Thank you for clarifying those things, Mr. Sarmento.
Would you be able to confirm that the Crimson 275 is spec'd with 15W Edcor output transformers? I have asked that question to Frank Malitz/Bob Carver several times and have not heard back. There are at least two units purchased from authorized dealers with 15w Edcor transformers in them. It would be helpful to know if this is OEM specified.
I think some of chatter has to do with the perception that there is a lack of transparency about the amplifier. Mr. Malitz has not provided straightforward answers to simple questions--instead he uses sales techniques to respond. For example. when asked about the PT and OPTs in this amp, Frank responded with paragraphs explaining that many speaker manufacturers recommend the Crimson 275 with their loudspeakers and they wouldn't do so if it were not a lovely sounding amplifier.
That may be very true. But the question is a simple one--Were the Edcor transformers specified in the design or appropriate for the design?
While I appreciate how some may feel that the social media "pitchforks" and "mob" are out in full force, I think it's important to keep something in mind: Folks have legitimate, simple questions about the amplifier to which they cannot get responses. This amplifier cost many of us $3k (with tax) and when we get evasive, salesy responses--or, in the alternative, radio silence--it only increases the skepticism.
For the record, I love Bob Carver's history and him as a person. The amp does indeed sound good with my high efficiency speakers. I'd love to have Amir and any ASR gang over to blind A-B it against some of the top performing spec-wise amplifiers. That's part of the fun.
That said, folks have raised these salient questions to which there has been utterly no response--just conclusory statements by Malitz and now Bob. Maybe you could help answer them as your firm looks to have built a good number of copies.
1. Is mounting the DC restorer circuit by gluing it vertically to the chassis part of the design?
2. Is mounting the meter to the chassis by gluing it part of the design?
3. Are the Edcor 15w OPTs part of the design?
4. What gauge hookup wire is supposed to be running from the PCB to the speaker output terminals?
5. Does the design-manufacturing process allow for substitution of Panasonic film caps with Suntan brand or other lesser known caps?
6. Have there been reports of transformer hum? I have owned two units and both hum/buzz at the transformers with no signal and volume totally attenuated (not a sound coming from the speakers, but buzz/hum coming from the transformers (all 3)?
7. Frank Malitz stated there was a problem with transformers when the vendor deviated from specification, and that resolved. Would that vendor be Edcor? What can be done to silence the transformers for those with those issues?
8. Grounding. Are you aware of what many of us view as a problem with the grounding scheme in this amplifier? Specifically, several of us have the neutral running to fuse and no chassis grounding or ground to earth. Do you believe these scheme is safe and acceptable?
This unit is supposed to have a 5 year warranty and many of us are just trying to figure out where things stand.
I'm not trying to come at anybody. I like the amp. I'm just trying to navigate through this and Frank Malitz and Bob just say: (a) the amp is awesome; (b) the amp is totally safe: (c) everyone who hears it loves it; (d) Amir and associates test it incorrectly.
I'm sure you can appreciate that when a consumer spends $3k on something they want to know they bought what was sold to them and it is safe.
Thank you for your time and any information you can provide. I can assure you that many consumers these days appreciate substantively meaningful responses form the manufacturers/dealers of the equipment they buy at this price level. Thank you!
Hello, Bob here. Here are my replies to your questions.
1. Is mounting the DC restorer circuit by gluing it vertically to the chassis part of the design?
Yes, the vertically mounted board is the power supply. The DC Restorer is on the main board, mechanically appropriate and sound. Bonding to the chassis was chosen. Bonding of assemblies, with service life greater than 20 years are common today, even in high end automobiles and aircraft. The low operating temps are compatible with bonding. Again, completely appropriate and sound.
2. Is mounting the meter to the chassis by gluing it part of the design?
Yes. We have used this meter many years without any failures. Serviceability is not likely to be of concern. Manufacturing Engineering chose to bond the meter.
3. Are the Edcor 15w OPTs part of the design?
Yes. They work quite well driving loudspeakers. In combination with back EMF feedback, and our DC restorer tracking bias supply, the ability of a tube amp to increase voltage with increases in impedance at low frequencies is inherent in my design. Together, these make music as a system.
4. What gauge hookup wire is supposed to be running from the PCB to the speaker output terminals?
22 gauge was determined to be proper by Manufacturing Engineers. A change to larger diameter (14 gauge) came later in the first year of production for cosmetic reasons. Units over the last 2 years have heavier wiring.
5. Does the design-manufacturing process allow for substitution of Panasonic film caps with Suntan brand or other lesser known caps?
Yes. Supply chain issues have limited choices of brand names at times. Parts that meet or exceed the original part specs are acceptable.
6. Have there been reports of transformer hum? I have owned two units and both hum/buzz at the transformers with no signal and volume totally attenuated (not a sound coming from the speakers, but buzz/hum coming from the transformers)
You have some power transformer hum. All three transformers mount directly to the chassis. Transformer hum can become microphonic in tube amps and make the situation worse. Most of the amps are quiet, but a few have hummed. The later units had isolation added and the issue was resolved. You can return your amp for the update at no charge. We will pay the shipping both directions.
7. Frank Malitz stated there was a problem with transformers when the vendor deviated from specification, and that resolved. Would that vendor be Edcor? What can be done to silence the transformers for those with those issues?
The Edcor products are high quality and were never an issue. Although the chassis is 1/8” thick aluminum, a slight sympathetic resonance can amplify the hum to audible levels. Talk to your dealer or call the phone number on my web site. We will make the improvements at no charge.
8. Grounding. Are you aware of what many of us view as a problem with the grounding scheme in this amplifier? Specifically, several of us have the neutral running to fuse and no chassis grounding or ground to earth. Do you believe that this scheme is safe and acceptable?
Yes, it is safe. Note most audio product use ungrounded cords. We have done this for several decades and over untold thousands of products with nary an issue.
If a high voltage wire were to touch the inside of the chassis the B+ fuse will blow.
If by chance, the power cord was wired incorrectly by a builder, it would likely cause hum. Please return the unit. We will pay shipping both directions and check it. If you prefer to have the earth ground connected, we can also do that at no charge.
This unit is supposed to have a 5 year warranty and many of us are just trying to figure out where things stand.
It does have a 5 year warranty. From the original date of purchase with a receipt.
The amplifier sounds wonderful with adequate reserves while driving loudspeaker loads.
I have been designing amplifiers since college, and since 1972 as a business. The 275 sounds and performs exactly the way I intended. I have designed and built many conventional amplifiers that test terrific by conventional standards. I have been doing this most of life. The specifications are being updated to better quantify our test procedures.
We are tooling up presently for manufacture under my close guidance and oversight.
Thank you for bringing this to my attention. I have some good people on my team. I have some new ideas coming in 2022 and some long term plans for my business which I think everyone will find exciting. Feel free to contact us from our website or call the phone number listed (815) 985-3557.
Warmest and best,
Bob Carver
bowlus.com
