever had it go into protection mode, even driving Apogees and Thiels at high volumes.

I never owned the 15 but did try a DR-10 before (quickly) trading up to the 25 and there was no contest. The 10 was dull and lifeless compared to the 25. Even though I did not have the money at the time for the 25, the difference was so profound that I bit the bullet and traded up within a week. Can't recall exactly how I swung the extra $2500 for it, but I did and it has proven to be one of the best audio investments I have made.

I have heard the fifteen in a few systems and feel that it is, predictably, halfway in between the 10 and the 25. My advice is to hold out for a 25. You will be glad you did.

Good luck.
I was a Classe dealer for many years and concure that the 25 is an excellent amp. The 15 was also very good, but the 25 was better.

There were actually a few small changes from the "DR" series to the "numbered" series:

The improvements to the Ten, Fifteen and Twenty Five vs the DR-10, DR-15 and the DR-25 are as follows:

* Current delivery to the front end was improved with better impedance matching between supply and signal bearing circuitry.

* Amount of input stage regulation was reduced.

* Output stage emitter resistor values were changed.

These changes resulted in the new amps sounding more alive and having more "jump factor". The DR series were a little darker and warmer sounding.

I still think the best sounding Classe amps were the DR3VHC and the DR8 and DR9.

I thought the same thing, but when I called B&W/Classe' Audio about 2 years ago to inquire about having my DR-25 upgraded to Twenty Five status, they told me that any changes between the models were extremely minor and that there would be no audible difference.

I'm sure that you are right. As the original owner, I was not entirely pleased with B&W's/Classe's reluctance toward helping me with that. I actually tried to contact Dave Reich, but apparently he is no longer involved in audio.

DR probably works better with forward speakers and the Twenty Five with laid back ones. Regardless, it is a hell of an amp. I don't think I would kick either out of bed ;)

Always heard good things about the first Dave Reich designs, but never actually heard them. Based on specs, they were not rated high on wattage, but I understand that ran in Class A all the way to clipping?

If you look at the product literature, (I still have some), it lists the amps output(s) as A/B. I swear though, that Glen Grue once told me that the amps do run Class A up to a point, but I really can't confirm or deny that. I always thought that they did. I had a pair of DR8's running mono and LOVED them on my Apogee Stages and I had a DR3VHC on a pair of Acoustat Model Sixes that ROCKED!
Sorry, I needed to clarify that the DR3, DR3B and DR3VHC were indeed Class A amps. The DR8 and DR9 were listed as Class A/B amps, but "might" have ran Class A up to a certain level.
I owned both the Twenty Five and the DR25 in the same system, and much preferred the Twenty Five, despite Classe telling me the technical differences were minor. I found it more dynamic, alive, open sounding. I originally explored the Twenty Five, already owning the DR25, after reading the Stereophile review, where the reviewer (LG I believe) very much liked the Fifteen and did not like the DR15 at all. My speakers at the time were Snell B Minors.
The BIGGEST change between the DR-25 and the Model 25 was the removal of Dave Reich's name off the internal circuit board and replaced with Glen Grue's name. I still have the original DR-25 and Model 25 promotional literature and there is NO mention of any updates nor changes to the specifications. Dave Reich is a designer, Glen Grue is a marketer.
The worst power amp I have ever owned by far was a DR10, which was bland and inspid to a point that it made everything sound like a loud AM radio! I replaced it with an old, old Son of Ampzilla which was superior in every way, and sounded far more powerful and snappy, although its rated power was quite a bit lower. Ulimately a pair of the rare-as-hens-teeth Exposure XVI monoblocks showed what a huge amount of music was being strangled to death by the DR10s. I ended up giving the DR10 away.
I don't doubt you had a bad experience with the DR-10. You don't say what speakers and other equipment it was mated with. Proper matching is everything. I've been in this hobby for 40+ years and have owned more amps (tube and solid state, mid-fi and high end) than I can count on the digits of both hands and feet. Not one of them ever came close to sounding like an AM radio, not even the Phase Linear 400 Series 2 that I have in my collection. Peace.
I run the 15 amp with a tube preamp, specifically a Modulus 3A preamp. I am very happy with the marriage.
Hey, Brf, I think the biggest change was the face plate (removal of DR from all model names) that would be the most obvious to most people. (Even the next gen of Classe (when the Fifteen change to the CA-150) was the same amp.

I like this Classe series and still own a Fifteen. Thought the bass is great, the mids and highs lack allot of detail but still sound okay, but no match for the inter detailed mids and highs from Krell of the same vintage. just mho.
The difference between the 15 & 25 are that the 25 has more pairs of output transistors.
The 15's bass was the equal of the KSA-250.
The Classe 15's bass is no where near as good as the Krell KSA 250. In fact, very few amplifiers can match the bass impact and depth of a KSA 250. Besides, what do you know about own Merlins :-)
Yuck, yuck, yuck.

Dick Olsher(I think)reviewed it in Nov '94. I purchased a '15 based on this review after I returned form Daharan, Saudi Arabia(volunteered for 91 days temp duty to afford equipment since the pay was tax-free once you entered Saudi air-space).
I have bought a used Twenty-Five to drive a pair of KEF 103.4. It has matched pretty nice.
Appreciated if someone could share the manual/instruction with me.
I used a DR-10 for several years, and replaced it with a CA-300. The 300 was a major improvement across the board. More detailed, more dynamic, and a more even tonal balance. In looking at the circuitry inside, I noticed the DR-10 had a coupling capacitor whereas the CA-300 was direct-coupled. The 300 also had a large number of small power supply capacitors and the 10 used a single pair of large caps. Classe mentioned the power supply changes in their literature at the time.
This is a question is ear marked for "mofimadness" (the Classe dealer).
Mo - you were saying a couple of things.
#1: that the DR-9 was 1of your faves. Is it a sweeter amp than the Classe' - 25?
#2: you said you ran your a pair of DR-8's in mono. I ran a pair of DR-9's in mono & the amps sounds way better in Stereo than it does in mono, there's no comparison! That's why I'm looking at a Classe' - 25, I need the power. Did you do anything with your DR-8's other than flip the switches at the back?
#3: Between the Classe' - 15 & the Classe' - 25, which did you prefer & why?


I had the DR25 Nice robust amp).

From memory I recall (long time ago) both DR25 and DR15 had balanced inputs, these were a bit of a hoax as they were just an opamp that summed and they fed into the single ended input afterwards.

Better sound is obtained by just using the single ended inputs straight into the discrete input transistors.

Inputs are also capacitor coupled, I replaced the 5uf electrolytic coupling cap for a better quality plastic one for a further improvement in sound, and increased the Class A bias a bit more so the heatsinks ran at 50c on a hot day 30c.

Cheers George

#1: that the DR-9 was 1 of your faves. Is it a sweeter amp than the Classe’ - 25?

Yes.  Sweeter, warmer and smoother.

#2: you said you ran your a pair of DR-8’s in mono. I ran a pair of DR-9’s in mono & the amps sounds way better in Stereo than it does in mono, there’s no comparison! That’s why I’m looking at a Classe’ - 25, I need the power. Did you do anything with your DR-8’s other than flip the switches at the back?
Your’s are the first comments that I remember liking the stereo version over the mono better? I had quite a few customers come back and buy a second amp for mono. I guess it would depend on the speakers they were driving, but for most of the demanding speakers of the time, the monos were the way to go.

#3: Between the Classe’ - 15 & the Classe’ - 25, which did you prefer & why?

The 25 was better. Better bass control and extension. Better grip on the high frequencies, effortless power when needed.